HY5

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0010017 red or far-red light signaling pathway	IBA GO_REF:0000033	ACCEPT	Summary: Red and far-red light signaling pathway is a core function of HY5 as a central integrator of phytochrome-mediated light responses. HY5 directly regulates target genes in response to phytochrome activation and acts downstream of both phyA and phyB signaling. Reason: This is a well-established core function of HY5. Extensive experimental evidence shows HY5 is required for normal responses to red and far-red light, and it acts as a key downstream transcriptional regulator in phytochrome signaling pathways. The IBA evidence code indicates this annotation is based on phylogenetic analysis, which is appropriate for this conserved function. Supporting Evidence: PMID:10990463 HY5 is a bZIP transcription factor that promotes photomorphogenesis... Previous studies suggested that COP1, a negative regulator of photomorphogenesis, directly interacts with nuclear HY5 and targets it for proteasome-mediated degradation. Light negatively regulates the nuclear level of COP1 and thus permits HY5 accumulation file:ARATH/HY5/HY5-deep-research-perplexity-lite.md See deep research file for comprehensive analysis
GO:0010099 regulation of photomorphogenesis	IBA GO_REF:0000033	ACCEPT	Summary: Regulation of photomorphogenesis is the primary and most central function of HY5. It acts as a master transcriptional regulator that promotes the switch from skotomorphogenesis to photomorphogenesis in response to light. Reason: This is the quintessential function of HY5 and represents its core biological role. HY5 is one of the most well-characterized positive regulators of photomorphogenesis in plants. The hy5 mutant exhibits a classic elongated hypocotyl phenotype due to failure to properly regulate photomorphogenic development. This annotation captures HY5s primary biological function and is strongly supported by decades of research. Supporting Evidence: PMID:10990463 HY5 is a bZIP transcription factor that promotes photomorphogenesis file:ARATH/HY5/HY5-deep-research-falcon.md Mechanistically, HY5 functions as a positive regulator of photomorphogenesis (de-etiolation) downstream of multiple photoreceptors, with loss-of-function hy5 mutants displaying long hypocotyl phenotypes under diverse light conditions.
GO:0010114 response to red light	IBA GO_REF:0000033	ACCEPT	Summary: Response to red light is a core function of HY5 as part of its role in integrating phytochrome-mediated light signaling. HY5 is required for normal physiological and developmental responses to red light. Reason: This annotation correctly captures HY5s role in red light responses. While related to the broader red/far-red light signaling pathway annotation, this focuses specifically on the response aspect. HY5 is well-documented to be involved in red light responses through phytochrome signaling pathways. Supporting Evidence: file:ARATH/HY5/HY5-falcon-research.md HY5 acts downstream of the light receptor network—including phytochromes, cryptochromes, and other photoreceptors—thereby transducing light signals
GO:0010218 response to far red light	IBA GO_REF:0000033	ACCEPT	Summary: Response to far red light is a core function of HY5, particularly in mediating phyA-dependent far-red light responses. HY5 is essential for proper far-red light perception and downstream signaling responses. Reason: This annotation correctly represents HY5s role in far-red light responses. Far-red light responses are mediated primarily through phyA signaling, and HY5 acts as a key downstream transcriptional regulator in this pathway. This is a well-established function supported by extensive genetic and molecular evidence. Supporting Evidence: file:ARATH/HY5/HY5-falcon-research.md HY5 acts downstream of the light receptor network—including phytochromes, cryptochromes, and other photoreceptors—thereby transducing light signals
GO:0005634 nucleus	IBA GO_REF:0000033	ACCEPT	Summary: Nuclear localization is essential for HY5 function as a transcription factor. HY5 localizes predominantly to the nucleus where it binds to target gene promoters and regulates transcription. Reason: This annotation is accurate and well-supported. As a transcription factor, HY5 must be nuclear to access its target genes. Multiple experimental studies have confirmed HY5s nuclear localization, and this is consistent with its role in directly binding to DNA and regulating gene expression. Supporting Evidence: PMID:26474641 The in vitro and in vivo molecular interaction studies show that SHW1 physically interacts with both COP1 and HY5... SHW1 promotes COP1-mediated degradation of HY5 through enhanced ubiquitylation in the darkness file:ARATH/HY5/HY5-deep-research-falcon.md HY5 acts primarily in the nucleus. In a key Plant Cell study, GFP–HY5 fluorescence localized exclusively to nuclei across cell types (cotyledons, hypocotyl, roots), and its nuclear localization was reported as not being strongly light regulated.
