Ccnt1

UniProt ID: Q9QWV9
Organism: Mus musculus
Review Status: COMPLETE
📝 Provide Detailed Feedback

Gene Description

Cyclin T1 is the cyclin regulatory subunit of P-TEFb, partnering with CDK9 to promote RNA polymerase II pause release and productive transcription elongation. It binds 7SK snRNA in the inactive 7SK snRNP/P-TEFb regulatory pool and is recruited to chromatin and transcription factors during gene activation. The histidine-rich region can support transcription-associated condensate/scaffold behavior, but the conserved core role is activation and targeting of CDK9-dependent transcription elongation rather than general DNA binding or cell division.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0005634 nucleus
IBA
GO_REF:0000033
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0032786 positive regulation of DNA-templated transcription, elongation
IBA
GO_REF:0000033
MODIFY
Summary: The existing term is too broad or incorrectly framed for Cyclin T1.
Reason: Cyclin T1 acts by activating/targeting CDK9 in P-TEFb for RNA polymerase II pause release, so the proposed replacement captures the mechanism more precisely.
Supporting Evidence:
file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
Cyclin T1 functions as the CDK9 cyclin partner in P-TEFb, enabling RNAPII transcriptional elongation by supporting phosphorylation events required for RNAPII pause release and productive elongation.
GO:0045944 positive regulation of transcription by RNA polymerase II
IBA
GO_REF:0000033
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0061575 cyclin-dependent protein serine/threonine kinase activator activity
IBA
GO_REF:0000033
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
Supporting Evidence:
file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
The core P-TEFb heterodimer is CDK9-Cyclin T1. CDK9 is the catalytic kinase; Cyclin T1 is the cyclin subunit that enables CDK9 activity within transcriptional complexes.
GO:0008024 cyclin/CDK positive transcription elongation factor complex
IBA
GO_REF:0000033
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0005634 nucleus
IEA
GO_REF:0000120
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0006357 regulation of transcription by RNA polymerase II
IEA
GO_REF:0000002
MODIFY
Summary: The existing term is too broad or incorrectly framed for Cyclin T1.
Reason: Cyclin T1 acts by activating/targeting CDK9 in P-TEFb for RNA polymerase II pause release, so the proposed replacement captures the mechanism more precisely.
GO:0016538 cyclin-dependent protein serine/threonine kinase regulator activity
IEA
GO_REF:0000002
MODIFY
Summary: The existing term is too broad or incorrectly framed for Cyclin T1.
Reason: Cyclin T1 acts by activating/targeting CDK9 in P-TEFb for RNA polymerase II pause release, so the proposed replacement captures the mechanism more precisely.
GO:0051301 cell division
IEA
GO_REF:0000043
MARK AS OVER ANNOTATED
Summary: The annotation overstates direct DNA/cell-cycle function or uses vague binding.
Reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a general DNA-binding protein or independent cell-division factor.
GO:0005515 protein binding
IPI
PMID:20434984
c-Myc regulates transcriptional pause release.
MARK AS OVER ANNOTATED
Summary: The annotation overstates direct DNA/cell-cycle function or uses vague binding.
Reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a general DNA-binding protein or independent cell-division factor.
Supporting Evidence:
PMID:20434984
c-Myc regulates transcriptional pause release.
GO:0005515 protein binding
IPI
PMID:22922464
Bromodomain-dependent stage-specific male genome programming...
MARK AS OVER ANNOTATED
Summary: The annotation overstates direct DNA/cell-cycle function or uses vague binding.
Reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a general DNA-binding protein or independent cell-division factor.
Supporting Evidence:
PMID:22922464
Bromodomain-dependent stage-specific male genome programming by Brdt.
GO:0005634 nucleus
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0005654 nucleoplasm
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0008024 cyclin/CDK positive transcription elongation factor complex
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0032968 positive regulation of transcription elongation by RNA polymerase II
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
Supporting Evidence:
file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
Cyclin T1 functions as the CDK9 cyclin partner in P-TEFb, enabling RNAPII transcriptional elongation by supporting phosphorylation events required for RNAPII pause release and productive elongation.
GO:0043923 host-mediated activation of viral transcription
ISO
GO_REF:0000119
KEEP AS NON CORE
Summary: Supported context-specific localization or viral co-option.
Reason: The annotation is biologically plausible but peripheral to the conserved P-TEFb transcription elongation function.
GO:0045944 positive regulation of transcription by RNA polymerase II
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0061575 cyclin-dependent protein serine/threonine kinase activator activity
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0070063 RNA polymerase binding
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0070691 P-TEFb complex
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
Supporting Evidence:
file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
Mouse Ccnt1 encodes Cyclin T1, a nuclear cyclin-family regulatory subunit that forms P-TEFb with CDK9.
GO:0097322 7SK snRNA binding
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0140297 DNA-binding transcription factor binding
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0140693 molecular condensate scaffold activity
ISO
GO_REF:0000119
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0003677 DNA binding
IEA
GO_REF:0000107
MARK AS OVER ANNOTATED
Summary: The annotation overstates direct DNA/cell-cycle function or uses vague binding.
Reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a general DNA-binding protein or independent cell-division factor.
GO:0005654 nucleoplasm
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0008024 cyclin/CDK positive transcription elongation factor complex
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0032968 positive regulation of transcription elongation by RNA polymerase II
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0043923 host-mediated activation of viral transcription
IEA
GO_REF:0000107
KEEP AS NON CORE
Summary: Supported context-specific localization or viral co-option.
Reason: The annotation is biologically plausible but peripheral to the conserved P-TEFb transcription elongation function.
GO:0045944 positive regulation of transcription by RNA polymerase II
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0061575 cyclin-dependent protein serine/threonine kinase activator activity
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0070063 RNA polymerase binding
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0070691 P-TEFb complex
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0097322 7SK snRNA binding
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0140297 DNA-binding transcription factor binding
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0140693 molecular condensate scaffold activity
IEA
GO_REF:0000107
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0005829 cytosol
ISO
GO_REF:0000119
KEEP AS NON CORE
Summary: Supported context-specific localization or viral co-option.
Reason: The annotation is biologically plausible but peripheral to the conserved P-TEFb transcription elongation function.
GO:0032968 positive regulation of transcription elongation by RNA polymerase II
ISS
GO_REF:0000024
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0070691 P-TEFb complex
ISS
GO_REF:0000024
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0061575 cyclin-dependent protein serine/threonine kinase activator activity
ISS
GO_REF:0000024
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0140693 molecular condensate scaffold activity
ISS
GO_REF:0000024
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0019901 protein kinase binding
IDA
PMID:22547058
Cyclin K-containing kinase complexes maintain self-renewal i...
REMOVE
Summary: The cited paper does not support Ccnt1/CDK9 protein kinase binding.
Reason: PMID:22547058 concerns cyclin K-containing CDK12/CDK13 complexes in mouse embryonic stem cells and states that cyclin K did not interact with CDK9 in cells. It should not be used to support a Ccnt1 protein kinase binding annotation.
Supporting Evidence:
PMID:22547058
Cyclin K-containing kinase complexes maintain self-renewal in murine embryonic stem cells.
GO:0097322 7SK snRNA binding
ISS
GO_REF:0000024
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0008024 cyclin/CDK positive transcription elongation factor complex
ISS
GO_REF:0000024
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
GO:0003682 chromatin binding
IDA
PMID:18662700
The positive transcription elongation factor b is an essenti...
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
Supporting Evidence:
PMID:18662700
The positive transcription elongation factor b is an essential cofactor for the activation of transcription by myocyte enhancer factor 2.
GO:0000976 transcription cis-regulatory region binding
IDA
PMID:20570862
Multiple functions of Ldb1 required for beta-globin activati...
MARK AS OVER ANNOTATED
Summary: The annotation overstates direct DNA/cell-cycle function or uses vague binding.
Reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a general DNA-binding protein or independent cell-division factor.
Supporting Evidence:
PMID:20570862
Multiple functions of Ldb1 required for beta-globin activation during erythroid differentiation.
GO:0008024 cyclin/CDK positive transcription elongation factor complex
TAS
PMID:20570862
Multiple functions of Ldb1 required for beta-globin activati...
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
Supporting Evidence:
PMID:20570862
Multiple functions of Ldb1 required for beta-globin activation during erythroid differentiation.
GO:0003677 DNA binding
ISO
PMID:16109376
The bromodomain protein Brd4 is a positive regulatory compon...
MARK AS OVER ANNOTATED
Summary: The annotation overstates direct DNA/cell-cycle function or uses vague binding.
Reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a general DNA-binding protein or independent cell-division factor.
Supporting Evidence:
PMID:16109376
The bromodomain protein Brd4 is a positive regulatory component of P-TEFb and stimulates RNA polymerase II-dependent transcription.
GO:0005634 nucleus
IDA
PMID:16109376
The bromodomain protein Brd4 is a positive regulatory compon...
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
Supporting Evidence:
PMID:16109376
The bromodomain protein Brd4 is a positive regulatory component of P-TEFb and stimulates RNA polymerase II-dependent transcription.
GO:0006468 protein phosphorylation
ISO
PMID:16109376
The bromodomain protein Brd4 is a positive regulatory compon...
MODIFY
Summary: The existing term is too broad or incorrectly framed for Cyclin T1.
Reason: Cyclin T1 acts by activating/targeting CDK9 in P-TEFb for RNA polymerase II pause release, so the proposed replacement captures the mechanism more precisely.
Supporting Evidence:
PMID:16109376
The bromodomain protein Brd4 is a positive regulatory component of P-TEFb and stimulates RNA polymerase II-dependent transcription.
GO:0017069 snRNA binding
IDA
PMID:16109376
The bromodomain protein Brd4 is a positive regulatory compon...
ACCEPT
Summary: Supported P-TEFb regulatory function.
Reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
Supporting Evidence:
PMID:16109376
The bromodomain protein Brd4 is a positive regulatory component of P-TEFb and stimulates RNA polymerase II-dependent transcription.
file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
A substantial fraction of P-TEFb is sequestered in an inactive ribonucleoprotein complex organized around 7SK snRNA, with protein components including HEXIM1/2, LARP7, and MePCE.

