RCO1

Existing Annotations Review

Gene Description

Existing Annotations Review

Core Functions

References

Deep Research

Falcon

Perplexity

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GO Term	Evidence	Action	Reason
GO:0006357 regulation of transcription by RNA polymerase II	IBA GO_REF:0000033	MODIFY	Summary: IBA annotation inferred through phylogenetic analysis. RCO1 is an essential subunit of the Rpd3S histone deacetylase complex, which regulates transcription through deacetylation of histone tails in gene bodies. However, this annotation is indirect - RCO1 does not directly regulate RNAP II; it rather modifies chromatin structure that influences transcription. The term is too general and does not capture the specific mechanism of cryptic transcription suppression. Reason: This annotation correctly captures that RCO1 participates in transcriptional regulation, but the term "regulation of transcription by RNA polymerase II" is too broad and imprecise. RCO1's primary function is not to regulate RNAP II itself, but rather to suppress cryptic transcription initiation within gene bodies through H3K36me-targeted nucleosome deacetylation (where the H3K36me3 mark is read by the Eaf3 chromodomain, while RCO1's PHD fingers read the unmodified H3 tail / H3K4me0). More specific annotations like "transcription elongation-coupled chromatin remodeling" (GO:0140673) or "positive regulation of transcription by RNA polymerase II" would be more accurate given RCO1's involvement in maintaining productive transcription by preventing spurious internal initiation. Proposed replacements: chromatin organization negative regulation of antisense RNA transcription Supporting Evidence: file:yeast/RCO1/RCO1-deep-research-perplexity.md The primary biological function of the Rpd3S complex, which depends critically on proper Rco1 function, is to suppress the initiation of cryptic transcripts that would otherwise initiate from internal promoters within the bodies of actively transcribed genes file:yeast/RCO1/RCO1-deep-research-falcon.md Rpd3S is a histone deacetylase complex that operates co-transcriptionally across coding regions (ORFs/gene bodies) to remove histone acetylation “in the wake” of RNA polymerase II (Pol II), thereby suppressing cryptic (spurious intragenic) transcription initiation. Rco1 is one of the Rpd3S-specific subunits underlying this gene-body surveillance function.
GO:0032221 Rpd3S complex	IBA GO_REF:0000033	ACCEPT	Summary: RCO1 is a core component of the Rpd3S histone deacetylase complex. UniProt explicitly states that RCO1 is a "Component of the RPD3C(S) complex composed of at least EAF3, RCO1, RPD3, SIN3, and UME1". RCO1 exists as a homodimer within this complex and is essential for Rpd3S assembly and function. This is one of the most precisely annotated functions. Reason: Excellent annotation. RCO1 is directly identified as a structural component of the Rpd3S complex (CPX-1851) through both direct experimental evidence (IDA annotations from PMID:16286007 and PMID:16286008) and phylogenetic inference (IBA). This is a core, defining function of RCO1. Supporting Evidence: file:yeast/RCO1/RCO1-uniprot.txt Component of the RPD3C(S) complex composed of at least EAF3, RCO1, RPD3, SIN3, and UME1. [ECO:0000269\|PubMed:16286008] file:yeast/RCO1/RCO1-deep-research-perplexity.md RCO1 is a 684-amino acid transcriptional regulatory protein in the model organism Saccharomyces cerevisiae that functions as an essential subunit of the Rpd3S histone deacetylase (HDAC) complex file:yeast/RCO1/RCO1-deep-research-falcon.md Rpd3S is classically described as a five-subunit complex (Rpd3, Sin3, Ume1, Eaf3, Rco1). Mechanistic work shows Rco1 is a critical interaction hub: Rco1 forms key contacts with Eaf3 (via a Sin3 interaction domain/SID interacting with Eaf3’s MRG domain) and is required for full Rpd3S nucleosome engagement and cryptic transcription suppression.
