CAULIFLOWER (CAL; AGL10) is a MIKC-type MADS-domain transcription factor of the SQUAMOSA/AP1 clade and the closest Arabidopsis paralog of APETALA1. It is expressed in young flower primordia, where it acts partially redundantly with AP1 (and, more weakly, with FRUITFULL) to assign floral meristem identity to the lateral meristems produced by the inflorescence meristem. cal single mutants have essentially wild-type flowers, but ap1 cal double mutants convert every flower into a reiterating inflorescence-like meristem (the "cauliflower" curd), and ap1 cal ful triple mutants fail to make flowers at all. CAL promotes floral fate in part by up-regulating LEAFY and repressing TERMINAL FLOWER1 in floral primordia, and it forms heterodimers with other MADS proteins such as SOC1. The cauliflower phenotype of Brassica oleracea var. botrytis is associated with a non-functional CAL ortholog.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000977 RNA polymerase II transcription regulatory region sequence-specific DNA binding | IEA GO_REF:0000002 | ACCEPT | Summary: RNA polymerase II regulatory-region sequence-specific DNA binding, mapped from the SRF-like/MADS InterPro domain. Reason: CAL has an intact MADS DNA-binding domain and acts as a sequence-specific transcription factor; the domain-based mapping is appropriate. Supporting Evidence: PMID:7824951 Like APETALA1, CAULIFLOWER is expressed in young flower primordia and encodes a MADS-domain, indicating that it may function as a transcription factor. |
| GO:0000978 RNA polymerase II cis-regulatory region sequence-specific DNA binding | IBA GO_REF:0000033 | ACCEPT | Summary: Cis-regulatory region sequence-specific DNA binding inferred by PAINT from the MADS-box family. Reason: IBA for the MADS-box transcription factor PANTHER node PTN000235373; CAL is a canonical MIKC-type MADS-domain protein. The MADS domain binds CArG-box cis-elements; CAL lies inside the clade that inherited this activity and retains the domain. Supporting Evidence: PMID:7824951 Like APETALA1, CAULIFLOWER is expressed in young flower primordia and encodes a MADS-domain, indicating that it may function as a transcription factor. |
| GO:0000981 DNA-binding transcription factor activity, RNA polymerase II-specific | IBA GO_REF:0000033 | ACCEPT | Summary: DNA-binding transcription factor activity (RNA polymerase II-specific) inferred by PAINT; this is the core molecular function of CAL. Reason: IBA for the MADS-box transcription factor PANTHER node PTN000235373; CAL is a canonical MIKC-type MADS-domain protein. Genetic data show CAL acts redundantly with AP1 and FUL to control LFY and TFL1 expression domains, consistent with transcription factor activity. Supporting Evidence: PMID:10648231 Our results suggest that the FUL, AP1 and CAL genes act redundantly to control inflorescence architecture by affecting the domains of LFY and TFL1 expression as well as the relative levels of their activities. |
| GO:0003677 DNA binding | IEA GO_REF:0000002 | MODIFY | Summary: Generic DNA binding from MADS-domain InterPro mappings. Reason: Correct but uninformative; the more specific cis-regulatory region sequence-specific DNA binding term is already supported for CAL. Proposed replacements: RNA polymerase II cis-regulatory region sequence-specific DNA binding |
| GO:0003700 DNA-binding transcription factor activity | IEA GO_REF:0000002 | ACCEPT | Summary: DNA-binding transcription factor activity from the MADS-box InterPro entry. Reason: Correct for a MADS-box factor; the RNA polymerase II-specific child term (GO:0000981, IBA) is the more specific core annotation. |
| GO:0003700 DNA-binding transcription factor activity | ISS PMID:11118137 Arabidopsis transcription factors: genome-wide comparative a... | ACCEPT | Summary: Transcription factor activity assigned from the genome-wide Arabidopsis transcription factor catalogue. Reason: Sequence-similarity based classification of CAL as a MADS transcription factor is sound, although less specific than the RNA polymerase II-specific term. Supporting Evidence: PMID:11118137 Arabidopsis dedicates over 5% of its genome to code for more than 1500 transcription factors, about 45% of which are from families specific to plants. |
