GAI (GIBBERELLIC ACID INSENSITIVE) is one of five Arabidopsis DELLA-subfamily proteins of the GRAS family and functions as a nuclear growth-repressor in the gibberellin (GA) signaling pathway. GAI lacks a DNA-binding domain and acts through protein-protein interactions. Its N-terminal DELLA domain serves as the receiver for GA-activated GID1 receptors, and its C-terminal GRAS domain mediates interactions with diverse transcription factors and cofactors. GAI represses GA responses both by titrating growth-promoting transcription factors (such as PIFs and BZR1) and by acting as a transcriptional coactivator of DNA-binding IDD-family transcription factors (GAF1/IDD2, ENY/IDD1) at GA-feedback genes such as GA20OX2, thereby controlling GA homeostasis. When GA levels rise, GA-GID1 binding promotes DELLA recognition and ubiquitin-proteasome degradation, derepressing growth. GAI acts redundantly with its closest paralog RGA in repressing vegetative elongation and floral induction, and additionally participates in seed germination, prefoldin-mediated cortical microtubule organization, photoperiodic flowering (via CONSTANS), and male reproductive development. GAI is the Arabidopsis orthologue of the cereal green revolution Rht/d8 dwarfing genes.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005634 nucleus | IEA GO_REF:0000044 | ACCEPT | Summary: Nuclear localization, electronically mapped from UniProt subcellular location. Strongly supported by direct experimental evidence for GAI and the DELLA family. Reason: GAI is a nuclear DELLA protein; nuclear localization is experimentally established and the IEA mapping is correct. Supporting Evidence: PMID:12492836 We also show that neither of the two putative nuclear localisation signals contained in DELLA proteins are individually necessary for nuclear localisation of GAI. |
| GO:0009740 gibberellic acid mediated signaling pathway | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA electronic annotation placing GAI in the GA signaling pathway. Correct and central to GAI function, though more specific (negative regulation) terms are also annotated. Reason: GAI is a bona fide component (repressor) of the GA-mediated signaling pathway. Supporting Evidence: PMID:11606552 RGA and GAI are negative regulators of the gibberellin (GA) signal transduction pathway in Arabidopsis thaliana. |
| GO:0005515 protein binding | IPI PMID:15155881 The Arabidopsis F-box protein SLEEPY1 targets gibberellin si... | KEEP AS NON CORE | Summary: Interaction with the F-box protein GID2/SLY1 (SCF E3 ligase substrate receptor). Real interaction but the generic protein binding term is uninformative. Reason: Valid physical interaction (GAI-GID2/SLY1) but protein binding conveys no specific function; retained as non-core supporting evidence. Supporting Evidence: PMID:15155881 The Arabidopsis F-box protein SLEEPY1 targets gibberellin signaling repressors for gibberellin-induced degradation. |
| GO:0005515 protein binding | IPI PMID:15161962 The Arabidopsis mutant sleepy1gar2-1 protein promotes plant ... | KEEP AS NON CORE | Summary: Interaction with the SLY1/SCF E3 ligase machinery affecting DELLA degradation. Generic protein-binding term. Reason: Documents a real GAI-SLY1/SCF interaction but is uninformative as a molecular function. Supporting Evidence: PMID:15161962 increasing the affinity of the SCFSLY1 E3 ubiquitin ligase for DELLA protein substrates |
| GO:0005515 protein binding | IPI PMID:16709201 Identification and characterization of Arabidopsis gibberell... | KEEP AS NON CORE | Summary: GA-dependent interaction between GAI (DELLA) and the GID1 GA receptors. Mechanistically important but captured only as generic protein binding. Reason: Real, functionally important GAI-GID1 interaction, but a more specific term (GA receptor binding) would be preferable; protein binding is non-core. Supporting Evidence: PMID:16709201 in vivo interaction in the presence of GA(4) between each AtGID1 and the Arabidopsis DELLA proteins |
| GO:0005515 protein binding | IPI PMID:17194763 Genetic characterization and functional analysis of the GID1... | KEEP AS NON CORE | Summary: Genetic/biochemical analysis of GID1 receptors interacting with DELLAs. Generic protein-binding annotation. Reason: Supports GAI-GID1 interaction; uninformative as a stand-alone MF. Supporting Evidence: PMID:17194763 Genetic characterization and functional analysis of the GID1 gibberellin receptors in Arabidopsis. |
| GO:0005515 protein binding | IPI PMID:17416730 The DELLA domain of GA INSENSITIVE mediates the interaction ... | KEEP AS NON CORE | Summary: The GAI DELLA domain mediates GA-dependent interaction with the GID1A receptor (DELLA domain as receiver domain). Important interaction, generic term. Reason: Documents the functionally critical GAI DELLA-domain/GID1A interaction; generic protein binding is non-core. Supporting Evidence: PMID:17416730 the GAI DELLA domain alone can mediate GA-dependent GID1A interactions |
