ARR1 (ARABIDOPSIS RESPONSE REGULATOR 1) is a type-B response regulator and the founding member of the subfamily-1 type-B ARR transcription factors that execute cytokinin signaling in Arabidopsis thaliana. It has an N-terminal receiver domain with a conserved phospho-accepting aspartate, a central Myb-related GARP (B-motif) DNA-binding domain that recognizes AGAT(T)-containing cis-elements, and a C-terminal transactivation domain. ARR1 is nuclear-localized independently of its receiver domain; phosphorylation of the receiver domain by AHP histidine phosphotransfer proteins relieves its autoinhibition, and ARR1 directly activates cytokinin primary-response genes, including the type-A ARRs (e.g. ARR6) that provide negative feedback, and developmental targets such as SHY2/IAA3 and WUSCHEL. Acting redundantly with ARR10 and ARR12, ARR1 controls root meristem size, shoot growth, shoot regeneration and stem-cell niche specification, chlorophyll and anthocyanin levels, callus formation, and negatively regulates drought tolerance.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0000156 phosphorelay response regulator activity | ISS PMID:12068096 Two-component signal transduction pathways in Arabidopsis. | ACCEPT | Summary: ARR1 is a type-B response regulator whose N-terminal receiver domain accepts a phosphoryl group on a conserved aspartate from AHP phosphotransfer proteins, activating its C-terminal Myb-related (GARP) DNA-binding/transactivation output. Reason: Phosphorelay response regulator activity is the defining signalling activity of type-B ARRs. Supporting Evidence: PMID:11691951 the phosphorelay to ARR1, probably from CRE1, constitutes an intracellular signal transduction occurring immediately after cytokinin perception PMID:12068096 nuclear AHP translocation enables the activation of B-type ARR proteins, which in turn activate the transcription of A-type ARRs |
| GO:0000160 phosphorelay signal transduction system | IEA GO_REF:0000002 | ACCEPT | Summary: ARR1 is the terminal transcriptional output of the AHK-AHP-ARR multistep phosphorelay. Reason: Core process of type-B ARRs. Supporting Evidence: PMID:18723577 Our results support a model in which cytokinin regulates a wide array of downstream responses through the action of a multistep phosphorelay that culminates in transcriptional regulation by ARR1, ARR10, and ARR12. |
| GO:0000976 transcription cis-regulatory region binding | IPI PMID:31806676 A PXY-Mediated Transcriptional Network Integrates Signaling ... | ACCEPT | Summary: ARR1 bound promoters of vascular regulators in an enhanced yeast one-hybrid network screen. Reason: Consistent with ARR1 being a sequence-specific DNA-binding transcription factor that binds cis-regulatory regions of target genes. The cached full text of PMID:31806676 never mentions ARR1; the ARR1 eY1H promoter hits (with AT1G68810 and AT3G25710) are presumably in supplementary data not available in the cache, so no PMID:31806676 quote is attached and we defer to the curator who read it. Independent support for sequence-specific DNA binding by ARR1 is quoted below. Supporting Evidence: PMID:11135105 Their middle segments, which faintly resemble the mammalian oncogene product Myb, were capable of binding double-stranded DNA in a sequence-specific manner in vitro. |
| GO:0003677 DNA binding | IEA GO_REF:0000002 | MODIFY | Summary: InterPro-based annotation of DNA binding for the Myb-like GARP domain of ARR1. Reason: Correct but general; type-B ARRs bind DNA in a sequence-specific manner (core motif AGATT). Proposed replacements: sequence-specific DNA binding Supporting Evidence: PMID:11135105 Their middle segments, which faintly resemble the mammalian oncogene product Myb, were capable of binding double-stranded DNA in a sequence-specific manner in vitro. |
| GO:0003700 DNA-binding transcription factor activity | IBA GO_REF:0000033 | ACCEPT | Summary: ARR1 is a DNA-binding transcription factor that activates cytokinin primary-response genes such as the type-A ARRs. Reason: Core molecular function of type-B ARRs; DNA binding and transactivation are experimentally demonstrated. Supporting Evidence: PMID:11135105 Both ARR1 and ARR2 promoted expression of a reporter gene in plant cells through their own target sequence. PMID:16227453 These results indicate that there is functional overlap among the type-B ARRs and that they act as positive regulators of cytokinin signal transduction. |
