id: P47927
gene_symbol: AP2
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:3702
  label: Arabidopsis thaliana
description: >-
  APETALA2 (AP2; At4g36920; UniProt P47927) encodes a nuclear AP2/ERF-family
  DNA-binding transcription factor with two AP2/ERF DNA-binding domains and an
  EAR repression motif. AP2 is a canonical Arabidopsis A-class floral homeotic
  regulator that controls floral meristem and perianth organ identity, restricts
  floral homeotic gene expression, contributes to shoot meristem maintenance and
  floral-transition morphology, and regulates seed and ovule/seed-coat
  development. The best-supported molecular function is cis-regulatory DNA
  binding coupled to context-dependent transcriptional activation and repression;
  AP2 is post-transcriptionally restricted by miR172 and can repress targets
  through TOPLESS/HDA19-associated chromatin mechanisms. PANTHER places AP2 in
  family PTHR32467 (AP2-like ethylene-responsive transcription factor) and
  subfamily PTHR32467:SF142 (floral homeotic protein APETALA 2), consistent with
  conserved AP2/ERF transcription-factor function.
existing_annotations:
- term:
    id: GO:0005667
    label: transcription regulator complex
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      AP2 can act in transcriptional regulatory assemblies, including reported
      interactions with TOPLESS/HDA19 and MYBL2-containing regulatory complexes,
      so the broad component annotation is biologically plausible. However, the
      current IBA term is generic and does not describe AP2's core independently
      enabled activity, which is DNA-binding transcription factor activity.
    action: KEEP_AS_NON_CORE
    reason: >-
      Retain as a non-core cellular-component context. AP2 participates in
      transcriptional regulatory complexes, but the annotation is broad and should
      not substitute for the core AP2/ERF DNA-binding transcription factor
      activity and nuclear cis-regulatory DNA-binding annotations.
    supported_by:
    - reference_id: file:ARATH/AP2/AP2-uniprot.txt
      supporting_text: "Interacts with HDA19 and with TPL in an EAR-motif dependent manner"
    - reference_id: file:ARATH/AP2/AP2-deep-research-falcon.md
      supporting_text: "AP2 represses boundaries of multiple floral organ identity genes, including **AG, AP3, PI, SEP3**) by recruiting the co-repressor **TOPLESS (TPL)** and **HDA19**"
- term:
    id: GO:0006355
    label: regulation of DNA-templated transcription
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  review:
    summary: >-
      This broad transcriptional-regulation process is consistent with AP2's
      conserved AP2/ERF transcription-factor family membership and direct
      AP2-specific literature showing target activation and repression.
    action: ACCEPT
    reason: >-
      AP2's central function is regulation of gene expression through promoter
      binding. The generic BP term is broad but accurate because AP2 has both
      activating and repressing target outputs, making a single positive or
      negative regulation term insufficient for the whole protein.
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "APETALA2 (AP2) plays a central role in the establishment of the floral meristem, the specification of floral organ identity, and the regulation of floral homeotic gene expression in Arabidopsis."
    - reference_id: file:ARATH/AP2/AP2-deep-research-falcon.md
      supporting_text: "AP2 is described as a multifunctional **transcription factor** controlling developmental transitions and organ identity, with experimentally supported **dual molecular roles** (activation and repression)."
- term:
    id: GO:0003677
    label: DNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      The InterPro-derived DNA-binding annotation is directionally correct
      because AP2 contains AP2/ERF DNA-binding domains, but the term is too
      generic for a well-characterized sequence-specific transcription factor.
    action: MODIFY
    reason: >-
      Replace generic DNA binding with terms that capture AP2's actual molecular
      role: a DNA-binding transcription factor that binds transcriptional
      cis-regulatory regions.
    proposed_replacement_terms:
    - id: GO:0003700
      label: DNA-binding transcription factor activity
    - id: GO:0000976
      label: transcription cis-regulatory region binding
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "We isolated the AP2 gene and found that it encodes a putative nuclear protein that is distinguished by an essential 68-amino acid repeated motif, the AP2 domain."
    - reference_id: file:ARATH/AP2/AP2-deep-research-falcon.md
      supporting_text: "Molecular function: AP2-domain transcription factor; binds thousands of genomic loci; functions as activator and repressor depending on target and tissue."
