FVE (MSI4/ACG1) is a histone-binding MSI1-like WD40 protein that participates in nuclear chromatin regulatory assemblies. It associates with histone deacetylase machinery, CUL4-DDB1 and CLF/PRC2-associated factors, supporting repression of FLOWERING LOCUS C (FLC) and flowering-time regulation. Its molecular role is noncatalytic histone/complex association; the partner enzymes carry out deacetylation and methylation. FVE also contributes to regulation of FT, cold-responsive genes, RNA-directed DNA methylation at a subset of loci, UV-B damage responses and systemic acquired resistance. These functions need not all operate through the same assembly or through FLC.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000118 histone deacetylase complex | IDA PMID:34144927 Arabidopsis RPD3-like histone deacetylases form multiple com... | ACCEPT | Summary: FVE co-purifies with HDA6/HDA19-containing plant histone deacetylase complexes. Reason: Consistent with independent evidence that FVE forms a deacetylase complex with HDA5, HDA6 and FLD and is required for histone deacetylation at FLC. Core complex membership. Supporting Evidence: PMID:34144927 Here, we perform affinity purification followed by mass spectrometry and demonstrate that the Arabidopsis RPD3-type histone deacetylases HDA6 and HDA19 interact with several previously uncharacterized proteins, thereby forming three types of plant-specific histone deacetylase complexes, which we named SANT, ESANT, and ARID. PMID:14745447 We conclude that FVE participates in a protein complex repressing FLC transcription through a histone deacetylation mechanism. |
| GO:0005515 protein binding | IPI PMID:21282611 MSI4/FVE interacts with CUL4-DDB1 and a PRC2-like complex to... | REMOVE | Summary: Interaction with CLF (PRC2 methyltransferase). Reason: Uninformative 'protein binding'; removal does not dispute the interaction. FVE membership in CLF-PRC2 is captured by the ESC/E(Z) complex (GO:0035098) annotation. Supporting Evidence: PMID:21282611 Here we report that the MSI4 protein is a DDB1 and CUL4-associated factor that represses FLC expression through its association with a CLF-Polycomb Repressive Complex 2 (PRC2) in Arabidopsis. |
| GO:0005515 protein binding | IPI PMID:21282611 MSI4/FVE interacts with CUL4-DDB1 and a PRC2-like complex to... | REMOVE | Summary: Interaction with DDB1A. Reason: Uninformative; the CUL4-DDB1 association is captured by GO:0080008. Supporting Evidence: PMID:21282611 Here we report that the MSI4 protein is a DDB1 and CUL4-associated factor that represses FLC expression through its association with a CLF-Polycomb Repressive Complex 2 (PRC2) in Arabidopsis. |
| GO:0005515 protein binding | IPI PMID:22960247 The E3 ubiquitin ligase HOS1 regulates low ambient temperatu... | REMOVE | Summary: Interaction with the E3 ligase HOS1 (Y2H, co-IP). Reason: Uninformative 'protein binding'; removal does not dispute the interaction. Supporting Evidence: PMID:22960247 HOS1 physically interacted with FVE and FLK in yeast two-hybrid and co-immunoprecipitation assays. |
| GO:0005515 protein binding | IPI PMID:23394836 A matrix protein silences transposons and repeats through in... | REMOVE | Summary: Interaction with the AT-hook nuclear matrix protein TEK. Reason: Uninformative 'protein binding'; removal does not dispute the interaction. Supporting Evidence: PMID:23394836 TEK directly binds to an FLC-repressive regulatory region and the silencing repeats of FWA and associates with Arabidopsis homologs of the Retinoblastoma-associated protein 46/48, FVE and MSI5, which mediate histone deacetylation. |
| GO:0005515 protein binding | IPI PMID:25600937 Arabidopsis thaliana MSI4/FVE associates with members of a n... | REMOVE | Summary: Co-immunopurification of MSI4 with RRM/PWWP-domain proteins. Reason: Uninformative 'protein binding'; removal does not dispute the associations. Supporting Evidence: PMID:25600937 Many of the proteins associated with AtMSI4 have distinct RNA recognition motif (RRM) domains, which we determined to be responsible for association with AtMSI4; and most of the associated RRM domain proteins also contain PWWP domains that are specific to plants. |