Core Functions

Cyclin T1 activates and recruits CDK9 as part of P-TEFb to stimulate RNA polymerase II transcription elongation.

Supporting Evidence:
  • file:mouse/Ccnt1/Ccnt1-uniprot.txt
    Regulatory subunit of the cyclin-dependent kinase pair
  • file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
    Cyclin T1 functions as the CDK9 cyclin partner in P-TEFb, enabling RNAPII transcriptional elongation by supporting phosphorylation events required for RNAPII pause release and productive elongation.
  • file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
    Mouse Ccnt1 encodes Cyclin T1, a nuclear cyclin-family regulatory subunit that forms P-TEFb with CDK9.

References

Gene Ontology annotation through association of InterPro records with GO terms
Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara
Automated transfer of experimentally-verified manual GO annotation data to mouse-human orthologs
Combined Automated Annotation using Multiple IEA Methods
The bromodomain protein Brd4 is a positive regulatory component of P-TEFb and stimulates RNA polymerase II-dependent transcription.
The positive transcription elongation factor b is an essential cofactor for the activation of transcription by myocyte enhancer factor 2.
c-Myc regulates transcriptional pause release.
Multiple functions of Ldb1 required for beta-globin activation during erythroid differentiation.
Cyclin K-containing kinase complexes maintain self-renewal in murine embryonic stem cells.
Bromodomain-dependent stage-specific male genome programming by Brdt.
file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
Falcon deep research synthesis for mouse Ccnt1
  • Cyclin T1 is the CDK9 regulatory cyclin in P-TEFb that promotes RNA polymerase II pause release and productive transcription elongation.
    "Cyclin T1 functions as the CDK9 cyclin partner in P-TEFb, enabling RNAPII transcriptional elongation by supporting phosphorylation events required for RNAPII pause release and productive elongation."

📚 Additional Documentation

Deep Research Falcon

(Ccnt1-deep-research-falcon.md)

provider: falcon
model: Edison Scientific Literature
cached: false
start_time: '2026-05-03T16:23:20.134940'
end_time: '2026-05-03T16:31:14.536314'
duration_seconds: 474.4
template_file: templates/gene_research_go_focused.md
template_variables:
organism: mouse
gene_id: Ccnt1
gene_symbol: Ccnt1
uniprot_accession: Q9QWV9
protein_description: 'RecName: Full=Cyclin-T1; Short=CycT1; Short=Cyclin-T;'
gene_info: Name=Ccnt1;
organism_full: Mus musculus (Mouse).
protein_family: Belongs to the cyclin family. Cyclin C subfamily.
protein_domains: Cyclin-like_dom. (IPR013763); Cyclin-like_sf. (IPR036915); Cyclin/Ssn8.
(IPR043198); CYCLIN_CCNT1_rpt2. (IPR047320); Cyclin_N. (IPR006671)
provider_config:
timeout: 600
max_retries: 3
parameters:
allowed_domains: []
temperature: 0.1
citation_count: 38


Question

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

  • UniProt Accession: Q9QWV9
  • Protein Description: RecName: Full=Cyclin-T1; Short=CycT1; Short=Cyclin-T;
  • Gene Information: Name=Ccnt1;
  • Organism (full): Mus musculus (Mouse).
  • Protein Family: Belongs to the cyclin family. Cyclin C subfamily.
  • Key Domains: Cyclin-like_dom. (IPR013763); Cyclin-like_sf. (IPR036915); Cyclin/Ssn8. (IPR043198); CYCLIN_CCNT1_rpt2. (IPR047320); Cyclin_N. (IPR006671)

MANDATORY VERIFICATION STEPS:

  1. Check if the gene symbol "Ccnt1" matches the protein description above
  2. Verify the organism is correct: Mus musculus (Mouse).
  3. Check if protein family/domains align with what you find in literature
  4. If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'Ccnt1' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information

Research Target:

Please provide a comprehensive research report on the gene Ccnt1 (gene ID: Ccnt1, UniProt: Q9QWV9) in mouse.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Output

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on:
1. Key concepts and definitions with current understanding
2. Recent developments and latest research (prioritize 2023-2024 sources)
3. Current applications and real-world implementations
4. Expert opinions and analysis from authoritative sources
5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available.
Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Gene Research for Functional Annotation

⚠️ CRITICAL: Gene/Protein Identification Context

BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.

Target Gene/Protein Identity (from UniProt):

  • UniProt Accession: Q9QWV9
  • Protein Description: RecName: Full=Cyclin-T1; Short=CycT1; Short=Cyclin-T;
  • Gene Information: Name=Ccnt1;
  • Organism (full): Mus musculus (Mouse).
  • Protein Family: Belongs to the cyclin family. Cyclin C subfamily.
  • Key Domains: Cyclin-like_dom. (IPR013763); Cyclin-like_sf. (IPR036915); Cyclin/Ssn8. (IPR043198); CYCLIN_CCNT1_rpt2. (IPR047320); Cyclin_N. (IPR006671)

MANDATORY VERIFICATION STEPS:

  1. Check if the gene symbol "Ccnt1" matches the protein description above
  2. Verify the organism is correct: Mus musculus (Mouse).
  3. Check if protein family/domains align with what you find in literature
  4. If you find literature for a DIFFERENT gene with the same or similar symbol, STOP

If Gene Symbol is Ambiguous or You Cannot Find Relevant Literature:

DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'Ccnt1' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information

Research Target:

Please provide a comprehensive research report on the gene Ccnt1 (gene ID: Ccnt1, UniProt: Q9QWV9) in mouse.