- term:
    id: GO:0003677
    label: DNA binding
  evidence_type: IEA
  original_reference_id: GO_REF:0000117
  review:
    summary: >-
      The ARBA DNA-binding annotation is correct at a high level but
      under-specific for AP2. The AP2 literature supports DNA-binding
      transcription factor activity and cis-regulatory region binding rather
      than undifferentiated DNA binding.
    action: MODIFY
    reason: >-
      Replace generic DNA binding with AP2's more informative transcription
      factor and promoter/cis-regulatory binding activities.
    proposed_replacement_terms:
    - id: GO:0003700
      label: DNA-binding transcription factor activity
    - id: GO:0000976
      label: transcription cis-regulatory region binding
    supported_by:
    - reference_id: file:ARATH/AP2/AP2-uniprot.txt
      supporting_text: "DNA_BIND        131..187"
    - reference_id: file:ARATH/AP2/AP2-uniprot.txt
      supporting_text: "DNA_BIND        223..280"
    - reference_id: file:ARATH/AP2/AP2-deep-research-falcon.md
      supporting_text: "AP2-domain transcription factor; binds thousands of genomic loci"
- term:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      AP2 contains two AP2/ERF DNA-binding domains and is a well-established
      transcription factor. Although this particular annotation is electronic,
      it is strongly corroborated by mutant, expression, direct-target, and
      family evidence.
    action: ACCEPT
    reason: >-
      The term accurately represents AP2's core molecular activity.
    supported_by:
    - reference_id: PMID:15708976
      supporting_text: "Arabidopsis APETALA2 ( AP2 ) encodes a member of the AP2/EREBP (ethylene responsive element binding protein) class of transcription factors"
    - reference_id: file:interpro/panther/PTHR32467/PTHR32467-entries.csv
      supporting_text: "P47927,Floral homeotic protein APETALA 2,protein,3702,Arabidopsis thaliana,Arabidopsis thaliana (Mouse-ear cress),AP2,432,PTHR32467:SF142,FLORAL HOMEOTIC PROTEIN APETALA 2,True"
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  review:
    summary: >-
      AP2 is annotated by UniProt as nuclear and contains a predicted nuclear
      localization signal. Independent functional evidence for DNA binding and
      transcriptional regulation also places AP2's active site of function in
      the nucleus.
    action: ACCEPT
    reason: >-
      Nucleus is the appropriate cellular location for AP2's DNA-binding
      transcription-factor activity. The direct cached literature mostly states
      this as predicted or functional inference rather than standalone imaging,
      but the localization is strongly supported by the protein's activity and
      UniProt annotation.
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "We isolated the AP2 gene and found that it encodes a putative nuclear protein"
    - reference_id: file:ARATH/AP2/AP2-uniprot.txt
      supporting_text: "SUBCELLULAR LOCATION: Nucleus"
- term:
    id: GO:0006355
    label: regulation of DNA-templated transcription
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: >-
      The InterPro-derived process annotation follows from AP2/ERF
      transcription-factor family membership and is supported by AP2-specific
      evidence for direct gene regulation.
    action: ACCEPT
    reason: >-
      This broad BP term is correct for AP2 because AP2 directly regulates
      transcriptional targets in floral meristems, shoot meristems, and seed
      tissues.
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "the regulation of floral homeotic gene expression in Arabidopsis"
    - reference_id: file:ARATH/AP2/AP2-deep-research-falcon.md
      supporting_text: "AP2 can **directly induce** some genes (e.g., **AGL15**) while **directly repressing** others (e.g., **SOC1**)."
- term:
    id: GO:0000976
    label: transcription cis-regulatory region binding
  evidence_type: IPI
  original_reference_id: PMID:25533953
  review:
    summary: >-
      The 2015 secondary cell wall network paper used yeast one-hybrid assays
      to map Arabidopsis transcription-factor binding to promoter fragments.