| GO:0005515 protein binding | IPI PMID:29314758 Arabidopsis PWWP domain proteins mediate H3K27 trimethylatio... | REMOVE | Summary: Interaction with PWWP-domain proteins (PDPs). Reason: Uninformative 'protein binding'; the PRC2-associated role is captured by GO:0035098. Supporting Evidence: PMID:29314758 Here, we report that the PWWP domain proteins (PDPs) interact with FVE and MSI5 to suppress FLC expression and thereby promote flowering. |
| GO:0005515 protein binding | IPI PMID:29314758 Arabidopsis PWWP domain proteins mediate H3K27 trimethylatio... | REMOVE | Summary: Interaction with PWWP-domain proteins (PDPs). Reason: Uninformative 'protein binding'. Supporting Evidence: PMID:29314758 Here, we report that the PWWP domain proteins (PDPs) interact with FVE and MSI5 to suppress FLC expression and thereby promote flowering. |
| GO:0005515 protein binding | IPI PMID:29314758 Arabidopsis PWWP domain proteins mediate H3K27 trimethylatio... | REMOVE | Summary: Interaction from the PDP/LHP1 study. Reason: Uninformative 'protein binding'. Supporting Evidence: PMID:29314758 We demonstrated that FVE, MSI5, and PDP3 were co-purified with LHP1. |
| GO:0005515 protein binding | IPI PMID:29314758 Arabidopsis PWWP domain proteins mediate H3K27 trimethylatio... | REMOVE | Summary: Interaction from the PDP/LHP1 study. Reason: Uninformative 'protein binding'. Supporting Evidence: PMID:29314758 We demonstrated that FVE, MSI5, and PDP3 were co-purified with LHP1. |
| GO:0005515 protein binding | IPI PMID:29314758 Arabidopsis PWWP domain proteins mediate H3K27 trimethylatio... | REMOVE | Summary: Interaction from the PDP/LHP1 study. Reason: Uninformative 'protein binding'. Supporting Evidence: PMID:29314758 We demonstrated that FVE, MSI5, and PDP3 were co-purified with LHP1. |
| GO:0005515 protein binding | IPI PMID:29314758 Arabidopsis PWWP domain proteins mediate H3K27 trimethylatio... | REMOVE | Summary: Interaction from the PDP/LHP1 study. Reason: Uninformative 'protein binding'. Supporting Evidence: PMID:29314758 We demonstrated that FVE, MSI5, and PDP3 were co-purified with LHP1. |
| GO:0005515 protein binding | IPI PMID:33942410 FVE promotes RNA-directed DNA methylation by facilitating th... | REMOVE | Summary: Interaction with SUVH9 linking FVE to Pol V association in RdDM. Reason: Uninformative 'protein binding'; removal does not dispute the interaction. Supporting Evidence: PMID:33942410 Here we found that SUVH9 interacts with FVE, a homolog of the mammalian retinoblastoma-associated protein, which has been previously identified as a shared subunit of the histone deacetylase complex and the polycomb-type histone H3K27 trimethyltransferase complex. |
| GO:0005634 nucleus | HDA PMID:15610358 High-throughput protein localization in Arabidopsis using Ag... | ACCEPT | Summary: Nuclear GFP localization in a high-throughput screen. Reason: Consistent with targeted localization studies. Supporting Evidence: PMID:22960247 A HOS1-green fluorescent protein (GFP) fusion co-localized with FVE-GFP in the nucleus at both 16 and 23°C. |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: Nucleus propagated by PAINT within the MSI1-like family. Reason: Consistent with experimental data. Supporting Evidence: PMID:22960247 A HOS1-green fluorescent protein (GFP) fusion co-localized with FVE-GFP in the nucleus at both 16 and 23°C. |
| GO:0005634 nucleus | IDA PMID:22960247 The E3 ubiquitin ligase HOS1 regulates low ambient temperatu... | ACCEPT | Summary: FVE-GFP is nuclear. Reason: Direct experimental evidence. Supporting Evidence: PMID:22960247 A HOS1-green fluorescent protein (GFP) fusion co-localized with FVE-GFP in the nucleus at both 16 and 23°C. |