GO:0005634 nucleus	IEA GO_REF:0000044	ACCEPT	Summary: RCO1 is a nuclear protein. The UniProt record explicitly states "SUBCELLULAR LOCATION: Nucleus {ECO:0000269\|PubMed:14562095}". This is a well-established subcellular localization supported by large-scale proteomics analysis. Reason: This is a correct and unambiguous annotation. RCO1 functions exclusively in the nucleus as part of the Rpd3S complex. The IEA evidence from UniProtKB subcellular location mapping is appropriate and is backed by experimental evidence (HDA from PMID:14562095 and NAS from PMID:9512514). Supporting Evidence: PMID:14562095 Global analysis of protein localization in budding yeast
GO:0006325 chromatin organization	IEA GO_REF:0000043	ACCEPT	Summary: RCO1 is involved in chromatin organization as a core component of the Rpd3S histone deacetylase complex. The complex deacetylates histones in gene bodies and works with linker histone Hho1 to maintain chromatin compaction and prevent nucleosome eviction. This is appropriately classified as a chromatin organization function. Reason: This annotation is correct. RCO1's primary role is chromatin organization through nucleosome deacetylation and cryptic transcription suppression. The IEA mapping from UniProtKB keywords is appropriate. Supporting evidence includes both the structural role in Rpd3S and the functional requirement for maintaining proper chromatin state in gene bodies. Supporting Evidence: file:yeast/RCO1/RCO1-deep-research-perplexity.md Cryo-EM structures of Rpd3S bound to nucleosome core particles have revealed multiple distinct functional states of the complex that shed light on how it achieves efficient deacetylation while also reorganizing chromatin structure file:yeast/RCO1/RCO1-deep-research-falcon.md Rpd3S is a histone deacetylase complex that operates co-transcriptionally across coding regions (ORFs/gene bodies) to remove histone acetylation “in the wake” of RNA polymerase II (Pol II), thereby suppressing cryptic (spurious intragenic) transcription initiation. Rco1 is one of the Rpd3S-specific subunits underlying this gene-body surveillance function.
GO:0006351 DNA-templated transcription	IEA GO_REF:0000043	KEEP AS NON CORE	Summary: RCO1 indirectly influences DNA-templated transcription by maintaining proper chromatin structure and suppressing cryptic transcription initiation within gene bodies. However, this is an indirect effect mediated through chromatin modification rather than direct participation in the transcription machinery. The annotation is too general. Reason: While RCO1 does influence transcription through its chromatin regulatory functions, it is not directly involved in DNA-templated transcription. Its effect is indirect - it modifies chromatin structure to prevent inappropriate transcription initiation. More specific terms like "chromatin organization" or "negative regulation of transcription, chromatin-dependent" would be more accurate. This should be marked as a non-core function since RCO1's direct function is chromatin modification, not transcription execution. Supporting Evidence: file:yeast/RCO1/RCO1-deep-research-perplexity.md The mechanism by which this suppression occurs involves the coordinated action of Set2 methylation and Rpd3S deacetylation to maintain a hypoacetylated chromatin state over gene bodies
GO:0008270 zinc ion binding	IEA GO_REF:0000043	ACCEPT	Summary: RCO1 contains two PHD (plant homeobox) zinc finger domains (residues 260-309 and 414-472) that coordinate zinc ions as structural cofactors. The UniProt record explicitly identifies these ZN_FING features with PHD-type zinc fingers. Zinc binding is essential for the structural integrity and function of the PHD domains. Reason: This annotation is correct. RCO1 contains two PHD zinc finger motifs that require coordinated zinc ions for proper folding and function. The IEA evidence from UniProtKB keyword mapping is appropriate. Zinc ion binding is a structural requirement for RCO1's histone mark recognition capability. This is well-supported by the protein domain annotations and structural studies showing the importance of the PHD zinc fingers in nucleosome binding. Supporting Evidence: file:yeast/RCO1/RCO1-uniprot.txt ZN_FING 260..309 /note="PHD-type 1" and ZN_FING 414..472 /note="PHD-type 2" file:yeast/RCO1/RCO1-deep-research-perplexity.md RCO1 contains several critical domains including a plant homeobox (PHD) domain and a Sin3-interacting domain (SID), which together orchestrate the recognition of nucleosomes methylated at histone H3 lysine 36 file:yeast/RCO1/RCO1-deep-research-falcon.md Rco1 contains two plant homeodomain (PHD) zinc-finger modules (PHD1 and PHD2). Biochemical evidence indicates that both PHD1 and PHD2 bind the extreme N-terminus of histone H3 (H3 1–20) and that H3K4 trimethylation reduces binding—a mechanism that helps restrict Rpd3S away from promoter nucleosomes enriched in H3K4me3.