| GO:0003700 DNA-binding transcription factor activity | IDA PMID:11135105 Arabidopsis ARR1 and ARR2 response regulators operate as tra... | ACCEPT | Summary: ARR1 is a DNA-binding transcription factor that activates cytokinin primary-response genes such as the type-A ARRs. Reason: Core molecular function of type-B ARRs; DNA binding and transactivation are experimentally demonstrated. Supporting Evidence: PMID:11135105 Their middle segments, which faintly resemble the mammalian oncogene product Myb, were capable of binding double-stranded DNA in a sequence-specific manner in vitro. PMID:11135105 Both ARR1 and ARR2 promoted expression of a reporter gene in plant cells through their own target sequence. |
| GO:0003700 DNA-binding transcription factor activity | IEA GO_REF:0000002 | ACCEPT | Summary: ARR1 is a DNA-binding transcription factor that activates cytokinin primary-response genes such as the type-A ARRs. Reason: Core molecular function of type-B ARRs; DNA binding and transactivation are experimentally demonstrated. Supporting Evidence: PMID:11135105 Both ARR1 and ARR2 promoted expression of a reporter gene in plant cells through their own target sequence. PMID:16227453 These results indicate that there is functional overlap among the type-B ARRs and that they act as positive regulators of cytokinin signal transduction. |
| GO:0003700 DNA-binding transcription factor activity | ISS PMID:11118137 Arabidopsis transcription factors: genome-wide comparative a... | ACCEPT | Summary: ARR1 is a DNA-binding transcription factor that activates cytokinin primary-response genes such as the type-A ARRs. Reason: Core molecular function of type-B ARRs; DNA binding and transactivation are experimentally demonstrated. PMID:11118137 is a genome-wide transcription factor catalogue whose cached abstract does not mention ARR1, so the experimental ARR1 evidence is quoted instead. Supporting Evidence: PMID:11135105 Both ARR1 and ARR2 promoted expression of a reporter gene in plant cells through their own target sequence. |
| GO:0005515 protein binding | IPI PMID:15714319 In vitro recombination cloning of entire cDNA libraries in A... | REMOVE | Summary: Interaction of ARR1 with the histidine phosphotransfer protein AHP3. Reason: Generic protein binding is uninformative. The AHP-ARR interaction is the docking step for phosphotransfer to the receiver domain, already captured by phosphorelay response regulator activity (GO:0000156). Removal does not imply the interaction is false. Supporting Evidence: PMID:15714319 The functionality of the in vitro recombination system for the shuttling of entire libraries was then further tested by protein-protein interaction screens. |
| GO:0005515 protein binding | IPI PMID:15714319 In vitro recombination cloning of entire cDNA libraries in A... | REMOVE | Summary: Interaction of ARR1 with the histidine phosphotransfer protein AHP1. Reason: Generic protein binding is uninformative. The AHP-ARR interaction is the docking step for phosphotransfer to the receiver domain, already captured by phosphorelay response regulator activity (GO:0000156). Removal does not imply the interaction is false. Supporting Evidence: PMID:15714319 The functionality of the in vitro recombination system for the shuttling of entire libraries was then further tested by protein-protein interaction screens. |
| GO:0005515 protein binding | IPI PMID:16965536 Analysis of protein interactions within the cytokinin-signal... | REMOVE | Summary: Interaction of ARR1 with the histidine phosphotransfer protein AHP3. Reason: Generic protein binding is uninformative. The AHP-ARR interaction is the docking step for phosphotransfer to the receiver domain, already captured by phosphorelay response regulator activity (GO:0000156). Removal does not imply the interaction is false. Supporting Evidence: PMID:16965536 An interaction map of this signaling pathway shows the Arabidopsis histidine phosphotransfer proteins as hubs, which interact with members from all other protein families, mostly in a redundant fashion. |
| GO:0005515 protein binding | IPI PMID:16965536 Analysis of protein interactions within the cytokinin-signal... | REMOVE | Summary: Interaction of ARR1 with the histidine phosphotransfer protein AHP1. Reason: Generic protein binding is uninformative. The AHP-ARR interaction is the docking step for phosphotransfer to the receiver domain, already captured by phosphorelay response regulator activity (GO:0000156). Removal does not imply the interaction is false. Supporting Evidence: PMID:16965536 An interaction map of this signaling pathway shows the Arabidopsis histidine phosphotransfer proteins as hubs, which interact with members from all other protein families, mostly in a redundant fashion. |