| GO:0005515 protein binding | IPI PMID:18216856 Coordinated regulation of Arabidopsis thaliana development b... | KEEP AS NON CORE | Summary: Interaction in the context of coordinated light and GA regulation of development. Generic protein-binding term. Reason: Supports a DELLA protein interaction; uninformative MF term. Supporting Evidence: PMID:18216856 Coordinated regulation of Arabidopsis thaliana development by light and gibberellins. |
| GO:0005515 protein binding | IPI PMID:18827182 Proteolysis-independent downregulation of DELLA repression i... | KEEP AS NON CORE | Summary: Proteolysis-independent downregulation of DELLA repression by GID1 (GA receptor) interaction. Generic protein-binding term. Reason: Real GAI-GID1 interaction context; non-informative as MF. Supporting Evidence: PMID:18827182 Proteolysis-independent downregulation of DELLA repression in Arabidopsis by the gibberellin receptor GIBBERELLIN INSENSITIVE DWARF1. |
| GO:0005515 protein binding | IPI PMID:19037309 Gibberellin-induced DELLA recognition by the gibberellin rec... | KEEP AS NON CORE | Summary: Crystal structure of GID1A-GA-GAI(DELLA domain) ternary complex defining GA-induced DELLA recognition. Structurally validated interaction, generic term. Reason: High-quality structural evidence for GAI-GID1 binding, but encoded only as generic protein binding. Supporting Evidence: PMID:19037309 the amino-terminal DELLA domain of GAI |
| GO:0005515 protein binding | IPI PMID:19500306 Differential expression and affinities of Arabidopsis gibber... | KEEP AS NON CORE | Summary: Differential affinities of GID1 receptors for DELLAs. Generic protein-binding annotation. Reason: Supports GAI-GID1 interaction variation; uninformative as MF. Supporting Evidence: PMID:19500306 Differential expression and affinities of Arabidopsis gibberellin receptors |
| GO:0005515 protein binding | IPI PMID:21798944 Evidence for network evolution in an Arabidopsis interactome... | KEEP AS NON CORE | Summary: High-throughput Arabidopsis interactome (Y2H) interaction. Generic protein-binding term from a large-scale screen. Reason: Large-scale interactome interaction; valid but uninformative as a specific MF. Supporting Evidence: PMID:21798944 Evidence for network evolution in an Arabidopsis interactome map. |
| GO:0005515 protein binding | IPI PMID:22820377 Brassinosteroid, gibberellin and phytochrome impinge on a co... | KEEP AS NON CORE | Summary: DELLA interactions within a brassinosteroid/GA/phytochrome transcription module (e.g. BZR1, PIFs). Generic protein-binding annotation. Reason: Supports functionally relevant DELLA-TF interactions, but the term is uninformative. Supporting Evidence: PMID:22820377 Brassinosteroid, gibberellin and phytochrome impinge on a common transcription module in Arabidopsis. |
| GO:0005515 protein binding | IPI PMID:26801684 DELLA proteins physically interact with CONSTANS to regulate... | KEEP AS NON CORE | Summary: DELLA-CONSTANS (CO) physical interaction linking GA and photoperiod flowering. Generic protein-binding term. Reason: Real GAI/DELLA-CO interaction relevant to flowering; uninformative as a generic MF. Supporting Evidence: PMID:26801684 DELLA proteins physically interact with CONSTANS (CO) |
| GO:0005515 protein binding | IPI PMID:28650476 CrY2H-seq: a massively multiplexed assay for deep-coverage i... | KEEP AS NON CORE | Summary: CrY2H-seq large-scale interactome interaction. Generic protein-binding term from high-throughput screen. Reason: Large-scale interaction evidence; valid but non-specific. Supporting Evidence: PMID:28650476 CrY2H-seq: a massively multiplexed assay for deep-coverage interactome mapping. |
| GO:0005515 protein binding | IPI PMID:32612234 Extensive signal integration by the phytohormone protein net... | KEEP AS NON CORE | Summary: Phytohormone protein interaction network. Generic protein-binding term from a network study. Reason: Network interaction evidence; uninformative as a specific MF. Supporting Evidence: PMID:32612234 Extensive signal integration by the phytohormone protein network. |
| GO:0005515 protein binding | IPI PMID:40755058 A DELLA-ANAC106 reciprocal negative feedback circuit modulat... | KEEP AS NON CORE | Summary: DELLA-ANAC106 physical interaction within a reciprocal negative feedback circuit controlling GA homeostasis and male fertility. Generic protein-binding term. Reason: Real, functionally relevant DELLA-ANAC106 interaction; uninformative as generic MF. Supporting Evidence: PMID:40755058 DELLA proteins physically interact with ANAC106 in a dose-dependent manner, inhibiting its transcriptional activation capacity |
| GO:0045944 positive regulation of transcription by RNA polymerase II | IDA PMID:25035403 DELLAs function as coactivators of GAI-ASSOCIATED FACTOR1 in... | ACCEPT | Summary: GAI/DELLA acts as a coactivator of the DNA-binding TF GAF1, positively regulating transcription of GA-feedback genes. Supported by direct experimental evidence. Reason: GAI coactivates GAF1-dependent transcription of target genes; consistent with the demonstrated coactivator role. Supporting Evidence: PMID:25035403 DELLAs promote the transcription of genes encoding GA biosynthetic enzymes and GA receptors as coactivators of a DNA binding transcription factor, GAF1 |