| GO:0005634 nucleus | IEA GO_REF:0000044 | ACCEPT | Summary: Nucleus from UniProt subcellular location mapping. Reason: Consistent with experimental data. Supporting Evidence: PMID:22960247 A HOS1-green fluorescent protein (GFP) fusion co-localized with FVE-GFP in the nucleus at both 16 and 23°C. |
| GO:0005634 nucleus | ISM GO_REF:0000122 | ACCEPT | Summary: Nucleus predicted by AtSubP. Reason: Consistent with experimental data. Supporting Evidence: PMID:22960247 A HOS1-green fluorescent protein (GFP) fusion co-localized with FVE-GFP in the nucleus at both 16 and 23°C. |
| GO:0005730 nucleolus | HDA PMID:15496452 Proteomic analysis of the Arabidopsis nucleolus suggests nov... | KEEP AS NON CORE | Summary: The nucleolar observation is corroborated by the original localization database figure. Reason: The original PMID:15496452 nucleolar proteomics assertion is independently corroborated by the target row in AtNoPDB PMID:15608277 Figure 1: AT2G19520/MSI4 is coded NU:no:NAS, meaning strong nucleoplasmic, weaker nucleolar and nucleolus-associated-structure labeling. This supports the compartment without assigning a specific nucleolar function. The row was recovered from the publisher PDF text extraction; the original supplementary table was not recovered. Supporting Evidence: file:ARATH/FVE/FVE-source-analysis/README.md At2g19520 | WD-40 repeat protein (MSI4) | DNA interacting protein | NU:no:NAS |
| GO:0005737 cytoplasm | HDA PMID:15610358 High-throughput protein localization in Arabidopsis using Ag... | UNDECIDED | Summary: The specific cytoplasmic target observation remains unresolved. Reason: The curator-made HDA cytoplasm assertion is preserved as a source claim. PMID:15610358 is available only as an abstract here, and the exact FVE GFP-localization image or target table was not recovered. Independent nuclear localization neither excludes nor establishes a cytoplasmic pool. Retain UNDECIDED because this specific observation cannot be independently assessed, without alleging a mistaken target assignment or treating missing access as negative localization evidence. |
| GO:0005739 mitochondrion | HDA PMID:28887381 Global Analysis of Membrane-associated Protein Oligomerizati... | MARK AS OVER ANNOTATED | Summary: The mixed-microsome dataset does not establish the specific mitochondrial assignment. Reason: The actual deposited target rows were inspected across all seven XLSX supplements. Table S1 Mapp row432 identifies AT2G19520/FVE and classifies it as nucleus, with empty True membrane and Dual Localized fields; the sucrose raw-protein table independently lists nucleus. The experiment uses mixed microsomal fractions, so target detection is real but mitochondrial residence is more specific than this source supports. This judgment does not rest on absence of a targeting signal or on nuclear localization excluding a second pool. Supporting Evidence: file:ARATH/FVE/FVE-source-analysis/README.md The Subacon localization field is nucleus. The True membrane and Dual Localized fields are empty. |
| GO:0005829 cytosol | HDA PMID:25293756 A proteomic strategy for global analysis of plant protein co... | UNDECIDED | Summary: The specific cytosolic target observation remains unresolved. Reason: The curator-made HDA cytosol assertion is preserved as a source claim. The inspected PMID:25293756 main text does not identify FVE, and the attempt to retrieve the target-level supplementary data returned a non-ZIP response, documented in the source-analysis artifacts. This leaves the specific fractionation assignment unresolved; it does not demonstrate misattribution or absence from cytosol. The separate cytoplasm annotation and known nuclear role cannot independently adjudicate this particular experiment. |
| GO:0006281 DNA repair | IMP PMID:22170978 Participation of chromatin-remodeling proteins in the repair... | KEEP AS NON CORE | Summary: Plants deficient in NFC4 (MSI4/FVE) accumulate more UV-B-induced DNA damage. Reason: Genetic requirement for efficient repair of UV-B damage, probably via chromatin accessibility; non-core. Supporting Evidence: PMID:22170978 Plants deficient in NFC102/NFC4 or SDG102/SDG26 showed more damaged DNA than wild-type plants |