GO:0000981 DNA-binding transcription factor activity, RNA polymerase II-specific	IEA GO_REF:0000002	ACCEPT	Summary: This annotation correctly captures HY5s core molecular function as a DNA-binding transcription factor that regulates RNA polymerase II-dependent gene expression. HY5 directly binds to specific DNA sequences in target gene promoters. Reason: This annotation accurately represents HY5s primary molecular function. HY5 is a well-characterized transcription factor that binds to G-box and other cis-regulatory elements and regulates transcription by RNA polymerase II. This is supported by extensive ChIP-seq and biochemical studies demonstrating direct DNA binding and transcriptional activation. Supporting Evidence: PMID:17001643 Intrinsically unstructured N-terminal domain of bZIP transcription factor HY5 file:ARATH/HY5/HY5-deep-research-falcon.md HY5 is a sequence-specific DNA-binding transcription factor of the bZIP family. It directly binds light-responsive promoter elements—classically ACGT-centered G-box/light-responsive elements (LREs)—to activate light-induced gene expression programs.
GO:0003677 DNA binding	IEA GO_REF:0000043	MODIFY	Summary: DNA binding is a fundamental molecular function of HY5 as a bZIP transcription factor. HY5 directly binds to DNA through its basic region and leucine zipper domain. Reason: While DNA binding is accurate, this is too general compared to the more specific "DNA-binding transcription factor activity, RNA polymerase II-specific" annotation. The more specific term better captures HY5s function and should be preferred to avoid redundant generic annotations. Proposed replacements: DNA-binding transcription factor activity, RNA polymerase II-specific Supporting Evidence: file:ARATH/HY5/HY5-deep-research-falcon.md HY5 is a sequence-specific DNA-binding transcription factor of the bZIP family. It directly binds light-responsive promoter elements—classically ACGT-centered G-box/light-responsive elements (LREs)—to activate light-induced gene expression programs.
GO:0003700 DNA-binding transcription factor activity	IEA GO_REF:0000002	ACCEPT	Summary: This general transcription factor activity annotation is accurate and represents HY5s core molecular function. Reason: This annotation correctly represents HY5s primary molecular function as a DNA-binding transcription factor. While the more specific GO:0000981 term provides additional precision about RNA polymerase II specificity, this general term is still accurate and appropriate. Multiple evidence types for this core function are acceptable. Supporting Evidence: file:ARATH/HY5/HY5-deep-research-falcon.md HY5 is a sequence-specific DNA-binding transcription factor of the bZIP family. It directly binds light-responsive promoter elements—classically ACGT-centered G-box/light-responsive elements (LREs)—to activate light-induced gene expression programs.
GO:0005634 nucleus	IEA GO_REF:0000044	ACCEPT	Summary: This is a duplicate nuclear localization annotation with IEA evidence, while there is already an IBA annotation for the same term. Reason: Nuclear localization is accurate and well-supported. While this duplicates the IBA annotation, having multiple evidence codes for the same well-established annotation is acceptable, especially when they come from different computational prediction methods (IEA vs IBA).
GO:0006355 regulation of DNA-templated transcription	IEA GO_REF:0000002	ACCEPT	Summary: Regulation of DNA-templated transcription accurately captures HY5s biological function as a transcriptional regulator, though it is very general. Reason: This annotation correctly describes HY5s role in regulating transcription. While general, it accurately captures the biological process in which HY5 participates. This term is appropriately broad and complements the more specific molecular function annotations.
GO:0009585 red, far-red light phototransduction	IEA GO_REF:0000043	REMOVE	Summary: Red, far-red light phototransduction describes the process of converting light signals into cellular responses. HY5 acts downstream in this pathway as a transcriptional effector rather than in the initial signal transduction steps. Reason: "Phototransduction" refers to the initial conversion of light signals to cellular signals by photoreceptors (e.g. phytochromes). HY5 acts strictly downstream as a nuclear transcriptional regulator, not in the signal transduction step itself. The falcon report confirms HY5 functions as a positive regulator of photomorphogenesis downstream of multiple photoreceptors. The accurate, more informative terms ("red or far-red light signaling pathway", "response to red light", "response to far red light") are already present as separate annotations, so this term is both inaccurate for HY5s mechanistic role and redundant; it should be removed rather than retained. Supporting Evidence: file:ARATH/HY5/HY5-deep-research-falcon.md Mechanistically, HY5 functions as a positive regulator of photomorphogenesis (de-etiolation) downstream of multiple photoreceptors, with loss-of-function hy5 mutants displaying long hypocotyl phenotypes under diverse light conditions.