| GO:0005515 protein binding | IPI PMID:23583555 Dynamic regulation of cortical microtubule organization thro... | KEEP AS NON CORE | Summary: Physical interaction with prefoldin subunits PFD3/PFD5 in the nucleus, regulating cortical microtubule organization. Generic protein-binding term. Reason: Real, functionally relevant GAI-prefoldin interaction; uninformative as a generic MF. Supporting Evidence: PMID:23583555 physical interaction between the nuclear-localized DELLA proteins and the prefoldin complex file:ARATH/GAI/GAI-deep-research-falcon.md GAI binds prefoldin subunits PFD5 and PFD3 |
| GO:0005634 nucleus | IDA PMID:23583555 Dynamic regulation of cortical microtubule organization thro... | ACCEPT | Summary: Direct evidence that GAI/DELLA is nuclear-localized (and recruits prefoldin to the nucleus in the absence of GA). Reason: Direct experimental support for nuclear localization of GAI. Supporting Evidence: PMID:23583555 physical interaction between the nuclear-localized DELLA proteins and the prefoldin complex file:ARATH/GAI/GAI-deep-research-falcon.md DELLA proteins including GAI are nuclear-localized transcription regulators |
| GO:0000976 transcription cis-regulatory region binding | IPI PMID:25533953 An Arabidopsis gene regulatory network for secondary cell wa... | MARK AS OVER ANNOTATED | Summary: Derived from a large yeast-one-hybrid (Y1H) protein-DNA screen of a secondary cell wall gene regulatory network in which GRAS-family TFs were over-represented. However, DELLA proteins (including GAI) lack a DNA-binding domain and do not bind DNA sequence-specifically, so a direct cis-region-binding molecular function is mechanistically implausible for GAI. Reason: GAI lacks a DNA-binding domain; DELLAs associate with promoters only indirectly via DNA-binding partners. A Y1H positive does not establish direct, sequence-specific DNA binding by GAI, so this MF is an over-annotation. Supporting Evidence: PMID:25035403 although DELLAs lack known DNA binding motifs PMID:24989044 DELLAs are nuclear proteins lacking a DNA binding domain file:ARATH/GAI/GAI-deep-research-falcon.md DELLAs lack canonical DNA-binding motifs but regulate transcription through protein-protein interactions and chromatin association |
| GO:0005515 protein binding | IPI PMID:24989044 Arabidopsis DELLA and two HD-ZIP transcription factors regul... | KEEP AS NON CORE | Summary: Direct interaction of GAI/DELLA with HD-ZIP transcription factors ATML1 and PDF2 in the epidermal germination module. Generic protein-binding term. Reason: Real, functionally relevant GAI-ATML1/PDF2 interaction; uninformative as a generic MF. Supporting Evidence: PMID:24989044 DELLA proteins interact directly with ATML1 and its paralogue PDF2 |
| GO:0010029 regulation of seed germination | IEP PMID:24989044 Arabidopsis DELLA and two HD-ZIP transcription factors regul... | ACCEPT | Summary: GAI/DELLA participates in epidermal GA signaling affecting seed germination (release of ATML1/PDF2 upon DELLA loss enhances germination potential). GAI is a redundant contributor (RGL2 dominates germination repression). Reason: GAI contributes to regulation of germination via the epidermal GA-signaling module; supported by direct experimental evidence. Supporting Evidence: PMID:24989044 increased GA levels reduce DELLA protein abundance and release ATML1/PDF2 to activate L1 box gene expression, thus enhancing germination potential |
| GO:2000033 regulation of seed dormancy process | IEP PMID:24989044 Arabidopsis DELLA and two HD-ZIP transcription factors regul... | KEEP AS NON CORE | Summary: GAI/DELLA involvement in GA-regulated seed dormancy/germination. Supporting, non-core developmental role. Reason: GAI participates in GA-mediated dormancy/germination control redundantly with other DELLAs; non-core. Supporting Evidence: PMID:24989044 increased GA levels reduce DELLA protein abundance and release ATML1/PDF2 to activate L1 box gene expression, thus enhancing germination potential |
| GO:0005634 nucleus | ISM GO_REF:0000122 | ACCEPT | Summary: Predicted nuclear localization (AtSubP). Consistent with abundant experimental evidence for nuclear GAI. Reason: Sequence-based prediction concordant with experimentally established nuclear localization. Supporting Evidence: PMID:12492836 nuclear localisation of GAI |
| GO:0003713 transcription coactivator activity | IDA PMID:25035403 DELLAs function as coactivators of GAI-ASSOCIATED FACTOR1 in... | ACCEPT | Summary: GAI/DELLA functions as a transcriptional coactivator of the DNA-binding IDD-family TF GAF1 (and ENY/IDD1) at GA-feedback genes. This is GAI's best-supported molecular function, exerted via protein-protein interaction rather than DNA binding. Reason: Directly demonstrated coactivator activity; represents the core molecular function of GAI consistent with its lack of a DNA-binding domain. Supporting Evidence: PMID:25035403 DELLAs and TOPLESS-RELATED (TPR) act as coactivators and a corepressor of GAF1, respectively file:ARATH/GAI/GAI-deep-research-falcon.md GAI physically interacts with GAF1/IDD-family factors and TPR4 |