      The cached main text supports the assay framework but does not expose the
      AP2-specific supplementary row; nevertheless, AP2-specific ChIP and target
      evidence in the deep research independently supports the same term.
    action: ACCEPT
    reason: >-
      The term is an appropriate molecular-function annotation for AP2. The
      original high-throughput source should be treated as supporting network
      evidence, while AP2-specific direct-target studies provide the stronger
      biological justification.
    supported_by:
    - reference_id: PMID:25533953
      supporting_text: "Promoter sequences were screened using an enhanced yeast one hybrid (Y1H) assay against 467 (89%) of root xylem-expressed transcription factors"
    - reference_id: file:ARATH/AP2/AP2-deep-research-falcon.md
      supporting_text: "Genome-wide direct targeting (Plant Cell 2010). AP2 ChIP-seq identified extensive binding: **2,275** bound regions"
- term:
    id: GO:0000976
    label: transcription cis-regulatory region binding
  evidence_type: IPI
  original_reference_id: PMID:30356219
  review:
    summary: >-
      The 2018 nitrogen-associated network paper is cached only as abstract text,
      so the AP2-specific interaction table cannot be verified here. The term is
      still correct for AP2 based on independent AP2-specific promoter-binding
      and ChIP-seq evidence summarized in the deep research.
    action: ACCEPT
    reason: >-
      Accept the term, while noting the evidence limitation: the cached
      PMID:30356219 record does not contain the AP2-specific binding result.
      Independent direct AP2 evidence supports cis-regulatory region binding.
    supported_by:
    - reference_id: PMID:30356219
      supporting_text: "transcription factors that regulate the architecture of root and shoot systems"
    - reference_id: file:ARATH/AP2/AP2-deep-research-falcon.md
      supporting_text: "AP2 directly binds the SOC1 promoter and represses SOC1 in vegetative SAM"
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: ISM
  original_reference_id: GO_REF:0000122
  review:
    summary: >-
      The AtSubP prediction is consistent with UniProt's nuclear localization
      annotation, AP2's NLS, and the protein's DNA-binding transcription-factor
      function.
    action: ACCEPT
    reason: >-
      Nucleus is the correct location for AP2's core transcriptional regulatory
      activity.
    supported_by:
    - reference_id: file:ARATH/AP2/AP2-uniprot.txt
      supporting_text: "MOTIF           119..128"
    - reference_id: file:ARATH/AP2/AP2-uniprot.txt
      supporting_text: "Nuclear localization signal"
- term:
    id: GO:0010093
    label: specification of floral organ identity
  evidence_type: IMP
  original_reference_id: PMID:2535466
  review:
    summary: >-
      The classic floral homeotic mutant analysis showed that apetala2-1
      transforms first- and second-whorl organs and that wild-type AP2 acts at
      primordium initiation, supporting a role in specification of floral organ
      identity.
    action: ACCEPT
    reason: >-
      This is a core AP2 developmental process annotation supported by
      loss-of-function floral-organ identity phenotypes.
    supported_by:
    - reference_id: PMID:2535466
      supporting_text: "Temperature shift experiments indicate that the wild-type AP2 gene product acts at the time of primordium initiation"
    - reference_id: PMID:2535466
      supporting_text: "cells to determine their place in the developing flower and thus to differentiate appropriately"
- term:
    id: GO:0048481
    label: plant ovule development
  evidence_type: IGI
  original_reference_id: PMID:22914576
  review:
    summary: >-
      The BR/BZR1 paper supports a genetic relationship between AP2 and ovule
      number/developmental gene expression, and independent AP2 seed papers also
      describe roles in ovule and seed-coat development. However, this annotation
      is a specific reproductive-development output rather than AP2's core
      molecular function, and the original cached paper is abstract-only.
    action: KEEP_AS_NON_CORE
    reason: >-
      Keep as a supported non-core process. The evidence is consistent with AP2
      influencing ovule development, but the main AP2 function remains nuclear
      transcriptional regulation of floral, meristem, and seed developmental
      programs.
    supported_by:
    - reference_id: PMID:22914576
      supporting_text: "the expression level of genes related to ovule development, including HLL, ANT,"
    - reference_id: PMID:22914576
      supporting_text: "BZR1 and AP2 probably affect Arabidopsis ovule number determination"
    - reference_id: PMID:15708976
      supporting_text: "development of the ovule and seed coat"
- term:
    id: GO:0010073
    label: meristem maintenance
  evidence_type: IMP
  original_reference_id: PMID:16387832
  review:
    summary: >-
      AP2 was implicated in shoot meristem stem-cell niche maintenance through a
      dominant-negative allele that disrupts WUS and CLV3 expression and modifies
      the WUS-CLV3 feedback loop.