GO:0009738 abscisic acid-activated signaling pathway	IEA GO_REF:0000043	KEEP AS NON CORE	Summary: HY5 has documented involvement in ABA signaling pathways, integrating light and hormone responses. However, this represents a secondary rather than core function. Reason: HY5 does interact with ABA signaling pathways, as evidenced by studies showing altered ABA responsiveness in hy5 mutants. However, this is a secondary function compared to its primary role in light signaling and photomorphogenesis. HY5 integrates multiple signaling pathways including hormonal responses, but ABA signaling is not its primary function. Supporting Evidence: PMID:26474641 This study further reveals that the altered abscisic acid responsiveness of hy5 mutants is modulated by additional loss of SHW1 function
GO:0010017 red or far-red light signaling pathway	IEA GO_REF:0000043	ACCEPT	Summary: This is a duplicate of the IBA annotation for the same GO term. Both annotations correctly identify HY5s core role in red/far-red light signaling. Reason: This annotation is accurate and represents a core function of HY5. While it duplicates the IBA annotation, having multiple evidence codes for such a well-established core function is acceptable and provides additional computational support for the annotation.
GO:0045944 positive regulation of transcription by RNA polymerase II	IEA GO_REF:0000002	ACCEPT	Summary: Positive regulation of transcription by RNA polymerase II accurately describes HY5s primary mode of action as a transcriptional activator of light-responsive genes. Reason: This annotation correctly captures HY5s biological function. HY5 primarily acts as a transcriptional activator, promoting the expression of target genes involved in photomorphogenesis, light responses, and chloroplast development. This is a well-established function supported by extensive experimental evidence. Supporting Evidence: file:ARATH/HY5/HY5-deep-research-falcon.md HY5 is a sequence-specific DNA-binding transcription factor of the bZIP family. It directly binds light-responsive promoter elements—classically ACGT-centered G-box/light-responsive elements (LREs)—to activate light-induced gene expression programs.
GO:0005515 protein binding	IPI PMID:10990463 HY5 stability and activity in arabidopsis is regulated by ph...	MODIFY	Summary: Protein binding annotation supported by experimental evidence of the HY5-COP1 interaction within the COP1 binding domain of HY5. The interaction partner (the COP1 E3 ubiquitin ligase) is defined, so an informative MF term is preferable to generic "protein binding". Reason: Generic "protein binding" is uninformative per GO annotation guidelines. The evidence here is the direct HY5-COP1 interaction (COP1 is an E3 ubiquitin ligase that targets nuclear HY5 for proteasome-mediated degradation), so the informative replacement is "ubiquitin protein ligase binding" (GO:0031625) rather than a DNA-binding term, which would not reflect this protein-protein interaction. Proposed replacements: ubiquitin protein ligase binding Supporting Evidence: PMID:10990463 Previous studies suggested that COP1, a negative regulator of photomorphogenesis, directly interacts with nuclear HY5 and targets it for proteasome-mediated degradation file:ARATH/HY5/HY5-deep-research-falcon.md In darkness, the E3 ubiquitin-ligase-associated factor COP1 accumulates in the nucleus and promotes proteasome-dependent HY5 turnover, repressing photomorphogenesis.
GO:0005515 protein binding	IPI PMID:11226162 Identification of a structural motif that confers specific i...	MODIFY	Summary: This protein binding annotation derives from mapping the structural motif in HY5 that binds the WD40 repeat domain of the COP1 E3 ubiquitin ligase. The specific interacting partner (the COP1 E3 ligase) is known, so an informative MF term is preferable to generic "protein binding". Reason: Generic "protein binding" is uninformative per GO guidelines. Here the interaction partner is defined - HY5 binds the WD40 domain of COP1, an E3 ubiquitin ligase that targets HY5 for proteasomal degradation. The informative replacement is "ubiquitin protein ligase binding" (GO:0031625), which captures the functional nature of the COP1-HY5 interaction underlying light-regulated HY5 stability. Proposed replacements: ubiquitin protein ligase binding Supporting Evidence: PMID:11226162 Identification of a structural motif that confers specific interaction with the WD40 repeat domain of Arabidopsis COP1. file:ARATH/HY5/HY5-deep-research-falcon.md A detailed mechanistic advance defined how COP1 recognizes HY5: COP1’s WD40 repeat domain binds a conserved motif in HY5-interacting partners, with a core V-P-E/D-f-G (f = hydrophobic residue) plus upstream acidic residues.