| GO:0005515 protein binding | IPI PMID:25035403 DELLAs function as coactivators of GAI-ASSOCIATED FACTOR1 in... | KEEP AS NON CORE | Summary: Physical interaction of GAI with the GAF1/IDD2 (and ENY/IDD1) DNA-binding transcription factors. Generic protein-binding term underlying the coactivator function. Reason: Real, central GAI-GAF1 interaction, but encoded only as generic protein binding; the coactivator MF (GO:0003713) captures the function. Supporting Evidence: PMID:25035403 we identified an Arabidopsis thaliana DELLA binding transcription factor, GAI-ASSOCIATED FACTOR1 (GAF1) |
| GO:0005634 nucleus | IDA PMID:25035403 DELLAs function as coactivators of GAI-ASSOCIATED FACTOR1 in... | ACCEPT | Summary: Direct evidence of nuclear GAI in the GAF1 coactivation study. Well supported. Reason: Direct experimental support for nuclear localization. Supporting Evidence: PMID:25035403 DELLAs localize in the nucleus |
| GO:0009939 positive regulation of gibberellic acid mediated signaling pathway | IDA PMID:25035403 DELLAs function as coactivators of GAI-ASSOCIATED FACTOR1 in... | KEEP AS NON CORE | Summary: Through GAF1 coactivation of GA biosynthetic (GA20OX2) and GA receptor genes, GAI/DELLA participates in GA feedback regulation. Annotated as positive regulation in the homeostatic/feedback context. Reason: Captures GAI's role in GA feedback (homeostasis) via coactivation; biologically supported but secondary to its dominant role as a negative regulator of GA signaling. Supporting Evidence: PMID:25035403 GAF1 binds to genes that are subject to GA feedback regulation |
| GO:0010336 gibberellic acid homeostasis | IDA PMID:25035403 DELLAs function as coactivators of GAI-ASSOCIATED FACTOR1 in... | ACCEPT | Summary: GAI/DELLA-GAF1 coactivation of GA metabolic and receptor genes provides the mechanism for GA feedback homeostasis. Core process. Reason: Directly demonstrated role in GA homeostasis via the DELLA-GAF1 feedback module. Supporting Evidence: PMID:25035403 providing a mechanism for the integrative regulation of plant growth and GA homeostasis file:ARATH/GAI/GAI-deep-research-falcon.md DELLA proteins directly upregulate early GA-responsive targets including GA biosynthetic/receptor genes and XERICO |
| GO:0033206 meiotic cytokinesis | IMP PMID:27621423 Gibberellin Induces Diploid Pollen Formation by Interfering ... | KEEP AS NON CORE | Summary: rga gai double mutants phenocopy GA-induced defects in male meiotic cytokinesis (aberrant radial microtubule arrays, 2n pollen). GA/DELLA acts largely in somatic anther tissue, indicating an indirect, redundant developmental role for GAI. Reason: Genetic involvement is demonstrated but redundant with RGA and largely non-cell-autonomous; a peripheral developmental process for GAI rather than a core function. Supporting Evidence: PMID:27621423 Similar defects in meiotic cell division and reproductive ploidy stability occur in Arabidopsis plants depleted of RGA and GAI |
| GO:0009739 response to gibberellin | IMP PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: GAI is a repressor of GA responses; loss of GAI (with RGA) derepresses GA signaling, demonstrating involvement in the response to gibberellin. Reason: GAI is a central modulator of GA responses; well supported genetically. Supporting Evidence: PMID:11606552 Removing both RGA and GAI function allows for complete derepression of many aspects of GA signaling. |
| GO:0009739 response to gibberellin | IGI PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: Genetic interaction (rga gai, ga1-3) confirming GAI involvement in GA responses. Redundant pair of the IMP annotation from the same study. Reason: Genetic-interaction evidence consistent with GAI's role in GA responses. Supporting Evidence: PMID:11606552 the rga-24 and gai-t6 null mutations have a synergistic effect on plant growth |
| GO:0010628 positive regulation of gene expression | IGI PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | KEEP AS NON CORE | Summary: GAI/RGA loss increases feedback inhibition of a GA biosynthetic gene, and DELLAs activate sets of GA-feedback genes; broadly supports a positive gene-regulatory role. The term is very general. Reason: Supported but generic; GAI's specific positive regulation is better captured by coactivator activity and GA homeostasis terms. Supporting Evidence: PMID:11606552 caused increased feedback inhibition of expression of a GA biosynthetic gene |