| GO:0003700 DNA-binding transcription factor activity | ISS PMID:12837945 Molecular and phylogenetic analyses of the complete MADS-box... | ACCEPT | Summary: Transcription factor activity assigned from the phylogenetic survey of the Arabidopsis MADS-box family. Reason: CAL is a MIKC-type MADS-box gene in this family survey; similarity-based assignment of transcription factor activity is sound. Supporting Evidence: PMID:12837945 MADS-box transcription factors are key regulators of several plant development processes. |
| GO:0003700 DNA-binding transcription factor activity | TAS PMID:7824951 Molecular basis of the cauliflower phenotype in Arabidopsis. | ACCEPT | Summary: Transcription factor activity stated in the paper reporting the cloning of CAL. Reason: The CAL cloning paper identifies a MADS domain and proposes transcription factor function; consistent with all later work on the AP1/CAL/FUL clade. Supporting Evidence: PMID:7824951 Like APETALA1, CAULIFLOWER is expressed in young flower primordia and encodes a MADS-domain, indicating that it may function as a transcription factor. |
| GO:0005515 protein binding | IPI PMID:11439126 APETALA1 and SEPALLATA3 interact to promote flower developme... | MODIFY | Summary: IntAct records a CAL-SOC1 interaction from the AP1/CAL yeast two-hybrid screen. Reason: The screen used AP1 and CAL as baits to find MADS partners; MADS proteins act as heterodimers, so protein heterodimerization activity is more informative than protein binding. The full text was not available locally, so the curator's partner assignment is accepted as recorded. Proposed replacements: protein heterodimerization activity Supporting Evidence: PMID:11439126 Studies of MADS-domain proteins in diverse species have shown that they often function as heterodimers or in larger ternary complexes, suggesting that additional proteins may interact with AP1 and CAL during flower development. |
| GO:0005515 protein binding | IPI PMID:15805477 Comprehensive interaction map of the Arabidopsis MADS Box tr... | MODIFY | Summary: CAL-SOC1 interaction from the matrix yeast two-hybrid map of Arabidopsis MADS proteins. Reason: The matrix screen reports specific MADS heterodimers; protein heterodimerization activity captures the CAL-SOC1 interaction better than protein binding. Proposed replacements: protein heterodimerization activity Supporting Evidence: PMID:15805477 A matrix-based yeast two-hybrid screen of >100 members of this family revealed a collection of specific heterodimers and a few homodimers. |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: Nucleus (is_active_in) inferred by PAINT for MADS-box transcription factors. Reason: MADS-domain transcription factors act on chromatin in the nucleus; consistent with CAL function. |
| GO:0005634 nucleus | IEA GO_REF:0000120 | ACCEPT | Summary: Nucleus from InterPro/UniProt subcellular location mapping. Reason: Consistent with the nuclear location of MADS transcription factors. |
| GO:0005634 nucleus | ISM GO_REF:0000122 | ACCEPT | Summary: Nucleus predicted by AtSubP. Reason: Prediction is consistent with the expected nuclear location of a MADS transcription factor. |
| GO:0006355 regulation of DNA-templated transcription | IEA GO_REF:0000002 | MODIFY | Summary: Regulation of DNA-templated transcription from InterPro. Reason: Correct but general; regulation of transcription by RNA polymerase II is already supported by IBA and is more specific. Proposed replacements: regulation of transcription by RNA polymerase II |
| GO:0006357 regulation of transcription by RNA polymerase II | IBA GO_REF:0000033 | ACCEPT | Summary: Regulation of transcription by RNA polymerase II inferred by PAINT. Reason: IBA for the MADS-box transcription factor PANTHER node PTN000235373; CAL is a canonical MIKC-type MADS-domain protein. |