GO:0005515 protein binding	IPI PMID:17965270 SALT TOLERANCE HOMOLOG2, a B-box protein in Arabidopsis that...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation based on experimental evidence of HY5 protein interactions. While accurate, this lacks functional specificity about the nature of these interactions. Reason: HY5 does engage in protein binding interactions (particularly with COP1, B-box proteins, and other transcriptional regulators), but the generic "protein binding" term provides limited functional information. More specific terms that capture the functional significance of these interactions would be preferable, but this annotation is not entirely incorrect. Supporting Evidence: PMID:17965270 STH2 encodes a B-box–containing protein that interacts physically with HY5 in yeast and in plant cells
GO:0005515 protein binding	IPI PMID:18796637 LZF1/SALT TOLERANCE HOMOLOG3, an Arabidopsis B-box protein i...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation based on experimental evidence. Represents HY5 interactions but lacks functional specificity. Reason: While HY5 does bind to proteins as demonstrated experimentally, the generic "protein binding" annotation provides limited functional information about the biological significance of these interactions. HY5 protein interactions are functionally important for its regulation and activity, but more specific terms would be more informative. Supporting Evidence: PMID:18796637 STH3 physically interacts with HY5 in vivo
GO:0005515 protein binding	IPI PMID:28650476 CrY2H-seq: a massively multiplexed assay for deep-coverage i...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation supported by experimental evidence of HY5 interactions, but lacks functional specificity. Reason: HY5 participates in protein binding interactions as shown experimentally, but the generic "protein binding" term does not provide meaningful functional information per GO annotation guidelines. These interactions are functionally significant for HY5 regulation but would be better captured by more specific terms. Supporting Evidence: file:ARATH/HY5/HY5-falcon-research.md HY5 [...] interacts with various regulatory proteins such as COP1, HYH, BBX factors, and histone deacetylases PMID:28650476 CrY2H-seq: a massively multiplexed assay for deep-coverage interactome mapping.
GO:0005515 protein binding	IPI PMID:9659918 Molecular interaction between COP1 and HY5 defines a regulat...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation based on seminal experimental evidence of HY5-COP1 interaction. While accurate, this is overly generic for such a functionally important interaction. Reason: This annotation is based on one of the foundational studies demonstrating HY5-COP1 interaction, which is crucial for understanding HY5 regulation. However, the generic "protein binding" term does not capture the functional significance of this regulatory interaction. A more specific term describing transcriptional regulation or protein complex formation would be more informative. Supporting Evidence: PMID:9659918 COP1 interacts directly and specifically with HY5
GO:0005515 protein binding	IPI PMID:9755158 Functional dissection of Arabidopsis COP1 reveals specific r...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation supported by experimental evidence. Represents HY5 interactions but provides limited functional information. Reason: HY5 engages in protein binding interactions as demonstrated experimentally, but the generic "protein binding" annotation lacks specificity about the functional nature of these interactions. While not incorrect, more specific terms would provide better functional annotation. Supporting Evidence: PMID:9755158 COP1's direct interaction with and negative regulation of HY5, a bZIP transcription factor
GO:0005515 protein binding	IPI PMID:28412546 Prefoldins Negatively Regulate Cold Acclimation in Arabidops...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation supported by experimental evidence of HY5 interactions, but lacks functional specificity about the biological significance. Reason: While HY5 does participate in protein binding interactions as shown experimentally, the generic "protein binding" term provides limited functional insight. HY5 interactions are functionally important for transcriptional regulation and protein complex formation, but more specific terms would be more informative. Supporting Evidence: PMID:28412546 Promoting Nuclear Proteasome-Mediated HY5 Degradation