| GO:0010629 negative regulation of gene expression | IMP PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | KEEP AS NON CORE | Summary: As a repressor of GA-induced gene expression, GAI negatively regulates expression of GA-responsive growth genes (e.g. by titrating PIFs). Supported but general. Reason: Consistent with GAI's repressor role; the term is generic relative to negative regulation of GA signaling. Supporting Evidence: PMID:11606552 RGA and GAI have partially redundant functions in maintaining the repressive state of the GA-signaling pathway |
| GO:0009909 regulation of flower development | IMP NOT PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: NOT annotation. In the rga gai double null, flower development defects of ga1-3 were NOT restored, indicating GAI is not required for (does not regulate) flower development in this context (RGL1/RGL2 dominate). Reason: The negation is directly supported - removing GAI (with RGA) did not rescue floral defects. Supporting Evidence: PMID:11606552 seed germination and flower development defects were not restored |
| GO:0009938 negative regulation of gibberellic acid mediated signaling pathway | IGI PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: GAI is a negative regulator of GA signaling; genetic interaction with RGA demonstrates this repressive role. This is a core function of GAI. Reason: Directly supported core function - GAI represses the GA signaling pathway. Supporting Evidence: PMID:11606552 RGA and GAI are negative regulators of the gibberellin (GA) signal transduction pathway in Arabidopsis thaliana. file:ARATH/GAI/GAI-deep-research-falcon.md GAI is one of five Arabidopsis DELLA repressors of GA responses |
| GO:0010029 regulation of seed germination | IMP NOT PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: NOT annotation. rga gai double null did not restore seed germination defects of ga1-3, indicating GAI is not the DELLA responsible for germination repression (RGL2 dominates). Reason: Negation directly supported by the genetic result. Supporting Evidence: PMID:11606552 seed germination and flower development defects were not restored |
| GO:0010029 regulation of seed germination | IGI NOT PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: NOT annotation (genetic interaction). Same conclusion - GAI loss does not rescue germination defects. Reason: Negation supported; consistent with the IMP NOT annotation from the same study. Supporting Evidence: PMID:11606552 seed germination and flower development defects were not restored |
| GO:0080154 regulation of fertilization | IMP NOT PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: NOT annotation. This study (PMID:11606552) concerns vegetative growth, germination and flower development; the negation of fertilization regulation is consistent with GAI not being required for reproductive/fertility defect rescue in this context. Reason: Negation consistent with the genetic data; GAI is not implicated in regulating fertilization in this study. Supporting Evidence: PMID:11606552 seed germination and flower development defects were not restored |
| GO:0080154 regulation of fertilization | IGI NOT PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: NOT annotation (genetic interaction), same negation as above. Reason: Negation consistent with genetic data. Supporting Evidence: PMID:11606552 seed germination and flower development defects were not restored |
| GO:1900033 negative regulation of trichome patterning | IGI PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | KEEP AS NON CORE | Summary: rga (and rga gai) loss rescues abaxial trichome initiation in ga1-3, implicating GAI/RGA in repressing GA-promoted trichome initiation. GAI's contribution is redundant/minor (RGA dominant). Reason: Genetic involvement in trichome patterning is supported but redundant and peripheral to GAI's core GA-signaling role. Supporting Evidence: PMID:11606552 Phenotypes rescued include abaxial trichome initiation |
| GO:1905613 regulation of developmental vegetative growth | IMP NOT PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: NOT annotation. gai-t6 single mutant alone has little effect on vegetative growth, so by itself GAI does not measurably regulate developmental vegetative growth (the effect requires combination with rga). Reason: Negation consistent with gai-t6 single-mutant having little phenotype; the regulatory effect emerges only with RGA. Supporting Evidence: PMID:11606552 Although gai-t6 alone has little effect, when combined with rga-24, they completely rescued the above defects |
| GO:1905614 negative regulation of developmental vegetative growth | IGI PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: With RGA, GAI represses GA-promoted vegetative growth (stem elongation, rosette radius); the rga gai double rescues these growth defects to WT/GA-overdose. Core repressive role on growth (redundant with RGA). Reason: Genetic-interaction evidence supports GAI's role in negatively regulating vegetative growth together with RGA. Supporting Evidence: PMID:11606552 when combined with rga-24, they completely rescued the above defects of ga1-3 to wild-type or GA-overdose phenotype |