| GO:0006338 chromatin remodeling | IBA GO_REF:0000033 | ACCEPT | Summary: Chromatin remodeling propagated within the MSI1/RbAp48 family. Reason: FVE is a histone-binding subunit of chromatin-modifying complexes (HDAC, PRC2). Supporting Evidence: PMID:9872415 The mammalian RbAp48 protein is the most extensively studied member of the conserved family of Msi1-like WD-40 repeat proteins, which are components of complexes involved in the assembly and modification of chromatin. |
| GO:0006355 regulation of DNA-templated transcription | IBA GO_REF:0000033 | ACCEPT | Summary: Regulation of transcription propagated within the MSI1-like family. Reason: FVE-containing complexes repress transcription of FLC and other targets. Supporting Evidence: PMID:14745447 We conclude that FVE participates in a protein complex repressing FLC transcription through a histone deacetylation mechanism. |
| GO:0006355 regulation of DNA-templated transcription | IEA GO_REF:0000117 | ACCEPT | Summary: Regulation of transcription from ARBA. Reason: Consistent with experimental evidence. Supporting Evidence: PMID:14745447 We conclude that FVE participates in a protein complex repressing FLC transcription through a histone deacetylation mechanism. |
| GO:0006355 regulation of DNA-templated transcription | IMP PMID:29314758 Arabidopsis PWWP domain proteins mediate H3K27 trimethylatio... | ACCEPT | Summary: FVE with PDPs suppresses FLC expression (IMP). Reason: Experimental support. Supporting Evidence: PMID:29314758 This study suggests that PDPs function together with FVE and MSI5 to regulate the function of the PRC2 complex on FLC. |
| GO:0009627 systemic acquired resistance | IMP PMID:32392578 Dehydroabietinal promotes flowering time and plant defense i... | KEEP AS NON CORE | Summary: fve mutants are defective in systemic acquired resistance. Reason: Pleiotropic role; the SAR arm is FLC-independent and its mechanism is unknown. Supporting Evidence: PMID:32392578 We suggest that SAR and flowering time signaling pathways bifurcate at a step downstream of FLD, REF6, and FVE, with an FLC-dependent arm controlling flowering time, and an FLC-independent pathway controlling SAR. |
| GO:0010224 response to UV-B | IEP PMID:22170978 Participation of chromatin-remodeling proteins in the repair... | KEEP AS NON CORE | Summary: Expression/response to UV-B (IEP). Reason: Response annotation, not a core function. IEP asserts an expression change in response to UV-B; the cached abstract (full text not cached) reports only the mutant DNA-damage phenotype, not FVE/NFC4 expression changes, so no supporting sentence is cited and we defer to the curator's reading of the full text. |
| GO:0010629 negative regulation of gene expression | IEA GO_REF:0000117 | ACCEPT | Summary: Negative regulation of gene expression from ARBA. Reason: FVE represses FLC and cold-responsive genes. Supporting Evidence: PMID:21282611 Thus, the lack of MSI4 or decreased CUL4 activity reduces H3K27 trimethylation on FLC, but also on its downstream target FT, resulting in increased expression of both genes. |
| GO:0035098 ESC/E(Z) complex | IDA PMID:29314758 Arabidopsis PWWP domain proteins mediate H3K27 trimethylatio... | ACCEPT | Summary: FVE co-purifies with LHP1/PRC2 components and is required for H3K27me3 at FLC. Reason: Retain the curated PRC2-associated complex assignment, supported by FVE association with CLF and LHP1/PDP-containing machinery and FVE-dependent H3K27me3. PMID:21282611 and PMID:29314758 do not establish FVE as an invariant stoichiometric core of every Arabidopsis PRC2 complex; membership is interpreted in the reported FLC-associated context, not solely from animal RbAp homology. Supporting Evidence: PMID:29314758 We demonstrated that FVE, MSI5, and PDP3 were co-purified with LHP1. PMID:21282611 Here we report that the MSI4 protein is a DDB1 and CUL4-associated factor that represses FLC expression through its association with a CLF-Polycomb Repressive Complex 2 (PRC2) in Arabidopsis. |