    action: ACCEPT
    reason: >-
      The IMP annotation is supported by AP2 mutant phenotypes and molecular
      markers of the shoot meristem stem-cell niche. This process is part of the
      AP2 developmental regulatory program.
    supported_by:
    - reference_id: PMID:16387832
      supporting_text: "Expression of both WUSCHEL ( WUS ) and CLAVATA3 ( CLV3 ) genes, which regulate stem cell maintenance in the wild type, were disrupted"
    - reference_id: PMID:16387832
      supporting_text: "AP2 functions in stem cell maintenance by modifying the WUS - CLV3 feedback loop"
- term:
    id: GO:0010093
    label: specification of floral organ identity
  evidence_type: IMP
  original_reference_id: PMID:12359889
  review:
    summary: >-
      Three AP2 mutant alleles displayed homeotic perianth transformations,
      directly supporting AP2's role in specifying floral organ identity.
    action: ACCEPT
    reason: >-
      This is one of the central AP2 functions and is supported by direct mutant
      phenotype analysis of perianth organ identity.
    supported_by:
    - reference_id: PMID:12359889
      supporting_text: "AP2 gene is required early in floral development to direct primordia of the first and second whorls to develop as perianth rather than as reproductive organs"
- term:
    id: GO:0048316
    label: seed development
  evidence_type: IMP
  original_reference_id: PMID:15708974
  review:
    summary: >-
      Genetic analyses showed that AP2 affects seed size, seed weight, seed oil
      and protein accumulation, seed yield, and maternal/endosperm contributions
      to seed traits.
    action: ACCEPT
    reason: >-
      The seed-development annotation is well supported by direct ap2 mutant and
      transgenic evidence. The term is broad but appropriate because AP2 affects
      several aspects of seed development rather than a single isolated seed
      phenotype.
    supported_by:
    - reference_id: PMID:15708974
      supporting_text: "AP2 also plays an important role in determining seed size, seed weight, and the accumulation of seed oil and protein."
    - reference_id: PMID:15708974
      supporting_text: "AP2 acts through the maternal sporophyte and endosperm genomes to control seed weight and seed yield."
- term:
    id: GO:0048316
    label: seed development
  evidence_type: IMP
  original_reference_id: PMID:15708976
  review:
    summary: >-
      Independent genetic analysis showed that loss-of-function ap2 mutations
      increase seed mass and that AP2 acts maternally, affecting embryo cell
      number, embryo cell size, and soluble sugar dynamics during seed
      development.
    action: ACCEPT
    reason: >-
      The annotation is supported by direct loss-of-function and reciprocal-cross
      evidence for AP2 control of seed development and seed mass.
    supported_by:
    - reference_id: PMID:15708976
      supporting_text: "Reciprocal cross experiments showed that AP2 acts maternally to control seed mass."
    - reference_id: PMID:15708976
      supporting_text: "The maternal effect of AP2 on seed mass involves the regulation of both embryo cell number and cell size."
- term:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  evidence_type: TAS
  original_reference_id: PMID:7919989
  review:
    summary: >-
      The AP2 cloning paper identified AP2 as a putative nuclear regulatory
      protein with AP2 domains and connected this protein to floral and seed
      developmental regulation.
    action: ACCEPT
    reason: >-
      DNA-binding transcription factor activity is the best supported core
      molecular function for AP2.
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "AP2 represents a new class of plant regulatory proteins"
    - reference_id: PMID:7919989
      supporting_text: "the AP2 domain"
- term:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  evidence_type: ISS
  original_reference_id: PMID:11118137
  review:
    summary: >-
      The ISS annotation is based on Arabidopsis transcription-factor family
      analysis. Although the cached paper is abstract-only and not AP2-specific
      in its abstract, the conclusion is consistent with AP2 family/domain and
      AP2-specific experimental evidence.
    action: ACCEPT
    reason: >-
      Retain because AP2 is a well-established AP2/ERF DNA-binding transcription
      factor. The original source is broad comparative evidence, so stronger
      AP2-specific sources should be preferred for curation narratives.