| GO:1905622 negative regulation of leaf development | IGI PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | KEEP AS NON CORE | Summary: GAI/RGA repression of GA-promoted growth extends to leaf/rosette development; genetic interaction supports a redundant negative role in leaf development. Reason: Supported via genetic interaction but redundant and peripheral; non-core. Supporting Evidence: PMID:11606552 Phenotypes rescued include abaxial trichome initiation, rosette radius, flowering time, stem elongation, and apical dominance |
| GO:2000024 regulation of leaf development | IMP NOT PMID:11606552 Synergistic derepression of gibberellin signaling by removin... | ACCEPT | Summary: NOT annotation. Consistent with gai-t6 single mutant having little effect; GAI alone does not measurably regulate leaf development. Reason: Negation consistent with the minimal gai-t6 single-mutant phenotype. Supporting Evidence: PMID:11606552 Although gai-t6 alone has little effect |
| GO:0005634 nucleus | IDA PMID:12492836 Evidence that the Arabidopsis nuclear gibberellin signalling... | ACCEPT | Summary: Direct demonstration of GAI nuclear localization; neither putative NLS individually required. Strongly supported core localization. Reason: Direct experimental evidence for nuclear localization of GAI. Supporting Evidence: PMID:12492836 neither of the two putative nuclear localisation signals contained in DELLA proteins are individually necessary for nuclear localisation of GAI |
| GO:0009938 negative regulation of gibberellic acid mediated signaling pathway | IMP PMID:17416730 The DELLA domain of GA INSENSITIVE mediates the interaction ... | ACCEPT | Summary: GAI (and RGA) are the major growth repressors in the GA receptor (gid1) mutant background, demonstrating GAI negatively regulates GA signaling. Core function. Reason: Directly supported core repressor function of GAI in GA signaling. Supporting Evidence: PMID:17416730 GAI and its close homolog REPRESSOR OF ga1-3 are the major growth repressors in a GA receptor mutant background |
| GO:0009739 response to gibberellin | IEP PMID:17333251 Identification of conserved tyrosine residues important for ... | ACCEPT | Summary: GAI is among the DELLA proteins shown to be degradable by GA in BY2 cells (Tyr-phosphorylation-dependent), reflecting that GAI responds to gibberellin. The paper focuses on RGL2 but explicitly includes GAI. Reason: GAI's GA-responsiveness (GA-induced degradation) is directly supported; consistent with the other response-to-gibberellin annotations. Supporting Evidence: PMID:17333251 four DELLA proteins of Arabidopsis, namely GAI, RGL1, RGL2 and RGL3, expressed in tobacco BY2 cells, are degradable by GA |
| GO:0010218 response to far red light | IEP PMID:17449805 PIL5, a phytochrome-interacting bHLH protein, regulates gibb... | KEEP AS NON CORE | Summary: GAI is a direct transcriptional target of the phytochrome-interacting factor PIL5/PIF1; light (via phytochromes) regulates GAI transcript levels. Thus GAI expression responds to light signaling. The annotation reflects GAI as a downstream responder rather than an effector of far-red responses. Reason: Supported as a response-to-light expression-level annotation (GAI is a PIL5 target), but it is a non-core consequence rather than a defining GAI function. Supporting Evidence: PMID:17449805 PIL5 increases the expression of two GA repressor (DELLA) genes, GA-INSENSITIVE (GAI) and REPRESSOR OF GA1-3 (RGA/RGA1), in darkness |
| GO:0006808 regulation of nitrogen utilization | IMP PMID:9237632 Sequence and characterization of two Arabidopsis thaliana cD... | MARK AS OVER ANNOTATED | Summary: GAI (RGA2) was originally isolated by complementation of a yeast gln3 gdh1 nitrogen-regulation mutant. This is a heterologous yeast complementation phenotype; there is no direct evidence GAI regulates nitrogen utilization in planta. Reason: The annotation rests solely on a heterologous yeast complementation cloning assay, not on a demonstrated native function in Arabidopsis nitrogen utilization; GAI is a GA-signaling repressor. Likely over-annotation. Supporting Evidence: PMID:9237632 isolated two Arabidopsis thaliana cDNAs by complementation of a yeast gln3 gdh1 strain that is affected in the regulation of nitrogen metabolism |
| GO:0009740 gibberellic acid mediated signaling pathway | TAS PMID:10421366 'Green revolution' genes encode mutant gibberellin response ... | ACCEPT | Summary: GAI is a GA response modulator (the green revolution gene class); placement in the GA-mediated signaling pathway is well established. Reason: GAI is a core component of the GA-mediated signaling pathway. Supporting Evidence: PMID:10421366 encode mutant gibberellin response modulators |