GO:0046872 metal ion binding	IEA GO_REF:0000043	KEEP AS NON CORE	Summary: RCO1 contains metal-binding zinc finger domains, making metal ion binding a valid annotation. However, the more specific zinc ion binding (GO:0008270) is already annotated and is more informative. Reason: This is technically correct but overly general. RCO1 does bind metal ions (specifically zinc), but the more specific and informative annotation GO:0008270 (zinc ion binding) is already present. The broader metal ion binding term should be marked as non-core since zinc ion binding is the specific and functionally important metal-binding activity. This is a parent term that is less informative than the specific zinc annotation. Supporting Evidence: file:yeast/RCO1/RCO1-uniprot.txt Metal-binding; Zinc-finger keywords; ZN_FING features indicating zinc coordination
GO:0005515 protein binding	IPI PMID:15766533 Navigating the chaperone network: an integrative map of phys...	KEEP AS NON CORE	Summary: RCO1 interacts with multiple protein partners including Hsp90 chaperone, Rpd3, Sin3, Ume1, Eaf3, and other complex members. Multiple IPI annotations from co-immunoprecipitation studies demonstrate protein-protein interactions. However, "protein binding" is an uninformative molecular function term that does not describe the specific binding interactions or their biological significance. The specific interaction partners and complexes are already captured by other annotations (Rpd3S complex membership). Reason: While RCO1 does bind proteins (as documented by multiple IPI studies from PMIDs 15766533, 16429126, 16554755, 17101441, 19536198, 21179020, 23878396, 24843044, and 37968396), the term "protein binding" is too generic and uninformative. It does not distinguish between interaction partners or provide functional context. The specific interactions that matter - with Rpd3S complex subunits (Rpd3, Sin3, Ume1, Eaf3) - are already captured by the "part_of: Rpd3S complex" annotation. Additional specific partners like chaperones may be captured in separate annotations. This annotation should be marked non-core as it provides minimal functional information compared to complex membership annotations. Supporting Evidence: PMID:15766533 Navigating the chaperone network: an integrative map of physical and genetic interactions mediated by the hsp90 chaperone PMID:16554755 Global landscape of protein complexes in the yeast Saccharomyces cerevisiae file:yeast/RCO1/RCO1-deep-research-perplexity.md Rco1 functions as a critical interaction hub that coordinates multiple layers of complex assembly and function
GO:0005515 protein binding	IPI PMID:16429126 Proteome survey reveals modularity of the yeast cell machine...	KEEP AS NON CORE	Summary: Multiple IPI annotations document RCO1 protein binding interactions from proteome-wide studies. Reason: Generic "protein binding" annotation - refer to primary PMID:15766533 review for rationale. All protein binding annotations share the same issue: too generic without functional context. Supporting Evidence: PMID:16429126 Proteome survey reveals modularity of the yeast cell machinery
GO:0005515 protein binding	IPI PMID:16554755 Global landscape of protein complexes in the yeast Saccharom...	KEEP AS NON CORE	Summary: Multiple IPI annotations document RCO1 protein binding interactions from proteome-wide studies. Reason: Generic "protein binding" annotation - refer to primary PMID:15766533 review for rationale. Supporting Evidence: PMID:16554755 Global landscape of protein complexes in the yeast Saccharomyces cerevisiae
GO:0005515 protein binding	IPI PMID:17101441 Analyzing chromatin remodeling complexes using shotgun prote...	KEEP AS NON CORE	Summary: Multiple IPI annotations document RCO1 protein binding interactions from proteome-wide studies. Reason: Generic "protein binding" annotation - refer to primary PMID:15766533 review for rationale. Supporting Evidence: PMID:17101441 Analyzing chromatin remodeling complexes using shotgun proteomics
GO:0005515 protein binding	IPI PMID:19536198 An atlas of chaperone-protein interactions in Saccharomyces ...	KEEP AS NON CORE	Summary: Multiple IPI annotations document RCO1 protein binding interactions from proteome-wide studies. Reason: Generic "protein binding" annotation - refer to primary PMID:15766533 review for rationale. Supporting Evidence: PMID:19536198 An atlas of chaperone-protein interactions in Saccharomyces cerevisiae