    supported_by:
    - reference_id: PMID:11118137
      supporting_text: "Arabidopsis dedicates over 5% of its genome to code for more than 1500"
    - reference_id: file:interpro/panther/PTHR32467/PTHR32467-entries.csv
      supporting_text: "P47927,Floral homeotic protein APETALA 2,protein,3702,Arabidopsis thaliana,Arabidopsis thaliana (Mouse-ear cress),AP2,432,PTHR32467:SF142,FLORAL HOMEOTIC PROTEIN APETALA 2,True"
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: TAS
  original_reference_id: PMID:7919989
  review:
    summary: >-
      The original AP2 paper describes AP2 as a putative nuclear protein and
      identified the AP2 domain. This supports the nuclear annotation, though it
      is not a modern direct fluorescent-localization assay.
    action: ACCEPT
    reason: >-
      Nucleus is consistent with AP2's predicted nuclear protein sequence,
      nuclear localization signal, and DNA-binding transcription-factor
      function.
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "it encodes a putative nuclear protein"
    - reference_id: file:ARATH/AP2/AP2-uniprot.txt
      supporting_text: "SUBCELLULAR LOCATION: Nucleus"
- term:
    id: GO:0006355
    label: regulation of DNA-templated transcription
  evidence_type: TAS
  original_reference_id: PMID:7919989
  review:
    summary: >-
      AP2 was described as regulating floral homeotic gene expression, and later
      direct-target studies establish AP2 as a transcriptional activator and
      repressor.
    action: ACCEPT
    reason: >-
      The term accurately reflects AP2's central biological role in
      transcriptional regulation.
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "the regulation of floral homeotic gene expression in Arabidopsis"
    - reference_id: file:ARATH/AP2/AP2-deep-research-falcon.md
      supporting_text: "AP2 directly binds the SOC1 promoter and represses SOC1 transcription during vegetative development"
- term:
    id: GO:0030154
    label: cell differentiation
  evidence_type: TAS
  original_reference_id: PMID:7919989
  review:
    summary: >-
      The original AP2 literature supports developmental cell fate and organ
      identity effects, but GO:0030154 is too generic for AP2 and obscures the
      specific floral homeotic process.
    action: MODIFY
    reason: >-
      Replace broad cell differentiation with AP2's specific, directly supported
      floral development and floral organ identity specification terms.
    proposed_replacement_terms:
    - id: GO:0010093
      label: specification of floral organ identity
    - id: GO:0009908
      label: flower development
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "APETALA2 (AP2) plays a central role in the establishment of the floral meristem, the specification of floral organ identity, and the regulation of floral homeotic gene expression in Arabidopsis."
    - reference_id: PMID:2535466
      supporting_text: "cells to determine their place in the developing flower and thus to differentiate appropriately"
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: ISS
  original_reference_id: PMID:7919989
  review:
    summary: >-
      The ISS nuclear annotation is consistent with the AP2 paper's putative
      nuclear protein description, UniProt's NLS and nuclear localization
      annotation, and AP2's DNA-binding transcription-factor function.
    action: ACCEPT
    reason: >-
      Nucleus is the appropriate location for AP2 activity.
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "putative nuclear protein"
    - reference_id: file:ARATH/AP2/AP2-uniprot.txt
      supporting_text: "Nuclear localization signal"
- term:
    id: GO:0009908
    label: flower development
  evidence_type: TAS
  original_reference_id: PMID:7919989
  review:
    summary: >-
      AP2 is a floral homeotic regulator required for floral meristem identity,
      perianth organ identity, and normal flower development.
    action: ACCEPT
    reason: >-
      Flower development is a broad but accurate AP2 biological-process
      annotation, supported by direct mutant and expression evidence.
    supported_by:
    - reference_id: PMID:7919989
      supporting_text: "in addition to its functions during flower development, AP2 activity is also required during seed development"
    - reference_id: PMID:12359889
      supporting_text: "AP2 gene is required early in floral development"
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO terms
  findings:
  - statement: >-
      InterPro domain-to-GO mappings correctly recognize AP2/ERF DNA-binding and
      transcription-factor function, but the generic DNA binding term is less
      informative than AP2's transcription-factor activity.