| GO:0010233 phloem transport | IMP PMID:15773853 Phloem long-distance trafficking of GIBBERELLIC ACID-INSENSI... | KEEP AS NON CORE | Summary: GAI mRNA undergoes selective long-distance phloem trafficking, affecting leaf development at distant sites. This describes movement of the GAI transcript (mRNA as the mobile signal), not a protein function of GAI in mediating phloem transport. Reason: The evidence concerns GAI as a mobile RNA cargo (engineered gain-of-function transcript), a special phenomenon; it is peripheral to and does not represent GAI's core protein function. Supporting Evidence: PMID:15773853 Both engineered mutant gai transcripts were able to exit the scion phloem and traffic cell to cell into the shoot apex |
| GO:0003700 DNA-binding transcription factor activity | TAS PMID:10421366 'Green revolution' genes encode mutant gibberellin response ... | MARK AS OVER ANNOTATED | Summary: This annotation derives from the 1999 inference that GAI orthologues resemble nuclear transcription factors. Subsequent mechanistic work established that DELLA proteins, including GAI, LACK a DNA-binding domain and do not bind DNA sequence-specifically; they regulate transcription via protein-protein interactions (coactivator of GAF1; titration of PIFs/BZR1). Reason: GAI has no DNA-binding domain and is not a classic DNA-binding transcription factor; this term is contradicted by later evidence. The correct MF is transcription coactivator activity (GO:0003713). Proposed replacements: transcription coactivator activity Supporting Evidence: PMID:24989044 DELLAs are nuclear proteins lacking a DNA binding domain PMID:25035403 although DELLAs lack known DNA binding motifs |
| GO:0005634 nucleus | TAS PMID:10421366 'Green revolution' genes encode mutant gibberellin response ... | ACCEPT | Summary: GAI orthologues described as nuclear; concordant with experimentally established nuclear localization. Reason: Nuclear localization is well supported. Supporting Evidence: PMID:12492836 nuclear localisation of GAI |
| GO:0003700 DNA-binding transcription factor activity | ISS PMID:11487693 Expression of Arabidopsis GAI in transgenic rice represses m... | MARK AS OVER ANNOTATED | Summary: Sequence-similarity-based assertion of DNA-binding TF activity. As for the TAS annotation, this is contradicted by evidence that DELLAs lack a DNA-binding domain. Reason: GAI lacks a DNA-binding domain; ISS propagation of DNA-binding TF activity is an over-annotation. The supported MF is coactivator activity. Proposed replacements: transcription coactivator activity Supporting Evidence: PMID:24989044 DELLAs are nuclear proteins lacking a DNA binding domain |
| GO:0003700 DNA-binding transcription factor activity | ISS PMID:11118137 Arabidopsis transcription factors: genome-wide comparative a... | MARK AS OVER ANNOTATED | Summary: Genome-wide TF comparison classified GRAS/GAI as a transcription factor by homology. Not supported as a DNA-binding TF activity for GAI, which lacks a DNA-binding domain. Reason: Bioinformatic TF-family classification does not establish sequence-specific DNA-binding activity; contradicted by mechanistic evidence for DELLAs. Proposed replacements: transcription coactivator activity Supporting Evidence: PMID:25035403 although DELLAs lack known DNA binding motifs |
| GO:0003700 DNA-binding transcription factor activity | ISS PMID:9237632 Sequence and characterization of two Arabidopsis thaliana cD... | MARK AS OVER ANNOTATED | Summary: ISS DNA-binding TF activity propagated from the original RGA2/GAI cloning/sequence paper. Same issue - GAI lacks a DNA-binding domain. Reason: Over-annotation by sequence similarity; GAI is not a DNA-binding transcription factor. Proposed replacements: transcription coactivator activity Supporting Evidence: PMID:24989044 DELLAs are nuclear proteins lacking a DNA binding domain |
| GO:0009938 negative regulation of gibberellic acid mediated signaling pathway | TAS PMID:11925042 Molecular and physiological characterization of arabidopsis ... | ACCEPT | Summary: Characterization of GAI alleles confirming GAI is a growth repressor whose activity is opposed by GA. Core repressive function. Reason: Well-supported core function - GAI negatively regulates GA signaling. Supporting Evidence: PMID:11925042 GAI is a growth repressor whose activity is opposed by GA |
| GO:0005634 nucleus | ISS PMID:10713441 Rice gibberellin-insensitive gene homolog, OsGAI, encodes a ... | ACCEPT | Summary: Nuclear localization inferred from the rice GAI homolog OsGAI (nuclear-localized). Concordant with direct evidence for Arabidopsis GAI. Reason: Nuclear localization of GAI is well supported by direct evidence; the ISS is consistent. Supporting Evidence: PMID:10713441 OsGAI, encodes a nuclear-localized protein |