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Research report: Mouse Ccnt1 (Cyclin T1; UniProt Q9QWV9) — functional annotation

0) Target verification (mandatory)

The queried mouse gene Ccnt1 encodes Cyclin T1 (CycT1), the principal cyclin partner of CDK9 in the positive transcription elongation factor b (P-TEFb) complex, consistently matching the UniProt-provided description (Cyclin T1; cyclin family) and the mechanistic context across the retrieved literature (P-TEFb/7SK snRNP/SEC, RNAPII pause release). The main ambiguity risk is confusion with similarly named Cntn1 (Contactin-1), but those papers are unrelated to P-TEFb biology and were excluded from functional claims. (egloff2021cdk9keepsrna pages 1-2, bywater2020reactivationofmyc pages 1-2)

1) Key concepts and definitions (current understanding)

1.1 P-TEFb and RNAPII promoter-proximal pausing

A large fraction of mammalian protein-coding genes are regulated at promoter-proximal pausing, where RNAPII initiates but pauses ~tens of nucleotides downstream, with pausing enforced largely by DSIF and NELF. The transition to productive elongation requires P-TEFb, which phosphorylates RNAPII and pausing factors to enable elongation. (egloff2021cdk9keepsrna pages 1-2, zhou2022disruptingthecdk9cyclin pages 1-2, puidebat2025the7sksnrnp pages 1-3)

Definition (operational): In this context, Cyclin T1 (CCNT1/Ccnt1) is a regulatory cyclin subunit that binds CDK9 to form core P-TEFb and confers substrate recognition/complex behavior required for RNAPII pause release and productive transcription. (egloff2021cdk9keepsrna pages 1-2, zhou2022disruptingthecdk9cyclin pages 1-2)

1.2 Molecular role of Cyclin T1 within P-TEFb

Mechanistically, the core P-TEFb heterodimer is CDK9–Cyclin T1. CDK9 is the catalytic kinase; Cyclin T1 is the cyclin subunit that enables CDK9 activity within transcriptional complexes. When active on chromatin, P-TEFb phosphorylates RNAPII CTD Ser2, and phosphorylates DSIF/NELF to release RNAPII from pause sites and promote processive elongation. (zhou2022disruptingthecdk9cyclin pages 1-2, egloff2021cdk9keepsrna pages 1-2)

1.3 Domain/architecture concepts relevant to function

Cyclin T proteins are described as carrying an N-terminal cyclin box (cyclin fold) and a C-terminal histidine-rich region implicated in substrate recognition, consistent with Cyclin T proteins being cyclin-family regulators rather than enzymes catalyzing a small-molecule reaction. (egloff2021cdk9keepsrna pages 1-2)

2) Molecular function, complexes, and pathways

2.1 Core biochemical function (primary functional annotation)

Primary function: Mouse Cyclin T1 (Ccnt1 product) functions as the CDK9 cyclin partner in P-TEFb, enabling RNAPII transcriptional elongation by supporting phosphorylation events (RNAPII CTD Ser2; DSIF/NELF) required for RNAPII pause release and productive elongation. (zhou2022disruptingthecdk9cyclin pages 1-2, egloff2021cdk9keepsrna pages 1-2, puidebat2025the7sksnrnp pages 1-3)

This is not an enzyme with an independent catalytic reaction; its “substrate specificity” is mediated through its role in assembling and regulating the CDK9 kinase complex and recruitment to transcriptional targets. (egloff2021cdk9keepsrna pages 1-2, zhou2022disruptingthecdk9cyclin pages 1-2)

2.2 Major complexes that contain Cyclin T1

Inactive reservoir: 7SK snRNP (7SK/P-TEFb snRNP). A substantial fraction of P-TEFb is sequestered in an inactive ribonucleoprotein complex organized around 7SK snRNA, with protein components including HEXIM1/2, LARP7, and MePCE, which limits free/active CDK9–Cyclin T1 availability. (zhou2022disruptingthecdk9cyclin pages 1-2, puidebat2025the7sksnrnp pages 1-3, perezpepe20237skmethylationby pages 1-2)

Active recruitment complexes: Active P-TEFb is recruited to chromatin via BRD4–P-TEFb or via incorporation into the Super Elongation Complex (SEC), which is particularly important for stimulus-responsive transcription programs. (zhou2022disruptingthecdk9cyclin pages 1-2, puidebat2025the7sksnrnp pages 1-3, galbraith2019therapeutictargetingof pages 6-7)

Switching mechanism: Stress- or signal-induced 7SK disruption releases P-TEFb; one mechanistic study reports that released CDK9/Cyclin T1 can dissociate into monomers, and BRD4 or SEC can recruit these monomers to reassemble active P-TEFb on chromatin, including reactivation steps involving CDK9 T-loop autophosphorylation (T186). (zhou2022disruptingthecdk9cyclin pages 1-2)

2.3 Signaling-pathway coupling (example: EGF→METTL3→7SK m6A)

A 2023 study provides a concrete signaling-to-transcription mechanism: EGF signaling induces phosphorylation of METTL3, which methylates 7SK RNA (m6A). This methylation increases binding of HNRNP proteins and promotes release of HEXIM1/P-TEFb (CDK9/CCNT1), thereby enhancing transcriptional elongation. (perezpepe20237skmethylationby pages 1-2)

The associated figures include direct biochemical/omics evidence of 7SK m6A and a model connecting EGF/ERK, METTL3, 7SK methylation, and P-TEFb release. (perezpepe20237skmethylationby media 160b1369, perezpepe20237skmethylationby media b39d83df)

3) Cellular localization and where Cyclin T1 acts

Nuclear/transcriptional compartmentalization: CDK9 is described as a nuclear protein, and P-TEFb function is inherently nuclear and chromatin-associated when active. (egloff2021cdk9keepsrna pages 1-2, zhou2022disruptingthecdk9cyclin pages 1-2)

Chromatin-free vs chromatin-associated pools: Inactive 7SK-bound P-TEFb is described as largely chromatin-free, whereas BRD4- or SEC-associated P-TEFb is chromatin-associated. (zhou2022disruptingthecdk9cyclin pages 1-2)

Nuclear speckle association and isoform-dependent localization: Work discussing Cyclin T1 isoforms reports Cyclin T1 localization in nuclear speckle-rich regions and suggests truncated isoforms can display altered localization (including cytoplasmic presence) with functional consequences in viral transcription contexts. (alberio2024atruncatedisoform pages 13-14)

Mouse embryo nuclear foci: In mouse early embryos, maternal TDP-43 co-occupies with RNAPII as nuclear foci and biochemical evidence indicates TDP-43 binds Cyclin T1, supporting a role for Cyclin T1 in proper RNAPII configuration and zygotic genome activation (ZGA). (nie2023maternaltdp43interacts pages 1-2)

4) Mouse biology, phenotypes, and in vivo functional contexts

4.1 Heart: Cyclin T1 as a limiting determinant of P-TEFb output

Mouse cardiomyocyte studies emphasize that Cyclin T1 levels limit P-TEFb abundance and CDK9 stability, and that increased P-TEFb activity correlates with increased RNAPII phosphorylation and transcriptional output. Overexpression of Cyclin T1 in the mouse heart increases CDK9 and phosphorylated RNAPII; sustained elevation across development is associated with cardiac hypertrophy in transgenic contexts. (boikova2022hrasandmyc pages 1-2)

In a mouse model context, constitutive HRas activity increased Cyclin T1 expression; HRas plus Myc promoted cardiomyocyte cell-cycle progression but also cell death, whereas Myc plus Cyclin T1 supported extensive cardiomyocyte proliferation (supporting the idea that Cyclin T1/P-TEFb availability gates Myc-driven transcriptional programs in heart). (boikova2022hrasandmyc pages 1-2, bywater2020reactivationofmyc pages 1-2)

4.2 Early development: ZGA and transcriptional elongation control

Maternal TDP-43 deletion caused mouse embryos to arrest at the two-cell stage; TDP-43 binds Polr2a and Cyclin T1, and depletion reduced Pol II chromatin binding at major ZGA genes, implicating Cyclin T1/P-TEFb-related elongation control as part of the mechanism enabling major ZGA. (nie2023maternaltdp43interacts pages 1-2)

5) Mouse-specific sequence feature (important for species differences)

A widely used functional marker of rodent Cyclin T1 is the residue corresponding to human Cys261, which is critical for Tat-dependent HIV transcriptional activation. Mouse Cyclin T1 carries a Tyr at this position (mouse-like “C261Y” relative to human), reducing Tat/TAR-dependent transactivation and contributing to rodent non-permissivity for HIV-1 transcription. (behrens2023exploitingarodent pages 12-14, alberio2024atruncatedisoform pages 13-14)

A 2023 gene-editing study recoded this region in human CD4+ T cells to encode CCNT1.C261Y, yielding viable isogenic clones with little effect on host proliferation/basal CCNT1 but near-total inactivation of viral gene expression across multiple HIV-1 strains and related primate lentiviruses—demonstrating that this single mouse-informed change can be sufficient to block Tat-dependent transcriptional amplification. (behrens2023exploitingarodent pages 12-14)

6) Recent developments (prioritizing 2023–2024)

6.1 2023 — Signal-responsive 7SK modification couples growth-factor signaling to P-TEFb

Perez-Pepe et al. (Science Advances; 10 May 2023; https://doi.org/10.1126/sciadv.ade7500) established a mechanism in which METTL3-mediated m6A methylation of 7SK promotes release of HEXIM1/P-TEFb, enabling enhanced elongation in response to EGF signaling. This provides a modern model of how extracellular cues can “unlock” CDK9/CCNT1 activity. (perezpepe20237skmethylationby pages 1-2, perezpepe20237skmethylationby media b39d83df)