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings:
  - statement: >-
      IBA annotations from PANTHER support conserved AP2/ERF transcriptional
      regulation; the transcription regulator complex term is retained only as
      non-core context.
- id: GO_REF:0000044
  title: >-
    Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location
    vocabulary mapping, accompanied by conservative changes to GO terms applied
    by UniProt
  findings:
  - statement: UniProt maps AP2 to the nuclear cellular component.
- id: GO_REF:0000117
  title: Electronic Gene Ontology annotations created by ARBA machine learning models
  findings:
  - statement: >-
      ARBA recovers AP2 DNA-binding capacity but uses a generic DNA binding term
      that should be replaced by transcription-factor-specific terms.
- id: GO_REF:0000122
  title: AtSubP analysis
  findings:
  - statement: AtSubP predicts nuclear localization, consistent with AP2 function.
- id: PMID:11118137
  title: 'Arabidopsis transcription factors: genome-wide comparative analysis among eukaryotes.'
  full_text_unavailable: true
  findings:
  - statement: >-
      Broad Arabidopsis transcription-factor family analysis supports AP2 as a
      plant-family transcription factor, but the cached abstract is not
      AP2-specific.
- id: PMID:12359889
  title: AP2 Gene Determines the Identity of Perianth Organs in Flowers of Arabidopsis thaliana.
  full_text_unavailable: true
  findings:
  - statement: >-
      AP2 mutant alleles transform sepals and petals, supporting AP2's role in
      perianth/floral organ identity specification.
- id: PMID:15708974
  title: Control of seed mass and seed yield by the floral homeotic gene APETALA2.
  findings:
  - statement: >-
      AP2 controls seed size, seed weight, seed oil/protein accumulation, and
      seed yield through maternal sporophyte and endosperm contributions.
- id: PMID:15708976
  title: Control of seed mass by APETALA2.
  findings:
  - statement: >-
      AP2 loss-of-function alleles increase seed mass; reciprocal crosses show a
      maternal effect involving embryo cell number and cell size.
- id: PMID:16387832
  title: APETALA2 regulates the stem cell niche in the Arabidopsis shoot meristem.
  findings:
  - statement: >-
      AP2 affects shoot meristem stem-cell niche maintenance through disruption
      of WUS/CLV3 expression and the WUS-CLV3 feedback loop.
- id: PMID:22914576
  title: BR signal influences Arabidopsis ovule and seed number through regulating related genes expression by BZR1.
  full_text_unavailable: true
  findings:
  - statement: >-
      The abstract supports AP2 involvement in BR/BZR1-related ovule number
      determination, but the full text is not cached.
- id: PMID:2535466
  title: Genes directing flower development in Arabidopsis.
  full_text_unavailable: true
  findings:
  - statement: >-
      apetala2-1 flower phenotypes and temperature-shift experiments support AP2
      action during early floral primordium identity determination.
- id: PMID:25533953
  title: An Arabidopsis gene regulatory network for secondary cell wall synthesis.
  findings:
  - statement: >-
      Yeast one-hybrid network screening provides high-throughput
      transcription-factor promoter-binding context; the AP2-specific
      supplementary interaction is not visible in the cached main text.
- id: PMID:30356219
  title: Transcriptional regulation of nitrogen-associated metabolism and growth.
  full_text_unavailable: true
  findings:
  - statement: >-
      The cached record is abstract-only and does not expose the AP2-specific
      promoter-binding result behind the GOA annotation.
- id: PMID:7919989
  title: Control of Arabidopsis flower and seed development by the homeotic gene APETALA2.
  full_text_unavailable: true
  findings:
  - statement: >-
      The AP2 cloning paper supports AP2 as a putative nuclear AP2-domain
      regulatory protein required for floral meristem, floral organ, and seed
      development.
- id: file:ARATH/AP2/AP2-uniprot.txt
  title: UniProtKB record for Arabidopsis APETALA2 (P47927)
  findings:
  - statement: >-
      UniProt describes AP2 as a nuclear AP2/ERF transcription factor with two
      DNA-binding domains, a nuclear localization signal, and an EAR motif.
