MYC3 (bHLH005, ATR2) is a nuclear basic helix-loop-helix transcription factor of the subgroup IIIe MYC clade that acts with its paralogs MYC2 and MYC4 as a master activator of jasmonate-responsive gene expression in Arabidopsis. MYC3 binds G-box (CACGTG) and related cis-elements with a specificity nearly identical to MYC2, forms homo- and heterodimers with MYC2 and MYC4, and recruits the Mediator subunit MED25 through its N-terminal JAZ-interaction domain (JID). In the resting state, the Jas motif of JAZ repressors binds the JID, displacing the MYC N-terminal helix and competitively blocking MED25 recruitment; JA-Ile-triggered degradation of JAZ proteins by SCF(COI1) releases MYC3. MYC3 acts additively with MYC2 and MYC4 to control defense against bacteria and insect herbivores, glucosinolate and anthocyanin production, jasmonate-mediated growth responses and stomatal development, and also represses the florigen gene FT in photoperiodic flowering.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000976 transcription cis-regulatory region binding | IBA GO_REF:0000033 | ACCEPT | Summary: Phylogenetic inference of cis-regulatory region binding, supported by protein-binding-microarray evidence that MYC3 binds G-box variants like MYC2. Reason: Consistent with direct DNA-binding data for MYC3 (PMID:21335373). Supporting Evidence: PMID:21335373 These results indicate that MYC2 and MYC3 have almost identical DNA binding specificities |
| GO:0003700 DNA-binding transcription factor activity | IBA GO_REF:0000033 | ACCEPT | Summary: MYC3 is a bHLH DNA-binding transcription factor; experimental data show sequence-specific DNA binding and transactivation. Reason: Core molecular function; inferred annotations agree with direct DNA-binding (PMID:21335373) and reporter transactivation (PMID:21321051) evidence. Supporting Evidence: PMID:21335373 They both are nuclear proteins that bind DNA with sequence specificity similar to that of MYC2. PMID:21321051 MYC2, MYC3, and MYC4 were all capable of inducing expression of JAZ::GUS reporter constructs following transfection of carrot protoplasts. |
| GO:0003700 DNA-binding transcription factor activity | IEA GO_REF:0000002 | ACCEPT | Summary: MYC3 is a bHLH DNA-binding transcription factor; experimental data show sequence-specific DNA binding and transactivation. Reason: Core molecular function; inferred annotations agree with direct DNA-binding (PMID:21335373) and reporter transactivation (PMID:21321051) evidence. Supporting Evidence: PMID:21335373 They both are nuclear proteins that bind DNA with sequence specificity similar to that of MYC2. PMID:21321051 MYC2, MYC3, and MYC4 were all capable of inducing expression of JAZ::GUS reporter constructs following transfection of carrot protoplasts. |
| GO:0003700 DNA-binding transcription factor activity | ISS PMID:11118137 Arabidopsis transcription factors: genome-wide comparative a... | ACCEPT | Summary: MYC3 is a bHLH DNA-binding transcription factor; experimental data show sequence-specific DNA binding and transactivation. Reason: Core molecular function; inferred annotations agree with direct DNA-binding (PMID:21335373) and reporter transactivation (PMID:21321051) evidence. Supporting Evidence: PMID:21335373 They both are nuclear proteins that bind DNA with sequence specificity similar to that of MYC2. PMID:21321051 MYC2, MYC3, and MYC4 were all capable of inducing expression of JAZ::GUS reporter constructs following transfection of carrot protoplasts. |