6.2 2023 — Mouse early embryo: Cyclin T1 in ZGA regulatory machinery

Nie et al. (Nature Communications; accepted 30 June 2023; https://doi.org/10.1038/s41467-023-39924-1) provides in vivo mouse evidence linking Cyclin T1 binding partners (maternal TDP-43) to RNAPII nuclear organization and major ZGA gene activation. (nie2023maternaltdp43interacts pages 1-2)

6.3 2023 — Functional separation in T cells: CCNT1 non-essential for many host transcripts but essential for HIV latency reactivation

Hafer et al. (Viruses; Aug 2023; https://doi.org/10.3390/v15091863) reported CCNT1 as the top hit in a CRISPR screen for HIV latency reactivation. In primary CD4+ T cell latency models, CCNT1 knockout prevented latency reactivation without impairing T cell activation, and RNA-seq suggested CCNT1 had minimal detectable impact on host transcripts after activation while strongly affecting proviral transcription. (hafer2023acrisprscreen pages 1-2)

6.4 2024 — Releasing P-TEFb from SEC as a latency reversal approach

Cisneros et al. (PLOS Pathogens; published 11 Sep 2024; https://doi.org/10.1371/journal.ppat.1012083) tested a small molecule inhibitor (KL-2) of P-TEFb/SEC interaction; KL-2 increased viral transcription and synergized with other latency reversing agents in cell models and enhanced reactivation in PBMCs from people living with HIV on suppressive ART, supporting SEC-bound P-TEFb as a therapeutically relevant reservoir of CDK9/CCNT1. (cisneros2024releaseofptefb pages 1-2)

7) Current applications and real-world implementations

7.1 Regenerative biology (mouse heart)

Mouse work suggests that elevating P-TEFb (CDK9–Cyclin T1) can re-engage Myc-driven transcription and proliferative potential in cardiomyocytes, positioning P-TEFb/Ccnt1 modulation as a candidate strategy for cardiac regeneration research. (bywater2020reactivationofmyc pages 1-2, boikova2022hrasandmyc pages 1-2)

7.2 HIV cure and antiviral strategies (leveraging rodent CCNT1 biology)

Several 2023–2024 studies use CCNT1 biology in applied directions:
- Gene editing (C261Y “mousification”) as a host-directed strategy to create Tat-resistant human T cells. (behrens2023exploitingarodent pages 12-14)
- Latency reversal approaches that manipulate P-TEFb pools (SEC release; PAF1C disruption discussed as a pausing regulator that interfaces with P-TEFb recruitment). (cisneros2024releaseofptefb pages 1-2, soliman2023enhancinghiv1latency pages 1-2)

These are not mouse therapies per se, but directly exploit the conserved CCNT1/P-TEFb mechanism and a mouse-specific residue difference to inform intervention design. (behrens2023exploitingarodent pages 12-14)

8) Expert opinions and authoritative synthesis

A detailed review of CDK9/P-TEFb emphasizes that CDK9 (with Cyclin T partners) is essential for productive transcription of most RNAPII genes via promoter-proximal pause release and that P-TEFb impacts initiation/termination and broader gene-expression coordination; this framing supports Cyclin T1 as a core transcriptional control node rather than a cell-cycle cyclin. (egloff2021cdk9keepsrna pages 1-2)

A mechanistic synthesis of 7SK snRNP regulation frames 7SK-bound P-TEFb as a dynamic “buffer” controlling CDK9 availability and highlights recruitment of active P-TEFb via BRD4 and SEC, and links dysregulation of this axis to disease states. (puidebat2025the7sksnrnp pages 1-3)

9) Quantitative statistics and data points from recent studies

Note: Many mechanistic P-TEFb studies report qualitative switching mechanisms; a limited number of retrieved texts provide directly stated quantitative effects.

  • In mouse females with oocyte-specific TDP-43 knockout, control females produced 8.8 ± 2.1 pups/litter, whereas TDP-43 oocyte knockout females produced no pups after extended mating, supporting essentiality of the pathway in early development (with Cyclin T1 as a binding partner in the mechanism). (nie2023maternaltdp43interacts pages 1-2)
  • In a comprehensive HIV latency reactivation CRISPR screen, CCNT1 was the top hit and had the largest effect on latency reversal across multiple LRAs; in primary CD4+ T cells, CCNT1 knockout blocked latency reactivation without affecting T cell activation. (hafer2023acrisprscreen pages 1-2)

10) Evidence map table (for rapid functional annotation)