| GO:0035098 ESC/E(Z) complex | IEA GO_REF:0000117 | ACCEPT | Summary: ESC/E(Z) complex from ARBA. Reason: Retain the curated PRC2-associated complex assignment, supported by FVE association with CLF and LHP1/PDP-containing machinery and FVE-dependent H3K27me3. PMID:21282611 and PMID:29314758 do not establish FVE as an invariant stoichiometric core of every Arabidopsis PRC2 complex; membership is interpreted in the reported FLC-associated context, not solely from animal RbAp homology. Supporting Evidence: PMID:21282611 Here we report that the MSI4 protein is a DDB1 and CUL4-associated factor that represses FLC expression through its association with a CLF-Polycomb Repressive Complex 2 (PRC2) in Arabidopsis. |
| GO:0040029 epigenetic regulation of gene expression | IEA GO_REF:0000117 | MODIFY | Summary: FVE supports repressive chromatin regulation. Reason: FVE-containing chromatin assemblies repress FLC and other target genes through histone deacetylation and PRC2-associated H3K27 methylation. The more precise directional process GO:0045814 is supported independently of the electronic source and is applied consistently to both rows for the same broad process. Proposed replacements: negative regulation of gene expression, epigenetic Supporting Evidence: PMID:21282611 Thus, the lack of MSI4 or decreased CUL4 activity reduces H3K27 trimethylation on FLC, but also on its downstream target FT, resulting in increased expression of both genes. |
| GO:0040029 epigenetic regulation of gene expression | IMP PMID:29314758 Arabidopsis PWWP domain proteins mediate H3K27 trimethylatio... | MODIFY | Summary: FVE supports repressive chromatin regulation. Reason: FVE-containing chromatin assemblies repress FLC and other target genes through histone deacetylation and PRC2-associated H3K27 methylation. The more precise directional process GO:0045814 is supported independently of the electronic source and is applied consistently to both rows for the same broad process. Proposed replacements: negative regulation of gene expression, epigenetic Supporting Evidence: PMID:29314758 The H3K27me3 level on FLC was decreased in the pdp mutants as well as in the fve/msi5 double mutant. PMID:14745447 We conclude that FVE participates in a protein complex repressing FLC transcription through a histone deacetylation mechanism. |
| GO:0042393 histone binding | IBA GO_REF:0000033 | ACCEPT | Summary: Histone binding propagated from p55/RbAp48/Hat2 family members. Reason: Core molecular activity of MSI1-like WD40 proteins, which bind histone H3/H4 to target chromatin-modifying complexes; FVE is a clear member of this conserved family. Supporting Evidence: PMID:9872415 The mammalian RbAp48 protein is the most extensively studied member of the conserved family of Msi1-like WD-40 repeat proteins, which are components of complexes involved in the assembly and modification of chromatin. |
| GO:0046872 metal ion binding | IDA PMID:9872415 AtMSI4 and RbAp48 WD-40 repeat proteins bind metal ions. | MODIFY | Summary: Recombinant AtMSI4 binds 3-4 metal ions per molecule, preferring zinc. Reason: The in vitro data indicate a preference for zinc; zinc ion binding is more specific. The physiological relevance of metal binding is unclear, so this is not a core function. Proposed replacements: zinc ion binding Supporting Evidence: PMID:9872415 Metal competition assays indicate a preference for zinc. |
| GO:0048510 regulation of timing of transition from vegetative to reproductive phase | IMP PMID:25922987 Regulation of flowering time by the histone deacetylase HDA5... | ACCEPT | Summary: FVE forms an HDA5/HDA6/FLD complex regulating flowering time. Reason: Well-established role in promoting flowering via FLC repression. Supporting Evidence: PMID:25922987 Bimolecular fluorescence complementation assays and co-immunoprecipitation assays showed that HDA5 interacts with FVE, FLD and HDA6, indicating that these proteins are present in a protein complex involved in the regulation of flowering time. |