GO:0005634 nucleus	IDA PMID:28412546 Prefoldins Negatively Regulate Cold Acclimation in Arabidops...	ACCEPT	Summary: Nuclear localization annotation with IDA evidence provides direct experimental support for HY5 subcellular localization. This complements other nuclear localization annotations. Reason: Nuclear localization is essential for HY5 function as a transcription factor. This IDA evidence provides direct experimental confirmation of HY5 nuclear localization. Having multiple evidence types (IBA, IEA, IDA) for nuclear localization strengthens the annotation and reflects the well-established nature of this cellular component assignment. Supporting Evidence: PMID:28412546 Nuclear Proteasome-Mediated HY5 Degradation
GO:0009409 response to cold	IEP PMID:28412546 Prefoldins Negatively Regulate Cold Acclimation in Arabidops...	KEEP AS NON CORE	Summary: Response to cold annotation based on expression profiling evidence. HY5 shows altered expression or activity in response to cold stress, representing an environmental response function. Reason: HY5 does respond to cold stress as evidenced by expression profiling, but this is a secondary function compared to its primary role in light signaling and photomorphogenesis. Cold response represents one of the many environmental stresses that HY5 integrates, but it is not a core function of this transcription factor. Supporting Evidence: PMID:28412546 Prefoldins Negatively Regulate Cold Acclimation in Arabidopsis thaliana by Promoting Nuclear Proteasome-Mediated HY5 Degradation
GO:0005515 protein binding	IPI PMID:31061103 HY5 Interacts with the Histone Deacetylase HDA15 to Repress ...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation supported by experimental evidence. While accurate, lacks functional specificity about the biological significance of HY5 protein interactions. Reason: HY5 participates in protein binding interactions as demonstrated experimentally, but the generic "protein binding" annotation provides limited functional information. These interactions are functionally significant for HY5 regulation and activity, but more specific terms describing transcriptional regulation or complex formation would be more informative. Supporting Evidence: PMID:31061103 HY5 Interacts with the Histone Deacetylase HDA15 to Repress Hypocotyl Cell Elongation in Photomorphogenesis
GO:0000976 transcription cis-regulatory region binding	IPI PMID:25352272 Promoter-based integration in plant defense regulation.	ACCEPT	Summary: Transcription cis-regulatory region binding accurately describes HY5s direct molecular function. This annotation represents the specific DNA-binding activity that underlies HY5s role as a transcriptional regulator. Reason: This annotation correctly captures HY5s key molecular function. HY5 directly binds to cis-regulatory elements including G-box sequences in the promoters of light-responsive genes. This is a well-characterized function supported by extensive ChIP-seq and biochemical studies. This annotation is much more informative than generic "protein binding" or "DNA binding" annotations. Supporting Evidence: PMID:25352272 Oct 28. Promoter-based integration in plant defense regulation. file:ARATH/HY5/HY5-deep-research-falcon.md HY5 is best known for binding ACGT-containing motifs, notably G-box/LREs.
GO:0000976 transcription cis-regulatory region binding	IPI PMID:25533953 An Arabidopsis gene regulatory network for secondary cell wa...	ACCEPT	Summary: Duplicate annotation for transcription cis-regulatory region binding with different supporting evidence. This is HY5s core molecular function. Reason: This annotation correctly represents HY5s primary molecular function. Having multiple evidence sources for this key function provides strong support. The different PMIDs suggest multiple studies have independently confirmed HY5s cis-regulatory region binding activity. Supporting Evidence: PMID:25533953 An Arabidopsis gene regulatory network for secondary cell wall synthesis.