Aspect Evidence summary Key sources with citation IDs URLs Publication dates
Identity/domains Mouse Ccnt1 encodes Cyclin T1 (CycT1), the major cyclin partner of CDK9 within P-TEFb. Reviews describe Cyclin T1/T2 proteins as carrying an N-terminal cyclin box and a C-terminal histidine-rich region implicated in substrate recognition; this matches the UniProt assignment to the cyclin family and cyclin-like domains (egloff2021cdk9keepsrna pages 1-2, shiozaki2018thecdk9–cyclint1 pages 15-17). Egloff 2021 (egloff2021cdk9keepsrna pages 1-2); Shiozaki et al. 2018 (shiozaki2018thecdk9–cyclint1 pages 15-17) https://doi.org/10.1007/s00018-021-03878-8 ; https://doi.org/10.1074/jbc.ra118.004706 2021-06-19; 2018-11
Molecular function Cyclin T1 is the regulatory cyclin subunit of P-TEFb (CDK9–Cyclin T1), which promotes RNA polymerase II pause release and productive elongation. In this complex, CDK9 phosphorylates RNAPII CTD Ser2 as well as DSIF and NELF; Cyclin T1 is also the preferred cyclin for HIV Tat-dependent recruitment of P-TEFb to TAR RNA (zhou2022disruptingthecdk9cyclin pages 1-2, egloff2021cdk9keepsrna pages 1-2, hafer2023acrisprscreen pages 1-2). Zhou et al. 2022 (zhou2022disruptingthecdk9cyclin pages 1-2); Egloff 2021 (egloff2021cdk9keepsrna pages 1-2); Hafer et al. 2023 (hafer2023acrisprscreen pages 1-2) https://doi.org/10.1093/nar/gkab1228 ; https://doi.org/10.1007/s00018-021-03878-8 ; https://doi.org/10.3390/v15091863 2022-12; 2021-06-19; 2023-08
Key complexes Ccnt1/Cyclin T1 functions in several transcriptional assemblies: core P-TEFb with CDK9, the inactive 7SK snRNP with 7SK RNA/HEXIM/LARP7/MePCE, and active chromatin-associated complexes with BRD4 or the Super Elongation Complex (SEC). Recent mechanistic work showed that stress can dissociate released CDK9/Cyclin T1 into monomers before BRD4 or SEC reassembles active P-TEFb on chromatin (zhou2022disruptingthecdk9cyclin pages 1-2, puidebat2025the7sksnrnp pages 1-3, galbraith2019therapeutictargetingof pages 6-7). Zhou et al. 2022 (zhou2022disruptingthecdk9cyclin pages 1-2); Puidebat & Egloff 2025 (puidebat2025the7sksnrnp pages 1-3); Galbraith et al. 2019 (galbraith2019therapeutictargetingof pages 6-7) https://doi.org/10.1093/nar/gkab1228 ; https://doi.org/10.1016/j.biochi.2025.05.003 ; https://doi.org/10.1080/21541264.2018.1539615 2022-12; 2025-05; 2019-11
Regulation Cyclin T1 abundance is a major determinant of P-TEFb levels and CDK9 protein stability in mouse heart. Regulation occurs through sequestration in 7SK snRNP, growth-factor signaling to 7SK methylation, reversible phosphorylation/dephosphorylation affecting Cyclin T1 stability, and developmental or oncogenic inputs such as HRas and Myc that raise Cyclin T1/P-TEFb activity (boikova2022hrasandmyc pages 1-2, perezpepe20237skmethylationby pages 1-2, ksionsko2024mechanisticcharacterizationof pages 17-21, bywater2020reactivationofmyc pages 1-2). Boikova et al. 2022 (boikova2022hrasandmyc pages 1-2); Perez-Pepe et al. 2023 (perezpepe20237skmethylationby pages 1-2); Ksionsko 2024 (ksionsko2024mechanisticcharacterizationof pages 17-21); Bywater et al. 2020 (bywater2020reactivationofmyc pages 1-2) https://doi.org/10.3389/fcvm.2022.948281 ; https://doi.org/10.1126/sciadv.ade7500 ; https://doi.org/10.53846/goediss-10686 ; https://doi.org/10.1038/s41467-020-15552-x 2022-10; 2023-05-10; 2024; 2020-04
Localization Functional evidence places Cyclin T1 primarily in the nucleus, associated with RNAPII transcription sites, chromatin-bound active elongation complexes, and nuclear speckle-rich regions; inactive 7SK-bound P-TEFb is described as largely chromatin-free. In mouse embryos, Cyclin T1 colocalizes with Pol II-related nuclear structures during zygotic genome activation (zhou2022disruptingthecdk9cyclin pages 1-2, alberio2024atruncatedisoform pages 13-14, nie2023maternaltdp43interacts pages 1-2). Zhou et al. 2022 (zhou2022disruptingthecdk9cyclin pages 1-2); Alberio et al. 2024 (alberio2024atruncatedisoform pages 13-14); Nie et al. 2023 (nie2023maternaltdp43interacts pages 1-2) https://doi.org/10.1093/nar/gkab1228 ; https://doi.org/10.3390/v16081176 ; https://doi.org/10.1038/s41467-023-39924-1 2022-12; 2024-07; 2023-07
Pathways/biological processes The main annotated role of Ccnt1 is transcriptional elongation control downstream of promoter-proximal pausing. In mouse and mammalian systems it contributes to Myc-driven transcriptional activation in cardiomyocytes, stress-responsive transcription through 7SK/P-TEFb switching, early embryonic zygotic genome activation, and specialized programs such as ATF4/CHOP signaling in vascular calcification (bywater2020reactivationofmyc pages 1-2, nie2023maternaltdp43interacts pages 1-2, shiozaki2018thecdk9–cyclint1 pages 15-17, perezpepe20237skmethylationby pages 1-2). Bywater et al. 2020 (bywater2020reactivationofmyc pages 1-2); Nie et al. 2023 (nie2023maternaltdp43interacts pages 1-2); Shiozaki et al. 2018 (shiozaki2018thecdk9–cyclint1 pages 15-17); Perez-Pepe et al. 2023 (perezpepe20237skmethylationby pages 1-2) https://doi.org/10.1038/s41467-020-15552-x ; https://doi.org/10.1038/s41467-023-39924-1 ; https://doi.org/10.1074/jbc.ra118.004706 ; https://doi.org/10.1126/sciadv.ade7500 2020-04; 2023-07; 2018-11; 2023-05-10
Mouse-specific features A well-known species-specific difference is the mouse-like Tyr at residue 261 of Cyclin T1, corresponding to human Cys261; this weakens Tat/TAR-dependent transactivation and helps explain rodent resistance to HIV-1 transcription. Engineering the mouse-like C261Y change into human CCNT1 strongly impaired Tat-driven viral expression without major effects on host-cell proliferation or basal CCNT1 expression (behrens2023exploitingarodent pages 12-14, alberio2024atruncatedisoform pages 13-14). Behrens et al. 2023 (behrens2023exploitingarodent pages 12-14); Alberio et al. 2024 (alberio2024atruncatedisoform pages 13-14) https://doi.org/10.1128/mbio.00420-23 ; https://doi.org/10.3390/v16081176 2023-10; 2024-07
Recent developments 2023-2024 Recent studies refined Ccnt1 biology by showing: EGF–ERK–METTL3 signaling methylates 7SK and releases CCNT1/CDK9 for elongation; maternal TDP-43 binds Cyclin T1 and supports mouse major ZGA; SEC-disrupting small molecules can release P-TEFb to enhance HIV latency reversal; and CRISPR studies found CCNT1 is dispensable for many host T-cell transcripts yet crucial for HIV reactivation (perezpepe20237skmethylationby pages 1-2, nie2023maternaltdp43interacts pages 1-2, cisneros2024releaseofptefb pages 1-2, hafer2023acrisprscreen pages 1-2). Perez-Pepe et al. 2023 (perezpepe20237skmethylationby pages 1-2); Nie et al. 2023 (nie2023maternaltdp43interacts pages 1-2); Cisneros et al. 2024 (cisneros2024releaseofptefb pages 1-2); Hafer et al. 2023 (hafer2023acrisprscreen pages 1-2) https://doi.org/10.1126/sciadv.ade7500 ; https://doi.org/10.1038/s41467-023-39924-1 ; https://doi.org/10.1371/journal.ppat.1012083 ; https://doi.org/10.3390/v15091863 2023-05-10; 2023-07; 2024-09-11; 2023-08
Applications Real-world applications center on transcription-targeted therapeutics and regenerative biology. Manipulating Cyclin T1/P-TEFb has been proposed for cardiac regeneration in mouse heart, while in infection biology CCNT1 is a target for HIV cure strategies including gene editing, latency reversal combinations, and Tat-directed antiviral approaches (bywater2020reactivationofmyc pages 1-2, behrens2023exploitingarodent pages 12-14, cisneros2024releaseofptefb pages 1-2, soliman2023enhancinghiv1latency pages 1-2). Bywater et al. 2020 (bywater2020reactivationofmyc pages 1-2); Behrens et al. 2023 (behrens2023exploitingarodent pages 12-14); Cisneros et al. 2024 (cisneros2024releaseofptefb pages 1-2); Soliman et al. 2023 (soliman2023enhancinghiv1latency pages 1-2) https://doi.org/10.1038/s41467-020-15552-x ; https://doi.org/10.1128/mbio.00420-23 ; https://doi.org/10.1371/journal.ppat.1012083 ; https://doi.org/10.1126/sciadv.adf2468 2020-04; 2023-10; 2024-09-11; 2023-03-08

Table: This table summarizes the functional annotation of mouse Ccnt1/Cyclin T1 across identity, mechanism, complexes, regulation, localization, pathways, species-specific features, recent studies, and applications. It is designed as a compact evidence map with direct citation IDs, URLs, and dates for rapid use in the final report.

11) Summary functional annotation (mouse Ccnt1 / Cyclin T1)

Mouse Ccnt1 encodes Cyclin T1, a nuclear cyclin-family regulatory subunit that forms P-TEFb with CDK9. Its primary role is to enable RNAPII pause release and productive transcription elongation through P-TEFb’s kinase activity on RNAPII CTD Ser2 and associated pausing factors, with its availability controlled by dynamic sequestration in 7SK snRNP and recruitment by BRD4 and SEC to chromatin. In mouse biology, Cyclin T1 levels can gate transcriptional programs in differentiated cardiomyocytes and contribute to early embryonic transcriptional activation (ZGA). A key mouse-specific residue (Tyr at the position corresponding to human Cys261) is functionally important in species differences for HIV Tat transactivation and has been leveraged to engineer Tat-resistant human T cells. (boikova2022hrasandmyc pages 1-2, zhou2022disruptingthecdk9cyclin pages 1-2, perezpepe20237skmethylationby pages 1-2, nie2023maternaltdp43interacts pages 1-2, behrens2023exploitingarodent pages 12-14)

References

  1. (egloff2021cdk9keepsrna pages 1-2): Sylvain Egloff. Cdk9 keeps rna polymerase ii on track. Cellular and Molecular Life Sciences: CMLS, 78:5543-5567, Jun 2021. URL: https://doi.org/10.1007/s00018-021-03878-8, doi:10.1007/s00018-021-03878-8. This article has 106 citations.

  2. (bywater2020reactivationofmyc pages 1-2): Megan J. Bywater, Deborah L. Burkhart, Jasmin Straube, Arianna Sabò, Vera Pendino, James E. Hudson, Gregory A. Quaife-Ryan, Enzo R. Porrello, James Rae, Robert G. Parton, Theresia R. Kress, Bruno Amati, Trevor D. Littlewood, Gerard I. Evan, and Catherine H. Wilson. Reactivation of myc transcription in the mouse heart unlocks its proliferative capacity. Nature Communications, Apr 2020. URL: https://doi.org/10.1038/s41467-020-15552-x, doi:10.1038/s41467-020-15552-x. This article has 64 citations and is from a highest quality peer-reviewed journal.