| GO:0009911 positive regulation of flower development | TAS PMID:10648231 Redundant regulation of meristem identity and plant architec... | ACCEPT | Summary: Positive regulation of flower development (TAS) from the study of FUL/AP1/CAL redundancy. Reason: ap1 cal ful triple mutants make leafy shoots in place of flowers, so CAL (redundantly with AP1 and FUL) is required for flower formation; this is the closest available process term for its floral meristem identity role. Supporting Evidence: PMID:10648231 We have found that mutations in the FRUITFULL (FUL) MADS-box gene, when combined with mutations in AP1 and CAL, lead to a dramatic non-flowering phenotype in which plants continuously elaborate leafy shoots in place of flowers. |
| GO:0010582 floral meristem determinacy | IBA GO_REF:0000033 | ACCEPT | Summary: Floral meristem determinacy inferred by PAINT at node PTN001734081, seeded by CAL (AT1G26310) and its paralog AP1 (AT1G69120). Reason: ap1 cal flowers are converted into indeterminate, reiterating inflorescence-like meristems, so the CAL + AP1 seed of the node matches the double-mutant genetics; CAL appears in its own WITH/FROM, which reflects its own experimental grounding for the PAINT node rather than circularity. Supporting Evidence: PMID:7824951 Genetic studies demonstrate that two Arabidopsis genes, CAULIFLOWER and APETALA1, encode partially redundant activities involved in the formation of floral meristems, the first step in the development of flowers. |
| GO:0010582 floral meristem determinacy | IEP PMID:20626659 Arabidopsis BLADE-ON-PETIOLE1 and 2 promote floral meristem ... | ACCEPT | Summary: Floral meristem determinacy (IEP) from the BOP1/BOP2 study. Reason: The process assignment is correct for CAL (see IBA and genetic data). The IEP evidence itself is weak (expression change), and the full text was not available locally, so the curator's call is retained. Supporting Evidence: PMID:20626659 Loss-of-function bop1 bop2 mutants show subtle defects in inflorescence and floral architecture but in combination with lfy or ap1, synergistic defects in floral meristem fate and determinacy are revealed. |
| GO:0045944 positive regulation of transcription by RNA polymerase II | IEA GO_REF:0000002 | ACCEPT | Summary: Positive regulation of transcription by RNA polymerase II from InterPro (SQUAMOSA-type MADS). Reason: AP1/CAL up-regulate LFY expression, consistent with a positive transcriptional role. Supporting Evidence: PMID:10648231 The closely related APETALA1 (AP1) and CAULIFLOWER (CAL) meristem identity genes are also important for flower initiation, in part because of their roles in upregulating LFY expression. |
| GO:0046983 protein dimerization activity | IEA GO_REF:0000002 | ACCEPT | Summary: Protein dimerization activity from MADS/K-domain InterPro mappings. Reason: MIKC proteins dimerize through the MADS and K domains, and CAL is documented both as a homodimer and in heterodimers (e.g. with SOC1 in yeast two-hybrid assays). The family-level term captures that dimerization capability; the more specific protein heterodimerization activity is used on the partner-specific protein binding rows where the source identifies a MADS partner. Supporting Evidence: PMID:15805477 A matrix-based yeast two-hybrid screen of >100 members of this family revealed a collection of specific heterodimers and a few homodimers. |
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Download this section (compressed HTML)Q: Does CAL bind the same CArG-box targets as AP1 genome-wide (e.g., at LFY, TFL1, SOC1, AGL24, SVP), or does its weaker single-mutant phenotype reflect lower expression rather than distinct target specificity?
Q: Is a GO process term for floral meristem identity specification (distinct from floral meristem determinacy) warranted for the AP1/CAL/FUL clade?
Experiment: ChIP-seq of tagged CAL expressed from its native promoter in an ap1 background to determine whether CAL occupies AP1 target loci and can explain the partial rescue of floral identity.
Type: ChIP-seq
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