| GO:0003700 DNA-binding transcription factor activity | ISS PMID:12679534 The basic helix-loop-helix transcription factor family in pl... | ACCEPT | Summary: MYC3 is a bHLH DNA-binding transcription factor; experimental data show sequence-specific DNA binding and transactivation. Reason: Core molecular function; inferred annotations agree with direct DNA-binding (PMID:21335373) and reporter transactivation (PMID:21321051) evidence. Supporting Evidence: PMID:21335373 They both are nuclear proteins that bind DNA with sequence specificity similar to that of MYC2. PMID:21321051 MYC2, MYC3, and MYC4 were all capable of inducing expression of JAZ::GUS reporter constructs following transfection of carrot protoplasts. |
| GO:0005515 protein binding | IPI PMID:20360743 NINJA connects the co-repressor TOPLESS to jasmonate signall... | MODIFY | Summary: MYC3 binds JAZ repressors through its N-terminal JAZ-interaction domain; the Jas motif of JAZ docks into the MYC3 N-terminal fold. Reason: Generic protein binding is uninformative. The partner is a JAZ protein, which acts as a transcriptional corepressor of MYC factors; transcription corepressor binding captures the functional meaning of this interaction. Proposed replacements: transcription corepressor binding Supporting Evidence: PMID:20360743 Secondly, interaction of JAZ1 with MYC3, a close relative to MYC2, was observed. PMID:21321051 MYC3 and MYC4 interact not only with JAZ1 but also with other JAZ proteins (JAZ3 and JAZ9) in both yeast two-hybrid and pull-down assays. |
| GO:0005515 protein binding | IPI PMID:20360743 NINJA connects the co-repressor TOPLESS to jasmonate signall... | MODIFY | Summary: MYC3 binds JAZ repressors through its N-terminal JAZ-interaction domain; the Jas motif of JAZ docks into the MYC3 N-terminal fold. Reason: Generic protein binding is uninformative. The partner is a JAZ protein, which acts as a transcriptional corepressor of MYC factors; transcription corepressor binding captures the functional meaning of this interaction. Proposed replacements: transcription corepressor binding Supporting Evidence: PMID:20360743 Secondly, interaction of JAZ1 with MYC3, a close relative to MYC2, was observed. PMID:21321051 MYC3 and MYC4 interact not only with JAZ1 but also with other JAZ proteins (JAZ3 and JAZ9) in both yeast two-hybrid and pull-down assays. |
| GO:0005515 protein binding | IPI PMID:26258305 Structural basis of JAZ repression of MYC transcription fact... | MODIFY | Summary: MYC3 directly binds the Mediator subunit MED25 via its N-terminal domain; JAZ competitively blocks this interaction. Reason: Generic protein binding is uninformative. MED25 is the Mediator subunit through which MYC factors recruit the transcription machinery; transcription coactivator binding is more informative. Proposed replacements: transcription coactivator binding Supporting Evidence: PMID:26258305 We found that MYC3(44-238) also directly binds MED25 PMID:26258305 In this position, the Jas helix competitively inhibits MYC3 interaction with the MED25 subunit of the transcriptional Mediator complex. |
| GO:0005515 protein binding | IPI PMID:26258305 Structural basis of JAZ repression of MYC transcription fact... | MODIFY | Summary: MYC3 binds JAZ repressors through its N-terminal JAZ-interaction domain; the Jas motif of JAZ docks into the MYC3 N-terminal fold. Reason: Generic protein binding is uninformative. The partner is a JAZ protein, which acts as a transcriptional corepressor of MYC factors; transcription corepressor binding captures the functional meaning of this interaction. Proposed replacements: transcription corepressor binding Supporting Evidence: PMID:26258305 Here we show that Arabidopsis MYC3 undergoes pronounced conformational changes when bound to the conserved Jas motif of the JAZ9 repressor. PMID:21321051 MYC3 and MYC4 interact not only with JAZ1 but also with other JAZ proteins (JAZ3 and JAZ9) in both yeast two-hybrid and pull-down assays. |