| GO:0005515 protein binding | IPI PMID:18642946 Toward an interaction map of the two-component signaling pat... | REMOVE | Summary: Interaction of ARR1 with the histidine phosphotransfer protein AHP3. Reason: Generic protein binding is uninformative. The AHP-ARR interaction is the docking step for phosphotransfer to the receiver domain, already captured by phosphorelay response regulator activity (GO:0000156). Removal does not imply the interaction is false. Supporting Evidence: PMID:18642946 we conducted medium-scale yeast two-hybrid screens focusing on those members of the TCS, which are thought to be involved in cytokinin signaling |
| GO:0005515 protein binding | IPI PMID:18642946 Toward an interaction map of the two-component signaling pat... | REMOVE | Summary: Interaction of ARR1 with the histidine phosphotransfer protein AHP1. Reason: Generic protein binding is uninformative. The AHP-ARR interaction is the docking step for phosphotransfer to the receiver domain, already captured by phosphorelay response regulator activity (GO:0000156). Removal does not imply the interaction is false. Supporting Evidence: PMID:18642946 we conducted medium-scale yeast two-hybrid screens focusing on those members of the TCS, which are thought to be involved in cytokinin signaling |
| GO:0005634 nucleus | IBA GO_REF:0000033 | ACCEPT | Summary: ARR1 is a nuclear transcription factor. Reason: Nuclear localization of type-B ARRs is experimentally established. Supporting Evidence: PMID:11135105 ARR1 and ARR2 were localized in the nuclei of plant cells regardless of the presence or absence of their signal receiver domain. |
| GO:0005634 nucleus | IDA PMID:11135105 Arabidopsis ARR1 and ARR2 response regulators operate as tra... | ACCEPT | Summary: ARR1 is a nuclear transcription factor. Reason: Nuclear localization of type-B ARRs is experimentally established. Supporting Evidence: PMID:11135105 ARR1 and ARR2 were localized in the nuclei of plant cells regardless of the presence or absence of their signal receiver domain. |
| GO:0005634 nucleus | IEA GO_REF:0000044 | ACCEPT | Summary: ARR1 is a nuclear transcription factor. Reason: Nuclear localization of type-B ARRs is experimentally established. Supporting Evidence: PMID:11135105 ARR1 and ARR2 were localized in the nuclei of plant cells regardless of the presence or absence of their signal receiver domain. |
| GO:0005737 cytoplasm | ISM GO_REF:0000122 | REMOVE | Summary: Sequence-model (ISM) subcellular prediction. Reason: ARR1 is a nuclear transcription factor; nuclear localization is independent of its receiver domain and there is no evidence for a functional cytoplasmic or plastid pool. Supporting Evidence: PMID:11135105 ARR1 and ARR2 were localized in the nuclei of plant cells regardless of the presence or absence of their signal receiver domain. |
| GO:0005829 cytosol | HDA PMID:28887381 Global Analysis of Membrane-associated Protein Oligomerizati... | MARK AS OVER ANNOTATED | Summary: High-throughput proteomic detection of ARR1 in a cytosolic fraction. Reason: ARR1 localizes to the nucleus regardless of its receiver domain; detection in a soluble fraction in a membrane-proteomics study is likely due to nuclear leakage during fractionation rather than a functional cytosolic pool. Supporting Evidence: PMID:11135105 ARR1 and ARR2 were localized in the nuclei of plant cells regardless of the presence or absence of their signal receiver domain. PMID:28887381 Over 150 proteins had a complicated localization pattern, and were clearly partitioned between cytosolic and membrane-associated pools. |
| GO:0006355 regulation of DNA-templated transcription | IBA GO_REF:0000033 | ACCEPT | Summary: ARR1 regulates (activates) transcription of cytokinin-responsive genes. Reason: Core process of a DNA-binding transcription factor. Supporting Evidence: PMID:11691951 the transcription factor-type response regulator ARR1 directs transcriptional activation of the ARR6 gene, which responds to cytokinins without de novo protein synthesis |