| GO:0003700 DNA-binding transcription factor activity | IBA GO_REF:0000033 | MARK AS OVER ANNOTATED | Summary: DNA-binding transcription factor activity inherited from the GRAS family root node PTN000780710. Reason: Same claim as this gene's other GO:0003700 rows and given the same action. DELLA proteins have no DNA-binding domain; they regulate transcription as coactivators of DNA-binding factors (IDD/GAF1) and by sequestering others (PIFs). The IBD at the GRAS root generalizes a DNA-binding activity that no DELLA has been shown to have. Propagation Review Root cause: SOURCE BAD Failure modes: ROLE CONFLATION Sources checked: PANTHER:PTN000780710 · PTN000780710 SOURCE BAD 2017 IBD at the root of the whole GRAS family, seeded by RGA, SCR and Medicago RAM1. The PTHR31636 family review rates it WRONG_NODE. DELLAs and SHR-SCR lack a DNA-binding domain and act as cofactors of DNA-binding partners (IDD/GAF1, JKD), so the seeds do not support a DNA-binding transcription factor activity for the ancestral GRAS protein. Proposed replacements: transcription coactivator activity Supporting Evidence: PMID:24989044 DELLAs are nuclear proteins lacking a DNA binding domain PMID:25035403 although DELLAs lack known DNA binding motifs |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: Nuclear localization inherited from the GRAS family root node PTN000780710. Reason: Matches this gene's experimental nuclear rows. The PTHR31636 family review rates this node SOUND, and every reviewed GRAS member accepts nucleus. Supporting Evidence: PMID:12492836 We also show that neither of the two putative nuclear localisation signals contained in DELLA proteins are individually necessary for nuclear localisation of GAI. PMID:23583555 physical interaction between the nuclear-localized DELLA proteins and the prefoldin complex |
| GO:0006355 regulation of DNA-templated transcription | IBA GO_REF:0000033 | ACCEPT | Summary: Regulation of DNA-templated transcription inherited from the GRAS family root node PTN000780710. Reason: Correct when read as transcriptional regulation by any mechanism. DELLAs coactivate GAF1/IDD factors and sequester PIFs, so they regulate transcription without binding DNA themselves. The PTHR31636 family review rates this node SOUND. Supporting Evidence: PMID:25035403 although DELLAs lack known DNA binding motifs |
| GO:0009739 response to gibberellin | IBA GO_REF:0000033 | ACCEPT | Summary: Response to gibberellin inherited from the eurosid GAI/RGA clade node PTN004849723. Reason: Matches this gene's experimental rows for the same term. GA triggers GID1-dependent, SCF(SLY1)-mediated degradation of the DELLA, which is the core of the GA response. The family review rates the node SOUND. Supporting Evidence: PMID:11606552 Removing both RGA and GAI function allows for complete derepression of many aspects of GA signaling. PMID:11606552 the rga-24 and gai-t6 null mutations have a synergistic effect on plant growth |
| GO:0009938 negative regulation of gibberellic acid mediated signaling pathway | IBA GO_REF:0000033 | ACCEPT | Summary: Negative regulation of gibberellin signaling inherited from the GAI/RGA clade node PTN004849723. Reason: Core DELLA function, matching this gene's experimental rows. The family review rates the placement SOUND (if anything conservative). Supporting Evidence: PMID:11606552 RGA and GAI are negative regulators of the gibberellin (GA) signal transduction pathway in Arabidopsis thaliana. file:ARATH/GAI/GAI-deep-research-falcon.md GAI is one of five Arabidopsis DELLA repressors of GA responses |
| GO:1900033 negative regulation of trichome patterning | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: Negative regulation of trichome patterning inherited from the GAI/RGA clade node PTN004849723. Reason: Matches this gene's experimental rows, kept non-core as a pleiotropic developmental output of DELLA-mediated GA repression. Supporting Evidence: PMID:11606552 Phenotypes rescued include abaxial trichome initiation |
| GO:2000033 regulation of seed dormancy process | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: Regulation of seed dormancy inherited from the GAI/RGA clade node PTN004849723. Reason: Matches this gene's other row for the term, kept non-core (redundant DELLA control of dormancy and germination). Supporting Evidence: PMID:24989044 increased GA levels reduce DELLA protein abundance and release ATML1/PDF2 to activate L1 box gene expression, thus enhancing germination potential |
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Download this section (compressed HTML)Q: What is the direct molecular activity by which the GAI GRAS domain effects transcriptional coactivation of GAF1/IDD factors (e.g. recruitment of chromatin modifiers), given that DELLAs lack catalytic motifs?
Suggested experts: Plant transcription/chromatin researchers
Q: To what extent are GAI-specific (versus RGA-redundant) functions attributable to its relative GA-stability and distinct interaction partners?
Suggested experts: Gibberellin signaling researchers
Experiment: Genome-wide DELLA-target mapping (ChIP-seq/CUT&RUN for GAI together with partner TFs) to distinguish direct coactivation targets from titration targets and to confirm GAI is recruited to DNA only via partner TFs.
Experiment: Structure-function dissection of the GAI GRAS subdomains (LRI, VHIID, PFYRE, SAW) to map coactivator versus repressor interaction surfaces.
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