| GO:0005515 protein binding | IPI PMID:26258305 Structural basis of JAZ repression of MYC transcription fact... | MODIFY | Summary: MYC3 binds JAZ repressors through its N-terminal JAZ-interaction domain; the Jas motif of JAZ docks into the MYC3 N-terminal fold. Reason: Generic protein binding is uninformative. The partner is a JAZ protein, which acts as a transcriptional corepressor of MYC factors; transcription corepressor binding captures the functional meaning of this interaction. Proposed replacements: transcription corepressor binding Supporting Evidence: PMID:26258305 Here we show that Arabidopsis MYC3 undergoes pronounced conformational changes when bound to the conserved Jas motif of the JAZ9 repressor. PMID:21321051 MYC3 and MYC4 interact not only with JAZ1 but also with other JAZ proteins (JAZ3 and JAZ9) in both yeast two-hybrid and pull-down assays. |
| GO:0005515 protein binding | IPI PMID:26258305 Structural basis of JAZ repression of MYC transcription fact... | MODIFY | Summary: MYC3 binds JAZ repressors through its N-terminal JAZ-interaction domain; the Jas motif of JAZ docks into the MYC3 N-terminal fold. Reason: Generic protein binding is uninformative. The partner is a JAZ protein, which acts as a transcriptional corepressor of MYC factors; transcription corepressor binding captures the functional meaning of this interaction. Proposed replacements: transcription corepressor binding Supporting Evidence: PMID:26258305 Here we show that Arabidopsis MYC3 undergoes pronounced conformational changes when bound to the conserved Jas motif of the JAZ9 repressor. PMID:21321051 MYC3 and MYC4 interact not only with JAZ1 but also with other JAZ proteins (JAZ3 and JAZ9) in both yeast two-hybrid and pull-down assays. |
| GO:0005515 protein binding | IPI PMID:26258305 Structural basis of JAZ repression of MYC transcription fact... | MODIFY | Summary: MYC3 binds JAZ repressors through its N-terminal JAZ-interaction domain; the Jas motif of JAZ docks into the MYC3 N-terminal fold. Reason: Generic protein binding is uninformative. The partner is a JAZ protein, which acts as a transcriptional corepressor of MYC factors; transcription corepressor binding captures the functional meaning of this interaction. Proposed replacements: transcription corepressor binding Supporting Evidence: PMID:26258305 Here we show that Arabidopsis MYC3 undergoes pronounced conformational changes when bound to the conserved Jas motif of the JAZ9 repressor. PMID:21321051 MYC3 and MYC4 interact not only with JAZ1 but also with other JAZ proteins (JAZ3 and JAZ9) in both yeast two-hybrid and pull-down assays. |
| GO:0005515 protein binding | IPI PMID:31178399 Molecular Basis of Natural Variation in Photoperiodic Flower... | REMOVE | Summary: Interaction reported in a study of MYC3 repression of the florigen gene FT. Reason: The cached record is abstract-only; the abstract describes MYC3 binding to the ACGGAT motif in the FT locus and stabilization by DELLAs, and the specific protein-protein assay behind this row is not visible. Generic protein binding adds no functional information, and removal does not imply the interaction is false; the FT-regulatory role is better captured by transcription factor and flowering annotations. Supporting Evidence: PMID:31178399 MYC3 is stabilized by DELLAs in the gibberellin pathway to suppress FT through binding the ACGGAT motif and antagonizing CONSTANS (CO) activation. |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: MYC3 is a nuclear protein, shown with GFP fusions in vivo. Reason: Nucleus is the site of MYC3 transcription factor activity. Supporting Evidence: PMID:21335373 we first confirmed their predicted nuclear localization in vivo using GFP fusions of both MYC3 and MYC4 proteins. |
| GO:0005634 nucleus | IDA PMID:21335373 The Arabidopsis bHLH transcription factors MYC3 and MYC4 are... | ACCEPT | Summary: MYC3 is a nuclear protein, shown with GFP fusions in vivo. Reason: Nucleus is the site of MYC3 transcription factor activity. Supporting Evidence: PMID:21335373 we first confirmed their predicted nuclear localization in vivo using GFP fusions of both MYC3 and MYC4 proteins. |