GO:0005515 protein binding	IPI PMID:25516599 MicroRNA408 is critical for the HY5-SPL7 gene network that m...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation supported by experimental evidence. Represents HY5 interactions but provides limited functional information about their biological significance. Reason: While HY5 does engage in protein binding interactions as shown experimentally, the generic "protein binding" term lacks specificity about the functional nature of these interactions. HY5 protein interactions are important for its transcriptional regulatory functions, but more specific terms would provide better functional annotation. Supporting Evidence: PMID:25516599 MicroRNA408 is critical for the HY5-SPL7 gene network that mediates the coordinated response to light and copper
GO:0005515 protein binding	IPI PMID:26474641 Short Hypocotyl in White Light1 Interacts with Elongated Hyp...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation based on experimental evidence of HY5 interactions with SHW1 and COP1. While accurate, this lacks functional specificity. Reason: This annotation is supported by important experimental evidence showing HY5 interactions with SHW1 and COP1, which are crucial for HY5 regulation. However, the generic "protein binding" term does not capture the functional significance of these regulatory interactions. More specific terms describing transcriptional regulation would be more informative. Supporting Evidence: PMID:26474641 SHW1 physically interacts with both COP1 and HY5... SHW1 promotes COP1-mediated degradation of HY5 through enhanced ubiquitylation in the darkness
GO:0005634 nucleus	IDA PMID:26474641 Short Hypocotyl in White Light1 Interacts with Elongated Hyp...	ACCEPT	Summary: Nuclear localization annotation with IDA evidence from the SHW1 study provides direct experimental support for HY5 subcellular localization. Reason: Nuclear localization is essential for HY5 function as a transcription factor. This IDA evidence provides direct experimental confirmation from the SHW1 interaction study. Having multiple independent studies confirming nuclear localization strengthens this well-established annotation. Supporting Evidence: PMID:26474641 SHW1 physically interacts with both COP1 and HY5... enhanced ubiquitylation in the darkness [implying nuclear localization for these interactions]
GO:0009787 regulation of abscisic acid-activated signaling pathway	IMP PMID:26474641 Short Hypocotyl in White Light1 Interacts with Elongated Hyp...	KEEP AS NON CORE	Summary: HY5 involvement in ABA signaling regulation is supported by mutant phenotype studies showing altered ABA responsiveness in hy5 mutants. This represents integration of light and hormone signaling pathways. Reason: While HY5 does regulate ABA signaling pathways as evidenced by altered ABA responsiveness in hy5 mutants, this is a secondary function compared to its primary role in light signaling and photomorphogenesis. HY5 acts as an integrator of multiple signaling pathways, but ABA regulation is not its core function. Supporting Evidence: PMID:26474641 the altered abscisic acid responsiveness of hy5 mutants is modulated by additional loss of SHW1 function
GO:0009958 positive gravitropism	IMP PMID:26474641 Short Hypocotyl in White Light1 Interacts with Elongated Hyp...	KEEP AS NON CORE	Summary: HY5 involvement in gravitropism is supported by studies showing that hy5 mutants have gravitropic root growth defects, which can be suppressed by additional mutations. Reason: While HY5 does affect gravitropic responses as evidenced by mutant phenotypes, this is a secondary function compared to its primary role in light signaling and photomorphogenesis. Gravitropism regulation appears to be an indirect consequence of HY5s broader regulatory effects rather than a core function. Supporting Evidence: PMID:26474641 Additional mutation of SHW1 in hy5 mutant background is able to suppress the gravitropic root growth defect of hy5 mutants
GO:0000976 transcription cis-regulatory region binding	IMP PMID:17001643 Intrinsically unstructured N-terminal domain of bZIP transcr...	ACCEPT	Summary: Third annotation for transcription cis-regulatory region binding, this time with IMP evidence from mutant phenotype studies. This represents HY5s core molecular function. Reason: This annotation correctly represents HY5s primary molecular function. The IMP evidence from mutant studies provides strong support for this function. Having multiple lines of evidence (IPI and IMP) for this core function strengthens the annotation confidence. Supporting Evidence: PMID:17001643 Intrinsically unstructured N-terminal domain of bZIP transcription factor HY5.
GO:0032993 protein-DNA complex	IMP PMID:17001643 Intrinsically unstructured N-terminal domain of bZIP transcr...	ACCEPT	Summary: Protein-DNA complex annotation reflects HY5s formation of stable complexes with DNA through its bZIP domain. This is consistent with its role as a DNA-binding transcription factor. Reason: This annotation accurately represents the cellular component where HY5 functions. As a transcription factor, HY5 forms protein-DNA complexes when bound to target gene promoters. This is consistent with its DNA-binding activity and transcriptional regulatory function. Supporting Evidence: PMID:17001643 Intrinsically unstructured N-terminal domain of bZIP transcription factor HY5.