GO:0005515 protein binding	IPI PMID:21179020 Defining the budding yeast chromatin-associated interactome.	KEEP AS NON CORE	Summary: Multiple IPI annotations document RCO1 protein binding interactions from proteome-wide studies. Reason: Generic "protein binding" annotation - refer to primary PMID:15766533 review for rationale. Supporting Evidence: PMID:21179020 Defining the budding yeast chromatin-associated interactome
GO:0005515 protein binding	IPI PMID:23878396 The yeast Snt2 protein coordinates the transcriptional respo...	KEEP AS NON CORE	Summary: Multiple IPI annotations document RCO1 protein binding interactions from proteome-wide studies. Reason: Generic "protein binding" annotation - refer to primary PMID:15766533 review for rationale. Supporting Evidence: PMID:23878396 The yeast Snt2 protein coordinates the transcriptional response to hydrogen peroxide-mediated oxidative stress
GO:0005515 protein binding	IPI PMID:24843044 Eaf5/7/3 form a functionally independent NuA4 submodule link...	KEEP AS NON CORE	Summary: Multiple IPI annotations document RCO1 protein binding interactions from proteome-wide studies. Reason: Generic "protein binding" annotation - refer to primary PMID:15766533 review for rationale. Supporting Evidence: PMID:24843044 Eaf5/7/3 form a functionally independent NuA4 submodule linked to RNA polymerase II-coupled nucleosome recycling
GO:0005515 protein binding	IPI PMID:37968396 The social and structural architecture of the yeast protein ...	KEEP AS NON CORE	Summary: Multiple IPI annotations document RCO1 protein binding interactions from proteome-wide studies. Reason: Generic "protein binding" annotation - refer to primary PMID:15766533 review for rationale. Supporting Evidence: PMID:37968396 The social and structural architecture of the yeast protein interactome
GO:0000122 negative regulation of transcription by RNA polymerase II	NAS PMID:9512514 Histone deacetylase activity of Rpd3 is important for transc...	KEEP AS NON CORE	Summary: RCO1 is part of the Rpd3S complex, which suppresses cryptic transcription initiation within gene bodies. This represents negative regulation of transcription at internal promoters. However, the evidence is NAS (derived from ComplexPortal annotation), indicating this is a statement from the literature without direct experimental evidence in the cited paper. Reason: The annotation is mechanistically correct - Rpd3S does negatively regulate transcription by suppressing cryptic initiation. However, RCO1's specific role is in H3K4me0 / unmodified-H3 recognition (via its PHD fingers) and complex assembly, not direct transcription regulation (recognition of H3K36me3 is contributed by the Eaf3 chromodomain). The negative regulation is a consequence of chromatin organization. The more specific and core function is "negative regulation of antisense RNA transcription" (GO:0060195), which better captures RCO1's role in maintaining promoter directionality. This broader annotation should be marked non-core. Supporting Evidence: PMID:9512514 Histone deacetylase activity of Rpd3 is important for transcriptional repression in vivo file:yeast/RCO1/RCO1-deep-research-falcon.md Rpd3S is a histone deacetylase complex that operates co-transcriptionally across coding regions (ORFs/gene bodies) to remove histone acetylation “in the wake” of RNA polymerase II (Pol II), thereby suppressing cryptic (spurious intragenic) transcription initiation. Rco1 is one of the Rpd3S-specific subunits underlying this gene-body surveillance function.
GO:0005634 nucleus	NAS PMID:9512514 Histone deacetylase activity of Rpd3 is important for transc...	ACCEPT	Summary: This is a duplicate nucleus annotation from NAS evidence (literature statement). The HDA annotation from PMID:14562095 is more direct. Reason: Correct annotation. RCO1 is a nuclear protein. This NAS entry documents nucleus localization from literature. While the HDA annotation from PMID:14562095 is more direct, both are correct. Supporting Evidence: PMID:9512514 Histone deacetylase activity of Rpd3 is important for transcriptional repression in vivo
GO:0006334 nucleosome assembly	NAS PMID:22177115 The Rpd3 core complex is a chromatin stabilization module.	KEEP AS NON CORE	Summary: The Rpd3 core complex is described as a "chromatin stabilization module" that maintains nucleosome integrity and prevents nucleosome eviction. This could be interpreted as related to nucleosome assembly, though it is more accurately described as nucleosome maintenance and stabilization. Reason: RCO1's role is chromatin stabilization and nucleosome maintenance, not nucleosome assembly per se. The term "nucleosome assembly" typically refers to the assembly of nucleosome core particles from histone proteins and DNA, which is not RCO1's primary function. RCO1 maintains existing nucleosomes and prevents their disruption during transcription. The term "chromatin organization" (GO:0006325) is more appropriate. This annotation should be marked non-core. Supporting Evidence: PMID:22177115 The Rpd3 core complex is a chromatin stabilization module