| GO:0005634 nucleus | IEA GO_REF:0000120 | ACCEPT | Summary: MYC3 is a nuclear protein, shown with GFP fusions in vivo. Reason: Nucleus is the site of MYC3 transcription factor activity. Supporting Evidence: PMID:21335373 we first confirmed their predicted nuclear localization in vivo using GFP fusions of both MYC3 and MYC4 proteins. |
| GO:0005634 nucleus | ISM GO_REF:0000122 | ACCEPT | Summary: MYC3 is a nuclear protein, shown with GFP fusions in vivo. Reason: Nucleus is the site of MYC3 transcription factor activity. Supporting Evidence: PMID:21335373 we first confirmed their predicted nuclear localization in vivo using GFP fusions of both MYC3 and MYC4 proteins. |
| GO:0006355 regulation of DNA-templated transcription | IBA GO_REF:0000033 | ACCEPT | Summary: MYC3 regulates transcription of jasmonate-responsive genes. Reason: Correct general process for a DNA-binding transcription factor; the more specific positive-regulation term is supported by IDA (PMID:21321051). Supporting Evidence: PMID:21335373 Our results show that MYC3 and MYC4 are activators of JA-regulated programs that act additively with MYC2 to regulate specifically different subsets of the JA-dependent transcriptional response. |
| GO:0006355 regulation of DNA-templated transcription | IEA GO_REF:0000120 | ACCEPT | Summary: MYC3 regulates transcription of jasmonate-responsive genes. Reason: Correct general process for a DNA-binding transcription factor; the more specific positive-regulation term is supported by IDA (PMID:21321051). Supporting Evidence: PMID:21335373 Our results show that MYC3 and MYC4 are activators of JA-regulated programs that act additively with MYC2 to regulate specifically different subsets of the JA-dependent transcriptional response. |
| GO:0006355 regulation of DNA-templated transcription | TAS PMID:11118137 Arabidopsis transcription factors: genome-wide comparative a... | ACCEPT | Summary: MYC3 regulates transcription of jasmonate-responsive genes. Reason: Correct general process for a DNA-binding transcription factor; the more specific positive-regulation term is supported by IDA (PMID:21321051). Supporting Evidence: PMID:21335373 Our results show that MYC3 and MYC4 are activators of JA-regulated programs that act additively with MYC2 to regulate specifically different subsets of the JA-dependent transcriptional response. |
| GO:0006952 defense response | IMP PMID:21335373 The Arabidopsis bHLH transcription factors MYC3 and MYC4 are... | KEEP AS NON CORE | Summary: myc2 myc3 myc4 triple mutants are as impaired as coi1-1 in defense against bacterial pathogens and insect herbivory. Reason: Defense is a major physiological output of MYC3-driven JA transcription; non-core relative to the TF activity. Supporting Evidence: PMID:21335373 the triple mutant myc2 myc3 myc4 is as impaired as coi1-1 in the activation of several, but not all, JA-mediated responses such as the defense against bacterial pathogens and insect herbivory. |
| GO:0009718 anthocyanin-containing compound biosynthetic process | IMP PMID:21321051 Characterization of JAZ-interacting bHLH transcription facto... | KEEP AS NON CORE | Summary: MYC3 overexpression increases anthocyanin accumulation. Reason: Gain-of-function phenotype reflecting downstream JA-regulated metabolism; non-core. Supporting Evidence: PMID:21321051 transgenic plants overexpressing MYC3 and MYC4 had higher levels of anthocyanin compared to the wild-type plants. |