  3. (zhou2022disruptingthecdk9cyclin pages 1-2): Kai Zhou, Songkuan Zhuang, Fulong Liu, Yanheng Chen, You Li, Shihui Wang, Yuxuan Li, Huixin Wen, Xiaohua Lin, Jie Wang, Yue Huang, Cailing He, Nan Xu, Zongshu Li, Lang Xu, Zixuan Zhang, Lin-Feng Chen, Ruichuan Chen, and Min Liu. Disrupting the cdk9/cyclin t1 heterodimer of 7sk snrnp for the brd4 and aff1/4 guided reconstitution of active p-tefb. Nucleic Acids Research, 50:750-762, Dec 2022. URL: https://doi.org/10.1093/nar/gkab1228, doi:10.1093/nar/gkab1228. This article has 19 citations and is from a highest quality peer-reviewed journal.

  4. (puidebat2025the7sksnrnp pages 1-3): Oriana Puidebat and Sylvain Egloff. The 7sk snrnp complex: a critical regulator in carcinogenesis. Biochimie, May 2025. URL: https://doi.org/10.1016/j.biochi.2025.05.003, doi:10.1016/j.biochi.2025.05.003. This article has 2 citations and is from a peer-reviewed journal.

  5. (perezpepe20237skmethylationby pages 1-2): Marcelo Perez-Pepe, Anthony W. Desotell, Hengyi Li, Wenxue Li, Bing Han, Qishan Lin, Daryl E. Klein, Yansheng Liu, Hani Goodarzi, and Claudio R. Alarcón. 7sk methylation by mettl3 promotes transcriptional activity. Science Advances, May 2023. URL: https://doi.org/10.1126/sciadv.ade7500, doi:10.1126/sciadv.ade7500. This article has 24 citations and is from a highest quality peer-reviewed journal.

  6. (galbraith2019therapeutictargetingof pages 6-7): Matthew D. Galbraith, Heather Bender, and Joaquín M. Espinosa. Therapeutic targeting of transcriptional cyclin-dependent kinases. Transcription, 10:118-136, Nov 2019. URL: https://doi.org/10.1080/21541264.2018.1539615, doi:10.1080/21541264.2018.1539615. This article has 107 citations and is from a peer-reviewed journal.

  7. (perezpepe20237skmethylationby media 160b1369): Marcelo Perez-Pepe, Anthony W. Desotell, Hengyi Li, Wenxue Li, Bing Han, Qishan Lin, Daryl E. Klein, Yansheng Liu, Hani Goodarzi, and Claudio R. Alarcón. 7sk methylation by mettl3 promotes transcriptional activity. Science Advances, May 2023. URL: https://doi.org/10.1126/sciadv.ade7500, doi:10.1126/sciadv.ade7500. This article has 24 citations and is from a highest quality peer-reviewed journal.

  8. (perezpepe20237skmethylationby media b39d83df): Marcelo Perez-Pepe, Anthony W. Desotell, Hengyi Li, Wenxue Li, Bing Han, Qishan Lin, Daryl E. Klein, Yansheng Liu, Hani Goodarzi, and Claudio R. Alarcón. 7sk methylation by mettl3 promotes transcriptional activity. Science Advances, May 2023. URL: https://doi.org/10.1126/sciadv.ade7500, doi:10.1126/sciadv.ade7500. This article has 24 citations and is from a highest quality peer-reviewed journal.

  9. (alberio2024atruncatedisoform pages 13-14): Tiziana Alberio, Mariam Shallak, Amruth Kaleem Basha Shaik, Roberto Sergio Accolla, and Greta Forlani. A truncated isoform of cyclin t1 could contribute to the non-permissive hiv-1 phenotype of u937 promonocytic cells. Viruses, 16:1176, Jul 2024. URL: https://doi.org/10.3390/v16081176, doi:10.3390/v16081176. This article has 0 citations.

  10. (nie2023maternaltdp43interacts pages 1-2): Xiaoqing Nie, Qianhua Xu, Chengpeng Xu, Fengling Chen, Qizhi Wang, Dandan Qin, Rui Wang, Zheng Gao, Xukun Lu, Xinai Yang, Yu Wu, Chen Gu, Wei Xie, and Lei Li. Maternal tdp-43 interacts with rna pol ii and regulates zygotic genome activation. Nature Communications, Jul 2023. URL: https://doi.org/10.1038/s41467-023-39924-1, doi:10.1038/s41467-023-39924-1. This article has 19 citations and is from a highest quality peer-reviewed journal.

  11. (boikova2022hrasandmyc pages 1-2): Aleksandra Boikova, Megan J. Bywater, Gregory A. Quaife-Ryan, Jasmin Straube, Lucy Thompson, Camilla Ascanelli, Trevor D. Littlewood, Gerard I. Evan, James E. Hudson, and Catherine H. Wilson. Hras and myc synergistically induce cell cycle progression and apoptosis of murine cardiomyocytes. Frontiers in Cardiovascular Medicine, Oct 2022. URL: https://doi.org/10.3389/fcvm.2022.948281, doi:10.3389/fcvm.2022.948281. This article has 4 citations and is from a peer-reviewed journal.

  12. (behrens2023exploitingarodent pages 12-14): Ryan T. Behrens, Jyothi Krishnaswamy Rajashekar, James W. Bruce, Edward L. Evans, Amelia M. Hansen, Natalia Salazar-Quiroz, Lacy M. Simons, Paul Ahlquist, Judd F. Hultquist, Priti Kumar, and Nathan M. Sherer. Exploiting a rodent cell block for intrinsic resistance to hiv-1 gene expression in human t cells. mBio, Oct 2023. URL: https://doi.org/10.1128/mbio.00420-23, doi:10.1128/mbio.00420-23. This article has 4 citations and is from a domain leading peer-reviewed journal.

  13. (hafer2023acrisprscreen pages 1-2): Terry L. Hafer, Abby Felton, Yennifer Delgado, Harini Srinivasan, and Michael Emerman. A crispr screen of hiv dependency factors reveals that ccnt1 is non-essential in t cells but required for hiv-1 reactivation from latency. Viruses, 15:1863, Aug 2023. URL: https://doi.org/10.3390/v15091863, doi:10.3390/v15091863. This article has 9 citations.

  14. (cisneros2024releaseofptefb pages 1-2): William J. Cisneros, S. Soliman, Miriam Walter, L. Simons, Daphne Cornish, Simone De Fabritiis, Ariel W. Halle, Eun-Young Kim, Steven M. Wolinsky, Ramon Lorenzo-Redondo, A. Shilatifard, and J. Hultquist. Release of p-tefb from the super elongation complex promotes hiv-1 latency reversal. PLOS Pathogens, Sep 2024. URL: https://doi.org/10.1371/journal.ppat.1012083, doi:10.1371/journal.ppat.1012083. This article has 5 citations and is from a highest quality peer-reviewed journal.

  15. (soliman2023enhancinghiv1latency pages 1-2): Shimaa H. A. Soliman, William J. Cisneros, Marta Iwanaszko, Yuki Aoi, Sheetal Ganesan, Miriam Walter, Jacob M. Zeidner, Rama K. Mishra, Eun-Young Kim, Steven M. Wolinsky, Judd F. Hultquist, and Ali Shilatifard. Enhancing hiv-1 latency reversal through regulating the elongating rna pol ii pause-release by a small-molecule disruptor of paf1c. Science Advances, Mar 2023. URL: https://doi.org/10.1126/sciadv.adf2468, doi:10.1126/sciadv.adf2468. This article has 25 citations and is from a highest quality peer-reviewed journal.

  16. (shiozaki2018thecdk9–cyclint1 pages 15-17): Yuji Shiozaki, Kayo Okamura, Shohei Kohno, Audrey L. Keenan, Kristina Williams, Xiaoyun Zhao, Wallace S. Chick, Shinobu Miyazaki-Anzai, and Makoto Miyazaki. The cdk9–cyclin t1 complex mediates saturated fatty acid–induced vascular calcification by inducing expression of the transcription factor chop. Journal of Biological Chemistry, 293:17008-17020, Nov 2018. URL: https://doi.org/10.1074/jbc.ra118.004706, doi:10.1074/jbc.ra118.004706. This article has 37 citations and is from a domain leading peer-reviewed journal.

  17. (ksionsko2024mechanisticcharacterizationof pages 17-21): Nora Anna Maria Ksionsko. Mechanistic characterization of cdk9 inhibition in t-cell lymphoma. ArXiv, 2024. URL: https://doi.org/10.53846/goediss-10686, doi:10.53846/goediss-10686. This article has 0 citations.