| GO:0009414 response to water deprivation | IEP PMID:26884175 Arabidopsis type B cytokinin response regulators ARR1, ARR10... | KEEP AS NON CORE | Summary: ARR1 contributes to 'response to water deprivation' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:26884175 Further drought-tolerance tests of lower-order double and single mutants indicated that ARR1, ARR10, and ARR12 negatively and redundantly control plant responses to drought, with ARR1 appearing to bear the most critical function among the three proteins. PMID:26884175 Expression of all three ARR genes was repressed by dehydration and ABA treatments |
| GO:0009414 response to water deprivation | IGI PMID:26884175 Arabidopsis type B cytokinin response regulators ARR1, ARR10... | KEEP AS NON CORE | Summary: ARR1 contributes to 'response to water deprivation' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:26884175 Further drought-tolerance tests of lower-order double and single mutants indicated that ARR1, ARR10, and ARR12 negatively and redundantly control plant responses to drought, with ARR1 appearing to bear the most critical function among the three proteins. PMID:26884175 Expression of all three ARR genes was repressed by dehydration and ABA treatments |
| GO:0009414 response to water deprivation | IGI PMID:26884175 Arabidopsis type B cytokinin response regulators ARR1, ARR10... | KEEP AS NON CORE | Summary: ARR1 contributes to 'response to water deprivation' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:26884175 Further drought-tolerance tests of lower-order double and single mutants indicated that ARR1, ARR10, and ARR12 negatively and redundantly control plant responses to drought, with ARR1 appearing to bear the most critical function among the three proteins. PMID:26884175 Expression of all three ARR genes was repressed by dehydration and ABA treatments |
| GO:0009414 response to water deprivation | IMP PMID:26884175 Arabidopsis type B cytokinin response regulators ARR1, ARR10... | KEEP AS NON CORE | Summary: ARR1 contributes to 'response to water deprivation' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:26884175 Further drought-tolerance tests of lower-order double and single mutants indicated that ARR1, ARR10, and ARR12 negatively and redundantly control plant responses to drought, with ARR1 appearing to bear the most critical function among the three proteins. PMID:26884175 Expression of all three ARR genes was repressed by dehydration and ABA treatments |
| GO:0009507 chloroplast | ISM GO_REF:0000122 | REMOVE | Summary: Sequence-model (ISM) subcellular prediction. Reason: ARR1 is a nuclear transcription factor; nuclear localization is independent of its receiver domain and there is no evidence for a functional cytoplasmic or plastid pool. Supporting Evidence: PMID:11135105 ARR1 and ARR2 were localized in the nuclei of plant cells regardless of the presence or absence of their signal receiver domain. |
| GO:0009735 response to cytokinin | IGI PMID:16227453 Multiple type-B response regulators mediate cytokinin signal... | ACCEPT | Summary: ARR1 is one of the principal type-B ARRs (with ARR10 and ARR12/ARR1) mediating transcriptional responses to cytokinin; higher-order type-B arr mutants are almost completely cytokinin-insensitive. Reason: Core process; extensive genetic evidence from single and higher-order mutants. Supporting Evidence: PMID:16227453 These results indicate that there is functional overlap among the type-B ARRs and that they act as positive regulators of cytokinin signal transduction. PMID:16227453 The triple mutant arr1,10,12 showed almost complete insensitivity to cytokinin under many of the assay conditions used. |
| GO:0009735 response to cytokinin | IGI PMID:16227453 Multiple type-B response regulators mediate cytokinin signal... | ACCEPT | Summary: ARR1 is one of the principal type-B ARRs (with ARR10 and ARR12/ARR1) mediating transcriptional responses to cytokinin; higher-order type-B arr mutants are almost completely cytokinin-insensitive. Reason: Core process; extensive genetic evidence from single and higher-order mutants. Supporting Evidence: PMID:16227453 These results indicate that there is functional overlap among the type-B ARRs and that they act as positive regulators of cytokinin signal transduction. PMID:16227453 The triple mutant arr1,10,12 showed almost complete insensitivity to cytokinin under many of the assay conditions used. |
| GO:0009735 response to cytokinin | IGI PMID:18723577 Type B response regulators of Arabidopsis play key roles in ... | ACCEPT | Summary: ARR1 is one of the principal type-B ARRs (with ARR10 and ARR12/ARR1) mediating transcriptional responses to cytokinin; higher-order type-B arr mutants are almost completely cytokinin-insensitive. Reason: Core process; extensive genetic evidence from single and higher-order mutants. Supporting Evidence: PMID:18723577 Our results support a model in which cytokinin regulates a wide array of downstream responses through the action of a multistep phosphorelay that culminates in transcriptional regulation by ARR1, ARR10, and ARR12. |