| GO:0009753 response to jasmonic acid | IMP PMID:21321051 Characterization of JAZ-interacting bHLH transcription facto... | MODIFY | Summary: MYC3 overexpression causes root hypersensitivity to JA, and myc3 enhances JA insensitivity of myc2. Reason: As for MYC2, the informative process is that MYC3 is a downstream transcriptional effector in the jasmonic acid mediated signaling pathway rather than a generic response-to-chemical term. Proposed replacements: jasmonic acid mediated signaling pathway Supporting Evidence: PMID:21321051 In addition, roots of MYC3 overexpression plants were hypersensitive to JA. PMID:21335373 Our results show that MYC3 and MYC4 are activators of JA-regulated programs that act additively with MYC2 to regulate specifically different subsets of the JA-dependent transcriptional response. |
| GO:0010374 stomatal complex development | IGI PMID:29496884 Jasmonate Negatively Regulates Stomatal Development in Arabi... | KEEP AS NON CORE | Summary: MYC2, MYC3 and MYC4 redundantly mediate jasmonate inhibition of stomatal development upstream of SPEECHLESS and FAMA. Reason: Developmental output of MYC-dependent JA signaling; non-core. Supporting Evidence: PMID:29496884 three MYC transcription factors involved in jasmonate signaling, MYC2, MYC3, and MYC4, were found to redundantly modulate jasmonate-inhibited stomatal development. |
| GO:0043425 bHLH transcription factor binding | IPI PMID:21335373 The Arabidopsis bHLH transcription factors MYC3 and MYC4 are... | KEEP AS NON CORE | Summary: MYC3 forms heterodimers with MYC4 and MYC2. Reason: bHLH dimerization is a structural prerequisite for MYC DNA binding; correct but subsidiary to the core transcription factor activity. Supporting Evidence: PMID:21335373 We show that MYC3 and MYC4 interact in vitro and in vivo with JAZ repressors and also form homo- and heterodimers with MYC2 and among themselves. |
| GO:0045893 positive regulation of DNA-templated transcription | IDA PMID:21321051 Characterization of JAZ-interacting bHLH transcription facto... | ACCEPT | Summary: MYC3 activates JAZ promoter-GUS reporters in protoplast transactivation assays. Reason: Direct evidence that MYC3 is a transcriptional activator; core process. Supporting Evidence: PMID:21321051 MYC2, MYC3, and MYC4 were all capable of inducing expression of JAZ::GUS reporter constructs following transfection of carrot protoplasts. |
| GO:0046983 protein dimerization activity | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: Electronic inference from the bHLH domain that MYC3 dimerizes. Reason: Supported by experimental homo- and heterodimerization; subsidiary to core TF activity. Supporting Evidence: PMID:21335373 We show that MYC3 and MYC4 interact in vitro and in vivo with JAZ repressors and also form homo- and heterodimers with MYC2 and among themselves. |
| GO:0106167 extracellular ATP signaling | IMP PMID:30630869 Extracellular ATP Shapes a Defense-Related Transcriptome Bot... | KEEP AS NON CORE | Summary: MYC transcription factors are required for part of the extracellular ATP-induced transcriptional response. Reason: Downstream/crosstalk output; non-core. Supporting Evidence: PMID:30630869 demonstrating that MYCs acting downstream of the jasmonate receptor complex and calmodulin-binding transcription activators are nuclear transducers of P2K1-mediated extracellular ATP signaling |
Loading supporting content…
Download this section (compressed HTML)Q: Which jasmonate-responsive targets are preferentially controlled by MYC3 rather than MYC2 or MYC4, given their nearly identical DNA-binding specificity?
Q: Is MYC3 repression of FT mechanistically linked to JAZ-MYC3 regulation, i.e. does jasmonate signaling affect flowering time through MYC3?
Experiment: Genome-wide binding (ChIP-seq/DAP-seq) of MYC2, MYC3 and MYC4 in matched tissues with and without JA-Ile, combined with single and higher-order mutant transcriptomes.
Hypothesis: MYC3 shares most binding sites with MYC2 but contributes uniquely to specific target subsets through tissue-specific expression and partner availability.
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)