GO:0008270 zinc ion binding	RCA PMID:30358795 The cellular economy of the Saccharomyces cerevisiae zinc pr...	ACCEPT	Summary: This is a second annotation for zinc ion binding, now with RCA (Review-based annotation from Curated Review) evidence, citing a paper on "The cellular economy of the Saccharomyces cerevisiae zinc proteome". This complements the IEA zinc binding annotation. Reason: This is a high-quality RCA annotation documenting zinc ion binding through curated review. RCO1 contains two PHD zinc finger domains that require zinc coordination. Having both IEA and RCA evidence strengthens the annotation. This is a core structural feature of RCO1. Supporting Evidence: PMID:30358795 The cellular economy of the Saccharomyces cerevisiae zinc proteome
GO:0045944 positive regulation of transcription by RNA polymerase II	IMP PMID:24358376 The roles of the catalytic and noncatalytic activities of Rp...	ACCEPT	Summary: RCO1 is required for maintaining transcription of many genes by suppressing cryptic transcription and maintaining productive transcription elongation. Deletion of rco1 causes reduction in expression of many genes and activation of cryptic transcripts. This could be viewed as RCO1 positively regulating transcription of main promoter transcripts. Reason: This IMP annotation is well-supported. RCO1 deletion causes cryptic transcription activation and reduction in proper transcript production, demonstrating that RCO1 is required for positive regulation of productive transcription. The paper "The roles of the catalytic and noncatalytic activities of Rpd3L and Rpd3S in the regulation of gene transcription in yeast" directly addresses this. RCO1 enables productive transcription by suppressing spurious internal initiation. Supporting Evidence: PMID:24358376 The roles of the catalytic and noncatalytic activities of Rpd3L and Rpd3S in the regulation of gene transcription in yeast
GO:0005634 nucleus	HDA PMID:14562095 Global analysis of protein localization in budding yeast.	ACCEPT	Summary: RCO1 is a nuclear protein, determined by large-scale proteomics analysis of protein localization. This HDA annotation represents direct experimental evidence of nuclear localization. Within the nucleus, Rco1 is predominantly chromatin-associated and localized to active ORFs/gene bodies. Reason: Excellent annotation. HDA evidence from PMID:14562095 (large-scale protein localization analysis) directly documents RCO1's nuclear localization. This is one of the foundational observations about RCO1. Falcon deep research further specifies that within the nucleus Rco1 is predominantly in the chromatin fraction at active gene bodies, consistent with its co-transcriptional Rpd3S role. Supporting Evidence: PMID:14562095 Global analysis of protein localization in budding yeast file:yeast/RCO1/RCO1-deep-research-falcon.md Rco1 is predominantly chromatin-associated and localizes to active ORFs / gene bodies rather than promoters, consistent with Rpd3S function in transcribed coding regions. Fractionation studies place wild-type Rco1 mainly in the chromatin fraction.
GO:0000118 histone deacetylase complex	IDA PMID:16286008 Cotranscriptional set2 methylation of histone H3 lysine 36 r...	ACCEPT	Summary: RCO1 is an identified component of the histone deacetylase complex through direct experimental evidence (immunoprecipitation and mass spectrometry). This directly identifies RCO1 as part of a HDAC complex, which is the broader complex category. Reason: Excellent IDA annotation. RCO1 was directly identified as a component of the histone deacetylase complex through the landmark Keogh et al. (2005) paper that characterized the Rpd3S complex composition. This is a core structural annotation. The paper demonstrates RCO1's direct role in the Rpd3 histone deacetylase complex. Supporting Evidence: PMID:16286008 Cotranscriptional set2 methylation of histone H3 lysine 36 recruits a repressive Rpd3 complex file:yeast/RCO1/RCO1-deep-research-falcon.md RCO1 encodes Rco1, a non-catalytic chromatin regulatory protein. It is not itself a histone deacetylase; rather, it is a reader/targeting and regulatory subunit required for proper activity and chromatin engagement of the Rpd3S (Rpd3 small) HDAC complex.