Citations

  1. alberio2024atruncatedisoform pages 13-14
  2. boikova2022hrasandmyc pages 1-2
  3. behrens2023exploitingarodent pages 12-14
  4. hafer2023acrisprscreen pages 1-2
  5. cisneros2024releaseofptefb pages 1-2
  6. galbraith2019therapeutictargetingof pages 6-7
  7. ksionsko2024mechanisticcharacterizationof pages 17-21
  8. bywater2020reactivationofmyc pages 1-2
  9. https://doi.org/10.1126/sciadv.ade7500
  10. https://doi.org/10.1038/s41467-023-39924-1
  11. https://doi.org/10.3390/v15091863
  12. https://doi.org/10.1371/journal.ppat.1012083
  13. https://doi.org/10.1007/s00018-021-03878-8
  14. https://doi.org/10.1074/jbc.ra118.004706
  15. https://doi.org/10.1093/nar/gkab1228
  16. https://doi.org/10.1016/j.biochi.2025.05.003
  17. https://doi.org/10.1080/21541264.2018.1539615
  18. https://doi.org/10.3389/fcvm.2022.948281
  19. https://doi.org/10.53846/goediss-10686
  20. https://doi.org/10.1038/s41467-020-15552-x
  21. https://doi.org/10.3390/v16081176
  22. https://doi.org/10.1128/mbio.00420-23
  23. https://doi.org/10.1126/sciadv.adf2468
  24. https://doi.org/10.1007/s00018-021-03878-8,
  25. https://doi.org/10.1038/s41467-020-15552-x,
  26. https://doi.org/10.1093/nar/gkab1228,
  27. https://doi.org/10.1016/j.biochi.2025.05.003,
  28. https://doi.org/10.1126/sciadv.ade7500,
  29. https://doi.org/10.1080/21541264.2018.1539615,
  30. https://doi.org/10.3390/v16081176,
  31. https://doi.org/10.1038/s41467-023-39924-1,
  32. https://doi.org/10.3389/fcvm.2022.948281,
  33. https://doi.org/10.1128/mbio.00420-23,
  34. https://doi.org/10.3390/v15091863,
  35. https://doi.org/10.1371/journal.ppat.1012083,
  36. https://doi.org/10.1126/sciadv.adf2468,
  37. https://doi.org/10.1074/jbc.ra118.004706,
  38. https://doi.org/10.53846/goediss-10686,