| GO:0009735 response to cytokinin | IMP PMID:18502977 The transcriptional repressor ARR1-SRDX suppresses pleiotrop... | ACCEPT | Summary: ARR1 is one of the principal type-B ARRs (with ARR10 and ARR12/ARR1) mediating transcriptional responses to cytokinin; higher-order type-B arr mutants are almost completely cytokinin-insensitive. Reason: Core process; extensive genetic evidence from single and higher-order mutants. Supporting Evidence: PMID:18502977 In a protoplast test system, ARR1-SRDX suppressed ARR6:beta-glucuronidase reporter gene activation by different B-type ARRs. |
| GO:0009736 cytokinin-activated signaling pathway | IBA GO_REF:0000033 | ACCEPT | Summary: ARR1 is one of the principal type-B ARRs (with ARR10 and ARR12/ARR1) mediating transcriptional responses to cytokinin; higher-order type-B arr mutants are almost completely cytokinin-insensitive. Reason: Core process; extensive genetic evidence from single and higher-order mutants. Supporting Evidence: PMID:18723577 Our results support a model in which cytokinin regulates a wide array of downstream responses through the action of a multistep phosphorelay that culminates in transcriptional regulation by ARR1, ARR10, and ARR12. PMID:16227453 These results indicate that there is functional overlap among the type-B ARRs and that they act as positive regulators of cytokinin signal transduction. |
| GO:0009736 cytokinin-activated signaling pathway | IEA GO_REF:0000120 | ACCEPT | Summary: ARR1 is one of the principal type-B ARRs (with ARR10 and ARR12/ARR1) mediating transcriptional responses to cytokinin; higher-order type-B arr mutants are almost completely cytokinin-insensitive. Reason: Core process; extensive genetic evidence from single and higher-order mutants. Supporting Evidence: PMID:18723577 Our results support a model in which cytokinin regulates a wide array of downstream responses through the action of a multistep phosphorelay that culminates in transcriptional regulation by ARR1, ARR10, and ARR12. PMID:16227453 These results indicate that there is functional overlap among the type-B ARRs and that they act as positive regulators of cytokinin signal transduction. |
| GO:0009736 cytokinin-activated signaling pathway | IGI PMID:18723577 Type B response regulators of Arabidopsis play key roles in ... | ACCEPT | Summary: ARR1 is one of the principal type-B ARRs (with ARR10 and ARR12/ARR1) mediating transcriptional responses to cytokinin; higher-order type-B arr mutants are almost completely cytokinin-insensitive. Reason: Core process; extensive genetic evidence from single and higher-order mutants. Supporting Evidence: PMID:18723577 Our results support a model in which cytokinin regulates a wide array of downstream responses through the action of a multistep phosphorelay that culminates in transcriptional regulation by ARR1, ARR10, and ARR12. |
| GO:0009736 cytokinin-activated signaling pathway | TAS PMID:12068096 Two-component signal transduction pathways in Arabidopsis. | ACCEPT | Summary: ARR1 is one of the principal type-B ARRs (with ARR10 and ARR12/ARR1) mediating transcriptional responses to cytokinin; higher-order type-B arr mutants are almost completely cytokinin-insensitive. Reason: Core process; extensive genetic evidence from single and higher-order mutants. Supporting Evidence: PMID:12068096 A multistep two-component phosphorelay system with distinct AHK, AHP, and ARR proteins plays a central role in cytokinin signal transduction |
| GO:0010082 regulation of root meristem growth | IMP PMID:23482873 Functional characterization of type-B response regulators in... | KEEP AS NON CORE | Summary: ARR1 contributes to 'regulation of root meristem growth' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:23482873 Cytokinin responses are predominantly mediated by subfamily 1 members, with cytokinin-mediated effects on root growth and root meristem size correlating with type-B ARR expression levels. PMID:17363254 cytokinins control the rate of meristematic cell differentiation and thus determine root-meristem size via a two-component receptor histidine kinase-transcription factor signaling pathway |