GO:0005515 protein binding	IPI PMID:21632973 BBX32, an Arabidopsis B-Box protein, functions in light sign...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation supported by experimental evidence. Represents HY5 interactions with B-box proteins but lacks functional specificity. Reason: HY5 does participate in protein binding interactions with B-box proteins as demonstrated experimentally, but the generic "protein binding" annotation provides limited functional information. These interactions are functionally important for light signaling regulation, but more specific terms would be more informative. Supporting Evidence: PMID:21632973 BBX32, an Arabidopsis B-Box protein, functions in light signaling by suppressing HY5-regulated gene expression and interacting with STH2/BBX21
GO:0005515 protein binding	IPI PMID:23624715 The Arabidopsis B-BOX protein BBX25 interacts with HY5, nega...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation based on experimental evidence of HY5 interactions with BBX25. While accurate, lacks functional specificity. Reason: HY5 engages in protein binding interactions with BBX25 as demonstrated experimentally, but the generic "protein binding" term does not capture the functional significance of these interactions in regulating seedling photomorphogenesis. More specific terms describing transcriptional regulation would be more informative. Supporting Evidence: PMID:23624715 The Arabidopsis B-BOX protein BBX25 interacts with HY5, negatively regulating BBX22 expression to suppress seedling photomorphogenesis
GO:0005515 protein binding	IPI PMID:23733077 Molecular interactions of BBX24 and BBX25 with HYH, HY5 HOMO...	MARK AS OVER ANNOTATED	Summary: Generic protein binding annotation supported by experimental evidence of HY5 interactions with BBX24 and BBX25. Accurate but lacks functional specificity. Reason: HY5 participates in protein binding interactions with B-box proteins BBX24 and BBX25 as shown experimentally, but the generic "protein binding" annotation provides limited functional insight. These interactions are functionally significant for modulating seedling development, but more specific terms would be more informative. Supporting Evidence: PMID:23733077 Molecular interactions of BBX24 and BBX25 with HYH, HY5 HOMOLOG, to modulate Arabidopsis seedling development
GO:0005634 nucleus	IDA PMID:20031914 The clock protein CCA1 and the bZIP transcription factor HY5...	ACCEPT	Summary: Nuclear localization annotation with IDA evidence provides direct experimental support for HY5 subcellular localization from circadian clock study. Reason: Nuclear localization is essential for HY5 function as a transcription factor. This IDA evidence from the CCA1-HY5 interaction study provides additional direct experimental confirmation of nuclear localization. Multiple independent studies confirming this cellular component assignment strengthen the annotation. Supporting Evidence: PMID:20031914 The clock protein CCA1 and the bZIP transcription factor HY5 physically interact to regulate gene expression in Arabidopsis [implying nuclear co-localization]
GO:0042753 positive regulation of circadian rhythm	IMP PMID:21499259 Coordinated transcriptional regulation underlying the circad...	KEEP AS NON CORE	Summary: Positive regulation of circadian rhythm annotation based on mutant phenotype evidence. HY5 affects circadian rhythm regulation through its interactions with clock components. Reason: HY5 does influence circadian rhythm regulation as evidenced by mutant phenotypes and interactions with clock proteins like CCA1, but this is a secondary function compared to its primary role in light signaling and photomorphogenesis. HY5 integrates light and circadian signals, but circadian regulation is not its core function. Supporting Evidence: PMID:21499259 Coordinated transcriptional regulation underlying the circadian clock in Arabidopsis
GO:0010224 response to UV-B	IEP PMID:18266923 Identification of a novel cis-regulatory element for UV-B-in...	ACCEPT	Summary: Response to UV-B annotation based on expression profiling evidence. HY5 responds to UV-B radiation as part of its broader light signaling functions. Reason: UV-B response is a well-established function of HY5 that complements its core role in light signaling. HY5 integrates multiple light wavelengths including UV-B and is required for proper UV-B responses. This represents an important aspect of HY5s light signaling function, though it is secondary to its role in visible light responses. Supporting Evidence: PMID:18266923 Identification of a novel cis-regulatory element for UV-B-induced transcription in Arabidopsis file:ARATH/HY5/HY5-deep-research-falcon.md HY5 is also a key transcriptional regulator under UV-B. In a landmark Plant Cell study, COP1 was required for low-UV-B responses and HY5 gene activation; under supplementary UV-B, COP1 and HY5 accumulated in the nucleus, and UV-B-triggered flavonoid accumulation and genome-wide UV-B-responsive expression changes were largely blocked in cop1 mutants. This positions HY5 as a major effector of UV-B acclimation programs (e.g., via CHS/flavonoid pathways).