- id: file:ARATH/AP2/AP2-deep-research-falcon.md
  title: Falcon deep research report for Arabidopsis AP2
  findings:
  - statement: >-
      Deep research integrates AP2-specific literature on direct genomic
      binding, target activation/repression, miR172 regulation, SAM morphology,
      TOPLESS/HDA19 repression, and seed coat proanthocyanidin regulation.
- id: file:interpro/panther/PTHR32467/PTHR32467-entries.csv
  title: PANTHER PTHR32467 AP2-like ethylene-responsive transcription factor family entries
  findings:
  - statement: >-
      PANTHER places Arabidopsis AP2 in PTHR32467:SF142, floral homeotic protein
      APETALA 2, alongside rice APETALA2-like proteins.
core_functions:
- description: >-
    Nuclear AP2/ERF DNA-binding transcription factor activity that binds
    transcriptional cis-regulatory regions and regulates developmental gene
    expression. The broader GO:0003700 molecular-function term is retained here
    deliberately because the current AP2 GOA supports AP2/ERF DNA-binding
    transcription factor activity but does not yet include a curated
    RNA-polymerase-II-specific GO:0000981 annotation. AP2 acts as a
    context-dependent transcriptional activator and repressor, including
    repression through TOPLESS/HDA19-associated mechanisms, to control floral
    meristem and floral organ identity, shoot meristem maintenance/transition
    morphology, and seed developmental programs.
  molecular_function:
    id: GO:0003700
    label: DNA-binding transcription factor activity
  directly_involved_in:
  - id: GO:0006355
    label: regulation of DNA-templated transcription
  - id: GO:0010093
    label: specification of floral organ identity
  - id: GO:0010073
    label: meristem maintenance
  - id: GO:0048316
    label: seed development
  - id: GO:0009908
    label: flower development
  locations:
  - id: GO:0005634
    label: nucleus
  supported_by:
  - reference_id: PMID:7919989
    supporting_text: "APETALA2 (AP2) plays a central role in the establishment of the floral meristem, the specification of floral organ identity, and the regulation of floral homeotic gene expression in Arabidopsis."
  - reference_id: PMID:16387832
    supporting_text: "AP2 functions in stem cell maintenance by modifying the WUS - CLV3 feedback loop"
  - reference_id: PMID:15708974
    supporting_text: "AP2 also plays an important role in determining seed size, seed weight, and the accumulation of seed oil and protein."
  - reference_id: file:ARATH/AP2/AP2-deep-research-falcon.md
    supporting_text: "AP2 is best annotated as a sequence-specific transcription factor with context-dependent activator/repressor roles."
proposed_new_terms: []
suggested_questions:
- question: >-
    Which AP2 direct target genes mediate seed mass and seed-coat metabolic
    phenotypes, and which effects are indirect consequences of altered floral or
    ovule development?
- question: >-
    What cofactors determine whether AP2 acts as a transcriptional activator or
    as a TOPLESS/HDA19-associated repressor at a given target locus?
- question: >-
    Are the AP2 cis-regulatory binding annotations from secondary cell wall and
    nitrogen-response network studies reproducible in AP2-expressing tissues?
- question: >-
    Which AP2-containing transcriptional assemblies are stable or direct enough
    to justify a more specific complex annotation than generic transcription
    regulator complex?
suggested_experiments:
- description: >-
    Perform native-promoter AP2 CUT&RUN or ChIP-seq in floral meristems, shoot
    apices during floral transition, seed coat, and endosperm, paired with acute
    AP2 perturbation RNA-seq, to separate direct AP2 targets from downstream
    developmental effects.
  experiment_type: genomics
- description: >-
    Use AP2 affinity purification followed by mass spectrometry in flower and
    seed tissues to identify tissue-specific AP2 cofactors, including
    TOPLESS/HDA19 and MYBL2/MBW-related complexes.
  experiment_type: proteomics
- description: >-
    Edit AP2-bound cis-regulatory motifs at priority targets such as SOC1, AG,
    and MYBL2 and assay target expression plus meristem, floral organ, and seed
    phenotypes.
  experiment_type: genome editing
- description: >-
    Validate the AP2 high-throughput cis-regulatory binding calls from the
    secondary wall and nitrogen network studies using targeted EMSA, Y1H
    retesting, or ChIP-qPCR in relevant tissues.
  experiment_type: DNA binding assay