📄 View Raw YAML

id: Q9QWV9
gene_symbol: Ccnt1
product_type: PROTEIN
status: COMPLETE
description: 'Cyclin T1 is the cyclin regulatory subunit of P-TEFb, partnering with CDK9 to
  promote RNA polymerase II pause release and productive transcription elongation. It binds
  7SK snRNA in the inactive 7SK snRNP/P-TEFb regulatory pool and is recruited to chromatin
  and transcription factors during gene activation. The histidine-rich region can support
  transcription-associated condensate/scaffold behavior, but the conserved core role is activation
  and targeting of CDK9-dependent transcription elongation rather than general DNA binding
  or cell division.'
taxon:
  id: NCBITaxon:10090
  label: Mus musculus
existing_annotations:
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0032786
    label: positive regulation of DNA-templated transcription, elongation
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: The existing term is too broad or incorrectly framed for Cyclin T1.
    action: MODIFY
    reason: Cyclin T1 acts by activating/targeting CDK9 in P-TEFb for RNA polymerase II
      pause release, so the proposed replacement captures the mechanism more precisely.
    proposed_replacement_terms:
    - id: GO:0032968
      label: positive regulation of transcription elongation by RNA polymerase II
    supported_by:
    - reference_id: file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
      supporting_text: Cyclin T1 functions as the CDK9 cyclin partner in P-TEFb,
        enabling RNAPII transcriptional elongation by supporting phosphorylation events
        required for RNAPII pause release and productive elongation.
- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0061575
    label: cyclin-dependent protein serine/threonine kinase activator activity
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
    supported_by:
    - reference_id: file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
      supporting_text: The core P-TEFb heterodimer is CDK9-Cyclin T1. CDK9 is the
        catalytic kinase; Cyclin T1 is the cyclin subunit that enables CDK9 activity
        within transcriptional complexes.
- term:
    id: GO:0008024
    label: cyclin/CDK positive transcription elongation factor complex
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0006357
    label: regulation of transcription by RNA polymerase II
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: The existing term is too broad or incorrectly framed for Cyclin T1.
    action: MODIFY
    reason: Cyclin T1 acts by activating/targeting CDK9 in P-TEFb for RNA polymerase II
      pause release, so the proposed replacement captures the mechanism more precisely.
    proposed_replacement_terms:
    - id: GO:0032968
      label: positive regulation of transcription elongation by RNA polymerase II
- term:
    id: GO:0016538
    label: cyclin-dependent protein serine/threonine kinase regulator activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: The existing term is too broad or incorrectly framed for Cyclin T1.
    action: MODIFY
    reason: Cyclin T1 acts by activating/targeting CDK9 in P-TEFb for RNA polymerase II
      pause release, so the proposed replacement captures the mechanism more precisely.
    proposed_replacement_terms:
    - id: GO:0061575
      label: cyclin-dependent protein serine/threonine kinase activator activity
- term:
    id: GO:0051301
    label: cell division
  evidence_type: IEA
  original_reference_id: GO_REF:0000043
  review:
    summary: The annotation overstates direct DNA/cell-cycle function or uses vague
      binding.
    action: MARK_AS_OVER_ANNOTATED
    reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a
      general DNA-binding protein or independent cell-division factor.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:20434984
  review:
    summary: The annotation overstates direct DNA/cell-cycle function or uses vague
      binding.
    action: MARK_AS_OVER_ANNOTATED
    reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a
      general DNA-binding protein or independent cell-division factor.
    supported_by:
    - reference_id: PMID:20434984
      supporting_text: c-Myc regulates transcriptional pause release.
- term:
    id: GO:0005515
    label: protein binding
  evidence_type: IPI
  original_reference_id: PMID:22922464
  review:
    summary: The annotation overstates direct DNA/cell-cycle function or uses vague
      binding.
    action: MARK_AS_OVER_ANNOTATED
    reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a
      general DNA-binding protein or independent cell-division factor.
    supported_by:
    - reference_id: PMID:22922464
      supporting_text: Bromodomain-dependent stage-specific male genome programming by
        Brdt.
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0005654
    label: nucleoplasm
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0008024
    label: cyclin/CDK positive transcription elongation factor complex
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0032968
    label: positive regulation of transcription elongation by RNA polymerase II
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
    supported_by:
    - reference_id: file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
      supporting_text: Cyclin T1 functions as the CDK9 cyclin partner in P-TEFb,
        enabling RNAPII transcriptional elongation by supporting phosphorylation events
        required for RNAPII pause release and productive elongation.
- term:
    id: GO:0043923
    label: host-mediated activation of viral transcription
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported context-specific localization or viral co-option.
    action: KEEP_AS_NON_CORE
    reason: The annotation is biologically plausible but peripheral to the conserved
      P-TEFb transcription elongation function.
- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0061575
    label: cyclin-dependent protein serine/threonine kinase activator activity
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0070063
    label: RNA polymerase binding
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0070691
    label: P-TEFb complex
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
    supported_by:
    - reference_id: file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
      supporting_text: Mouse Ccnt1 encodes Cyclin T1, a nuclear cyclin-family
        regulatory subunit that forms P-TEFb with CDK9.
- term:
    id: GO:0097322
    label: 7SK snRNA binding
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0140297
    label: DNA-binding transcription factor binding
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0140693
    label: molecular condensate scaffold activity
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0003677
    label: DNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: The annotation overstates direct DNA/cell-cycle function or uses vague
      binding.
    action: MARK_AS_OVER_ANNOTATED
    reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a
      general DNA-binding protein or independent cell-division factor.
- term:
    id: GO:0005654
    label: nucleoplasm
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0008024
    label: cyclin/CDK positive transcription elongation factor complex
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0032968
    label: positive regulation of transcription elongation by RNA polymerase II
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0043923
    label: host-mediated activation of viral transcription
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported context-specific localization or viral co-option.
    action: KEEP_AS_NON_CORE
    reason: The annotation is biologically plausible but peripheral to the conserved
      P-TEFb transcription elongation function.
- term:
    id: GO:0045944
    label: positive regulation of transcription by RNA polymerase II
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0061575
    label: cyclin-dependent protein serine/threonine kinase activator activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0070063
    label: RNA polymerase binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0070691
    label: P-TEFb complex
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0097322
    label: 7SK snRNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0140297
    label: DNA-binding transcription factor binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0140693
    label: molecular condensate scaffold activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000107
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0005829
    label: cytosol
  evidence_type: ISO
  original_reference_id: GO_REF:0000119
  review:
    summary: Supported context-specific localization or viral co-option.
    action: KEEP_AS_NON_CORE
    reason: The annotation is biologically plausible but peripheral to the conserved
      P-TEFb transcription elongation function.
- term:
    id: GO:0032968
    label: positive regulation of transcription elongation by RNA polymerase II
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0070691
    label: P-TEFb complex
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0061575
    label: cyclin-dependent protein serine/threonine kinase activator activity
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0140693
    label: molecular condensate scaffold activity
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0019901
    label: protein kinase binding
  evidence_type: IDA
  original_reference_id: PMID:22547058
  review:
    summary: The cited paper does not support Ccnt1/CDK9 protein kinase binding.
    action: REMOVE
    reason: PMID:22547058 concerns cyclin K-containing CDK12/CDK13 complexes in mouse
      embryonic stem cells and states that cyclin K did not interact with CDK9 in cells.
      It should not be used to support a Ccnt1 protein kinase binding annotation.
    supported_by:
    - reference_id: PMID:22547058
      supporting_text: Cyclin K-containing kinase complexes maintain self-renewal in
        murine embryonic stem cells.
- term:
    id: GO:0097322
    label: 7SK snRNA binding
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0008024
    label: cyclin/CDK positive transcription elongation factor complex
  evidence_type: ISS
  original_reference_id: GO_REF:0000024
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
- term:
    id: GO:0003682
    label: chromatin binding
  evidence_type: IDA
  original_reference_id: PMID:18662700
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
    supported_by:
    - reference_id: PMID:18662700
      supporting_text: The positive transcription elongation factor b is an essential
        cofactor for the activation of transcription by myocyte enhancer factor 2.
- term:
    id: GO:0000976
    label: transcription cis-regulatory region binding
  evidence_type: IDA
  original_reference_id: PMID:20570862
  review:
    summary: The annotation overstates direct DNA/cell-cycle function or uses vague
      binding.
    action: MARK_AS_OVER_ANNOTATED
    reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a
      general DNA-binding protein or independent cell-division factor.
    supported_by:
    - reference_id: PMID:20570862
      supporting_text: Multiple functions of Ldb1 required for beta-globin activation
        during erythroid differentiation.
- term:
    id: GO:0008024
    label: cyclin/CDK positive transcription elongation factor complex
  evidence_type: TAS
  original_reference_id: PMID:20570862
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
    supported_by:
    - reference_id: PMID:20570862
      supporting_text: Multiple functions of Ldb1 required for beta-globin activation
        during erythroid differentiation.
- term:
    id: GO:0003677
    label: DNA binding
  evidence_type: ISO
  original_reference_id: PMID:16109376
  review:
    summary: The annotation overstates direct DNA/cell-cycle function or uses vague
      binding.
    action: MARK_AS_OVER_ANNOTATED
    reason: Cyclin T1 is recruited to transcriptional machinery rather than acting as a
      general DNA-binding protein or independent cell-division factor.
    supported_by:
    - reference_id: PMID:16109376
      supporting_text: The bromodomain protein Brd4 is a positive regulatory component
        of P-TEFb and stimulates RNA polymerase II-dependent transcription.
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IDA
  original_reference_id: PMID:16109376
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
    supported_by:
    - reference_id: PMID:16109376
      supporting_text: The bromodomain protein Brd4 is a positive regulatory component
        of P-TEFb and stimulates RNA polymerase II-dependent transcription.
- term:
    id: GO:0006468
    label: protein phosphorylation
  evidence_type: ISO
  original_reference_id: PMID:16109376
  review:
    summary: The existing term is too broad or incorrectly framed for Cyclin T1.
    action: MODIFY
    reason: Cyclin T1 acts by activating/targeting CDK9 in P-TEFb for RNA polymerase II
      pause release, so the proposed replacement captures the mechanism more precisely.
    proposed_replacement_terms:
    - id: GO:0061575
      label: cyclin-dependent protein serine/threonine kinase activator activity
    supported_by:
    - reference_id: PMID:16109376
      supporting_text: The bromodomain protein Brd4 is a positive regulatory component
        of P-TEFb and stimulates RNA polymerase II-dependent transcription.
- term:
    id: GO:0017069
    label: snRNA binding
  evidence_type: IDA
  original_reference_id: PMID:16109376
  review:
    summary: Supported P-TEFb regulatory function.
    action: ACCEPT
    reason: The term is consistent with Cyclin T1 as a CDK9 regulatory cyclin in P-TEFb
      that promotes RNA polymerase II transcription elongation and binds 7SK snRNA.
    supported_by:
    - reference_id: PMID:16109376
      supporting_text: The bromodomain protein Brd4 is a positive regulatory component
        of P-TEFb and stimulates RNA polymerase II-dependent transcription.
    - reference_id: file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
      supporting_text: A substantial fraction of P-TEFb is sequestered in an inactive
        ribonucleoprotein complex organized around 7SK snRNA, with protein components
        including HEXIM1/2, LARP7, and MePCE.
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO terms
  findings: []
- id: GO_REF:0000024
  title: Manual transfer of experimentally-verified manual GO annotation data to
    orthologs by curator judgment of sequence similarity
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000043
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
  findings: []
- id: GO_REF:0000107
  title: Automatic transfer of experimentally verified manual GO annotation data to
    orthologs using Ensembl Compara
  findings: []
- id: GO_REF:0000119
  title: Automated transfer of experimentally-verified manual GO annotation data to
    mouse-human orthologs
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []
- id: PMID:16109376
  title: The bromodomain protein Brd4 is a positive regulatory component of P-TEFb and
    stimulates RNA polymerase II-dependent transcription.
  findings: []
- id: PMID:18662700
  title: The positive transcription elongation factor b is an essential cofactor for the
    activation of transcription by myocyte enhancer factor 2.
  findings: []
- id: PMID:20434984
  title: c-Myc regulates transcriptional pause release.
  findings: []
- id: PMID:20570862
  title: Multiple functions of Ldb1 required for beta-globin activation during erythroid
    differentiation.
  findings: []
- id: PMID:22547058
  title: Cyclin K-containing kinase complexes maintain self-renewal in murine embryonic
    stem cells.
  findings: []
- id: PMID:22922464
  title: Bromodomain-dependent stage-specific male genome programming by Brdt.
  findings: []
- id: file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
  title: Falcon deep research synthesis for mouse Ccnt1
  findings:
  - statement: Cyclin T1 is the CDK9 regulatory cyclin in P-TEFb that promotes RNA
      polymerase II pause release and productive transcription elongation.
    supporting_text: Cyclin T1 functions as the CDK9 cyclin partner in P-TEFb, enabling
      RNAPII transcriptional elongation by supporting phosphorylation events required
      for RNAPII pause release and productive elongation.
core_functions:
- description: Cyclin T1 activates and recruits CDK9 as part of P-TEFb to stimulate RNA
    polymerase II transcription elongation.
  molecular_function:
    id: GO:0061575
    label: cyclin-dependent protein serine/threonine kinase activator activity
  directly_involved_in:
  - id: GO:0032968
    label: positive regulation of transcription elongation by RNA polymerase II
  locations:
  - id: GO:0005634
    label: nucleus
  - id: GO:0005654
    label: nucleoplasm
  in_complex:
    id: GO:0070691
    label: P-TEFb complex
  supported_by:
  - reference_id: file:mouse/Ccnt1/Ccnt1-uniprot.txt
    supporting_text: Regulatory subunit of the cyclin-dependent kinase pair
  - reference_id: file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
    supporting_text: Cyclin T1 functions as the CDK9 cyclin partner in P-TEFb, enabling
      RNAPII transcriptional elongation by supporting phosphorylation events required
      for RNAPII pause release and productive elongation.
  - reference_id: file:mouse/Ccnt1/Ccnt1-deep-research-falcon.md
    supporting_text: Mouse Ccnt1 encodes Cyclin T1, a nuclear cyclin-family regulatory
      subunit that forms P-TEFb with CDK9.