| GO:0010082 regulation of root meristem growth | IMP PMID:23482873 Functional characterization of type-B response regulators in... | KEEP AS NON CORE | Summary: ARR1 contributes to 'regulation of root meristem growth' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:23482873 Cytokinin responses are predominantly mediated by subfamily 1 members, with cytokinin-mediated effects on root growth and root meristem size correlating with type-B ARR expression levels. PMID:17363254 cytokinins control the rate of meristematic cell differentiation and thus determine root-meristem size via a two-component receptor histidine kinase-transcription factor signaling pathway |
| GO:0010380 regulation of chlorophyll biosynthetic process | IGI PMID:18723577 Type B response regulators of Arabidopsis play key roles in ... | KEEP AS NON CORE | Summary: ARR1 contributes to 'regulation of chlorophyll biosynthetic process' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:18723577 The triple mutant exhibited reduced stature due to decreased cell division in the shoot, enhanced seed size, increased sensitivity to light, altered chlorophyll and anthocyanin concentrations, and an aborted primary root with protoxylem but no metaxylem. |
| GO:0010492 maintenance of shoot apical meristem identity | IGI PMID:28576846 Type-B ARABIDOPSIS RESPONSE REGULATORs Specify the Shoot Ste... | KEEP AS NON CORE | Summary: ARR1 contributes to 'maintenance of shoot apical meristem identity' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:28576846 Here, we show that type-B ARABIDOPSIS RESPONSE REGULATORs (ARRs), critical components of cytokinin signaling, activate the transcription of WUSCHEL (WUS), which encodes a key regulator for maintaining stem cells. |
| GO:0031537 regulation of anthocyanin metabolic process | IGI PMID:18723577 Type B response regulators of Arabidopsis play key roles in ... | KEEP AS NON CORE | Summary: ARR1 contributes to 'regulation of anthocyanin metabolic process' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:18723577 The triple mutant exhibited reduced stature due to decreased cell division in the shoot, enhanced seed size, increased sensitivity to light, altered chlorophyll and anthocyanin concentrations, and an aborted primary root with protoxylem but no metaxylem. |
| GO:0043565 sequence-specific DNA binding | IBA GO_REF:0000033 | ACCEPT | Summary: ARR1 binds specific promoter motifs through its Myb-related B-motif (GARP) domain. Reason: Sequence-specific DNA binding by type-B ARRs is experimentally established for ARR1/ARR2 and ARR12. Supporting Evidence: PMID:11135105 Their middle segments, which faintly resemble the mammalian oncogene product Myb, were capable of binding double-stranded DNA in a sequence-specific manner in vitro. |
| GO:0048364 root development | IMP PMID:23482873 Functional characterization of type-B response regulators in... | KEEP AS NON CORE | Summary: ARR1 contributes to 'root development' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:23482873 Cytokinin responses are predominantly mediated by subfamily 1 members, with cytokinin-mediated effects on root growth and root meristem size correlating with type-B ARR expression levels. |
| GO:0048367 shoot system development | IGI PMID:18723577 Type B response regulators of Arabidopsis play key roles in ... | KEEP AS NON CORE | Summary: ARR1 contributes to 'shoot system development' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:18723577 The triple mutant exhibited reduced stature due to decreased cell division in the shoot, enhanced seed size, increased sensitivity to light, altered chlorophyll and anthocyanin concentrations, and an aborted primary root with protoxylem but no metaxylem. |
| GO:0071368 cellular response to cytokinin stimulus | IMP PMID:23482873 Functional characterization of type-B response regulators in... | ACCEPT | Summary: ARR1 is one of the principal type-B ARRs (with ARR10 and ARR12/ARR1) mediating transcriptional responses to cytokinin; higher-order type-B arr mutants are almost completely cytokinin-insensitive. Reason: Core process; extensive genetic evidence from single and higher-order mutants. Supporting Evidence: PMID:23482873 Cytokinin responses are predominantly mediated by subfamily 1 members, with cytokinin-mediated effects on root growth and root meristem size correlating with type-B ARR expression levels. PMID:23482873 ARR1, as well as a subset of other subfamily 1 type-B ARRs, restore the cytokinin sensitivity to arr1 arr12. |