| GO:0080008 Cul4-RING E3 ubiquitin ligase complex | ISS PMID:18223036 Characterization of Arabidopsis and rice DWD proteins and th... | ACCEPT | Summary: Cul4-RING ligase complex by similarity as a DWD protein; experimentally MSI4 is a DDB1-CUL4-associated factor. Reason: Supported by later experimental evidence that MSI4 associates with CUL4-DDB1 and that this is needed for FLC repression. Supporting Evidence: PMID:21282611 Moreover, CUL4 interacts with FLC chromatin in an MSI4-dependant manner, and the interaction between MSI4 and CUL4-DDB1 is necessary for the epigenetic repression of FLC. |
| GO:0080188 gene silencing by siRNA-directed DNA methylation | IDA PMID:33942410 FVE promotes RNA-directed DNA methylation by facilitating th... | KEEP AS NON CORE | Summary: FVE facilitates Pol V association with chromatin and DNA methylation at a subset of RdDM loci. Reason: Experimentally supported additional role outside the flowering module. Supporting Evidence: PMID:33942410 We demonstrated that FVE facilitates the association of Pol V with chromatin and thus contributes to DNA methylation at a substantial subset of RdDM target loci. |
| GO:1904629 response to diterpene | IEP PMID:32392578 Dehydroabietinal promotes flowering time and plant defense i... | KEEP AS NON CORE | Summary: FVE expression induced by dehydroabietinal (IEP). Reason: Expression response; non-core. Supporting Evidence: PMID:32392578 DA's promotion of flowering time was mediated through up-regulation of the autonomous pathway genes FLOWERING LOCUS D (FLD), RELATIVE OF EARLY FLOWERING 6 (REF6), and FVE, which repress expression of FLOWERING LOCUS C (FLC), a negative regulator of the key floral integrator FLOWERING LOCUS T (FT). |
| GO:1904629 response to diterpene | IMP PMID:32392578 Dehydroabietinal promotes flowering time and plant defense i... | KEEP AS NON CORE | Summary: fve mutants are impaired in dehydroabietinal responses (IMP). Reason: Pleiotropic downstream response; non-core. Supporting Evidence: PMID:32392578 DA's promotion of flowering time was mediated through up-regulation of the autonomous pathway genes FLOWERING LOCUS D (FLD), RELATIVE OF EARLY FLOWERING 6 (REF6), and FVE, which repress expression of FLOWERING LOCUS C (FLC), a negative regulator of the key floral integrator FLOWERING LOCUS T (FT). |
| GO:2000028 regulation of photoperiodism, flowering | IMP PMID:32392578 Dehydroabietinal promotes flowering time and plant defense i... | UNDECIDED | Summary: The photoperiod-specific component of the DA flowering response remains unresolved. Reason: The available PMID:32392578 abstract establishes a DA-dependent flowering response through FVE and FLC, but does not resolve the daylength-dependence required to adjudicate this specific photoperiodism assertion. Autonomous-pathway membership alone is not evidence against an overlapping role in photoperiod-dependent flowering. Supporting Evidence: PMID:14745447 The vernalization and autonomous pathways converge on the negative regulation of FLC, a gene encoding a MADS-box protein that inhibits flowering. |
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Download this section (compressed HTML)Q: How is FVE partitioned between its PRC2, HDAC and CUL4-DDB1 complexes, and which of these is limiting for FLC repression versus thermosensory flowering and cold-gene repression?
Experiment: Use separation-of-function FVE variants (histone-binding pocket mutants; DDB1-binding WDxR mutants) in fve backgrounds and profile FLC H3K27me3, H3 acetylation and flowering time.
Hypothesis: Histone binding by FVE is required for both PRC2 and HDAC function at FLC, whereas DDB1 binding is specific to the CUL4-dependent arm.
Type: Genetic complementation with ChIP-qPCR
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