GO:0006368 transcription elongation by RNA polymerase II	IGI PMID:19948887 Histone H3K4 and K36 methylation, Chd1 and Rpd3S oppose the ...	KEEP AS NON CORE	Summary: RCO1 participates in transcription elongation through its role in chromatin organization and preventing transcription disruption during elongation. The IGI evidence shows genetic interaction with Spt4-Spt5 factors that regulate elongation. However, RCO1's role is indirect - through chromatin modification rather than direct elongation machinery interaction. Reason: RCO1 supports transcription elongation indirectly by maintaining proper chromatin structure and preventing nucleosome disruption during polymerase transit. However, its primary function is not elongation per se, but rather preventing cryptic transcription through chromatin organization. The "positive regulation of transcription by RNA polymerase II" annotation better captures RCO1's more direct role. This elongation annotation should be marked non-core as it represents an indirect consequence of RCO1's chromatin regulatory function. Supporting Evidence: PMID:19948887 Histone H3K4 and K36 methylation, Chd1 and Rpd3S oppose the functions of Saccharomyces cerevisiae Spt4-Spt5 in transcription
GO:0030174 regulation of DNA-templated DNA replication initiation	IMP PMID:19417103 Genome-wide replication profiles indicate an expansive role ...	KEEP AS NON CORE	Summary: RCO1 (as part of Rpd3S) affects DNA replication timing and initiation frequency through chromatin regulation. The paper "Genome-wide replication profiles indicate an expansive role for Rpd3L in regulating replication initiation timing or efficiency" shows Rpd3L and Rpd3S influence replication through chromatin state. However, this is an indirect effect mediated through chromatin organization, not direct replication machinery interaction. Reason: RCO1 influences DNA replication timing indirectly through its role in chromatin organization and gene expression regulation. This is not a core function of RCO1. The primary function is cryptic transcription suppression and chromatin organization during transcription. Replication effects are pleiotropic consequences of altered chromatin state. This annotation should be marked non-core. Supporting Evidence: PMID:19417103 Genome-wide replication profiles indicate an expansive role for Rpd3L in regulating replication initiation timing or efficiency
GO:0032221 Rpd3S complex	IDA PMID:16286007 Histone H3 methylation by Set2 directs deacetylation of codi...	ACCEPT	Summary: RCO1 is directly identified as a component of the Rpd3S complex through co-immunoprecipitation and mass spectrometry. Two separate papers (PMID:16286007 and PMID:16286008) both identify RCO1 in Rpd3S, representing independent confirmation. Reason: Excellent IDA annotation. RCO1 is directly identified as a core component of Rpd3S in the landmark papers describing the complex composition. This is a foundational structural and functional annotation. Both PMID:16286007 and PMID:16286008 provide direct experimental evidence (IP-MS). Supporting Evidence: PMID:16286007 Histone H3 methylation by Set2 directs deacetylation of coding regions by Rpd3S to suppress spurious intragenic transcription
GO:0032221 Rpd3S complex	IDA PMID:16286008 Cotranscriptional set2 methylation of histone H3 lysine 36 r...	ACCEPT	Summary: RCO1 is directly identified as a component of the Rpd3S complex through co-immunoprecipitation. This is a second IDA annotation from independent confirmation in PMID:16286008. Reason: Excellent IDA annotation from a second independent source. Duplicate annotations with different PMIDs represent important independent confirmation of RCO1's role as a core Rpd3S component. Supporting Evidence: PMID:16286008 Cotranscriptional set2 methylation of histone H3 lysine 36 recruits a repressive Rpd3 complex
GO:0060195 negative regulation of antisense RNA transcription	IMP PMID:21248844 Nascent transcript sequencing visualizes transcription at nu...	ACCEPT	Summary: RCO1 deletion increases antisense transcription from promoters positioned opposite the 3' ends of genes. This represents RCO1's role in maintaining promoter directionality and preventing spurious antisense transcription initiation. This is one of RCO1's most important and specific functions. Reason: Excellent IMP annotation capturing one of RCO1's most important and specific functions. Nascent transcript sequencing clearly shows that rco1 deletion causes derepression of antisense transcription at 3' gene ends, indicating RCO1 enforces transcriptional directionality through chromatin modification. This is more specific and mechanistically informative than broader "negative regulation of transcription" terms. This is a CORE function of RCO1. Supporting Evidence: PMID:21248844 Nascent transcript sequencing visualizes transcription at nucleotide resolution file:yeast/RCO1/RCO1-deep-research-perplexity.md deletion of rco1 increases antisense transcription originating from antisense promoters positioned opposite the 3' ends of genes