| GO:0080022 primary root development | IGI PMID:18723577 Type B response regulators of Arabidopsis play key roles in ... | KEEP AS NON CORE | Summary: ARR1 contributes to 'primary root development' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:18723577 The triple mutant exhibited reduced stature due to decreased cell division in the shoot, enhanced seed size, increased sensitivity to light, altered chlorophyll and anthocyanin concentrations, and an aborted primary root with protoxylem but no metaxylem. |
| GO:0080036 regulation of cytokinin-activated signaling pathway | IMP PMID:23482873 Functional characterization of type-B response regulators in... | MODIFY | Summary: ARR1 is required for normal cytokinin responsiveness in roots. Reason: ARR1 is an integral component of the cytokinin-activated signaling pathway (its terminal transcription factor), not a separate regulator of it; the pathway term is more accurate. Proposed replacements: cytokinin-activated signaling pathway Supporting Evidence: PMID:23482873 Cytokinin responses are predominantly mediated by subfamily 1 members, with cytokinin-mediated effects on root growth and root meristem size correlating with type-B ARR expression levels. PMID:23482873 ARR1, as well as a subset of other subfamily 1 type-B ARRs, restore the cytokinin sensitivity to arr1 arr12. |
| GO:0080113 regulation of seed growth | IMP PMID:23482873 Functional characterization of type-B response regulators in... | KEEP AS NON CORE | Summary: ARR1 contributes to 'regulation of seed growth' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:18723577 The triple mutant exhibited reduced stature due to decreased cell division in the shoot, enhanced seed size, increased sensitivity to light, altered chlorophyll and anthocyanin concentrations, and an aborted primary root with protoxylem but no metaxylem. |
| GO:0090506 axillary shoot meristem initiation | IMP PMID:28389585 A Two-Step Model for de Novo Activation of WUSCHEL during Pl... | KEEP AS NON CORE | Summary: ARR1 contributes to 'axillary shoot meristem initiation' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:28389585 In Arabidopsis, four B-type ARR transcription factors, ARR1, ARR2, ARR10, and ARR12, play essential roles in shoot regeneration. |
| GO:1990110 callus formation | IGI PMID:28904073 Wounding Triggers Callus Formation via Dynamic Hormonal and ... | KEEP AS NON CORE | Summary: ARR1 contributes to 'callus formation' as a downstream output of type-B ARR-mediated cytokinin transcriptional signaling. Reason: Supported by mutant/genetic interaction data, often in redundant higher-order arr mutants; this is a pleiotropic developmental/physiological output rather than the core molecular role. Supporting Evidence: PMID:28904073 We further demonstrate that type-B ARABIDOPSIS RESPONSE REGULATOR-mediated cytokinin signaling regulates the expression of CYCLIN D3;1 (CYCD3;1) |
| GO:0001216 DNA-binding transcription activator activity | IDA PMID:11135105 Arabidopsis ARR1 and ARR2 response regulators operate as tra... | NEW | Summary: ARR1 activates transcription of target genes through its C-terminal transactivation domain after binding promoter motifs. Reason: Existing annotations use the parent DNA-binding transcription factor activity; the experimental data show that the activity is transcriptional activation, so the more specific child term is warranted. Supporting Evidence: PMID:11135105 Both ARR1 and ARR2 promoted expression of a reporter gene in plant cells through their own target sequence. PMID:11691951 the transcription factor-type response regulator ARR1 directs transcriptional activation of the ARR6 gene, which responds to cytokinins without de novo protein synthesis |
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Download this section (compressed HTML)Q: Which target genes are bound by ARR1 versus ARR12 in different tissues, and does ARR12 contribute distinct targets or only dosage to the subfamily-1 type-B ARR output?
Q: How does receiver-domain phosphorylation relieve autoinhibition of type-B ARR DNA binding or transactivation at the structural level?
Experiment: Perform cytokinin-time-course ChIP-seq/DAP-seq for tagged ARR1 and ARR12 expressed from native promoters in the arr1 arr12 background, and compare binding sites and target gene sets.
Hypothesis: ARR1 and ARR12 share most cytokinin-induced binding sites but differ in tissue-specific targets.
Type: ChIP-seq
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