GO:0003690 double-stranded DNA binding	IPI PMID:18332440 Integration of light and abscisic acid signaling during seed...	ACCEPT	Summary: Double-stranded DNA binding annotation based on experimental evidence. This describes HY5s molecular mechanism of DNA binding through its bZIP domain. Reason: This annotation correctly describes HY5s molecular function. As a bZIP transcription factor, HY5 binds to double-stranded DNA through its basic region and leucine zipper domains. This is more specific than generic "DNA binding" and accurately represents the molecular mechanism by which HY5 recognizes its target sequences. Supporting Evidence: PMID:18332440 Integration of light and abscisic acid signaling during seed germination and early seedling development
GO:0009740 gibberellic acid mediated signaling pathway	IMP PMID:18053005 Gibberellins modulate light signaling pathways to prevent Ar...	KEEP AS NON CORE	Summary: Gibberellic acid mediated signaling pathway annotation based on mutant phenotype evidence. HY5 influences GA signaling as part of hormone-light signaling integration. Reason: HY5 does affect gibberellic acid signaling pathways as evidenced by mutant phenotype studies, but this is a secondary function compared to its primary role in light signaling and photomorphogenesis. HY5 integrates multiple signaling pathways including hormonal responses, but GA signaling is not its core function. Supporting Evidence: PMID:18053005 Gibberellins modulate light signaling pathways to prevent Arabidopsis seedling de-etiolation in darkness
GO:0010099 regulation of photomorphogenesis	IMP PMID:18053005 Gibberellins modulate light signaling pathways to prevent Ar...	ACCEPT	Summary: Regulation of photomorphogenesis annotation with IMP evidence from mutant studies. This duplicates the IBA annotation but with stronger experimental evidence. Reason: This annotation correctly represents HY5s core biological function. The IMP evidence from mutant phenotype studies provides strong experimental support for HY5s role in regulating photomorphogenesis. Having both IBA and IMP evidence for this core function strengthens the annotation confidence. Supporting Evidence: PMID:18053005 Gibberellins modulate light signaling pathways to prevent Arabidopsis seedling de-etiolation in darkness
GO:0009737 response to abscisic acid	IMP PMID:18332440 Integration of light and abscisic acid signaling during seed...	KEEP AS NON CORE	Summary: Response to abscisic acid annotation based on mutant phenotype evidence. HY5 affects ABA responses as part of hormone-light signaling integration. Reason: HY5 does influence ABA responses as evidenced by mutant phenotype studies, but this is a secondary function compared to its primary role in light signaling and photomorphogenesis. HY5 integrates light and hormone signaling pathways, but ABA response is not its core function. Supporting Evidence: PMID:18332440 Integration of light and abscisic acid signaling during seed germination and early seedling development
GO:0003677 DNA binding	IDA PMID:17319847 PIF3 regulates anthocyanin biosynthesis in an HY5-dependent ...	MODIFY	Summary: DNA binding annotation with IDA evidence provides direct experimental support for HY5s molecular function as a DNA-binding protein. Reason: While DNA binding is accurate and supported by direct experimental evidence (IDA), this is too general compared to more specific annotations like "transcription cis-regulatory region binding" or "double-stranded DNA binding" that are also present. The more specific terms better capture HY5s function and should be preferred. Proposed replacements: transcription cis-regulatory region binding Supporting Evidence: PMID:17319847 PIF3 regulates anthocyanin biosynthesis in an HY5-dependent manner with both factors directly binding anthocyanin biosynthetic gene promoters
GO:0010017 red or far-red light signaling pathway	IMP PMID:16891401 Functional profiling reveals that only a small number of phy...	ACCEPT	Summary: Red or far-red light signaling pathway annotation with IMP evidence from mutant studies. This duplicates earlier annotations but with stronger experimental evidence. Reason: This annotation correctly represents HY5s core function in light signaling. The IMP evidence from mutant phenotype studies provides strong experimental support. Having multiple evidence types (IBA, IEA, IMP) for this core function strengthens the annotation and reflects the well-established nature of HY5s role in red/far-red light signaling. Supporting Evidence: PMID:16891401 only a small number of phytochrome-regulated early-response genes in Arabidopsis are necessary for optimal deetiolation
GO:0031539 positive regulation of anthocyanin metabolic process	IMP PMID:17319847 PIF3 regulates anthocyanin biosynthesis in an HY5-dependent ...	ACCEPT	Summary: Positive regulation of anthocyanin metabolic process annotation based on mutant phenotype evidence. HY5 directly regulates anthocyanin biosynthetic genes. Reason: This annotation correctly represents an important specific function of HY5. HY5 directly binds to and regulates anthocyanin biosynthetic gene promoters, making this a well-established function supported by both genetic and molecular evidence. Anthocyanin regulation is a key downstream output of HY5s transcriptional activity. Supporting Evidence: PMID:17319847 PIF3 regulates anthocyanin biosynthesis in an HY5-dependent manner with both factors directly binding anthocyanin biosynthetic gene promoters file:ARATH/HY5/HY5-deep-research-falcon.md Classic examples include RBCS-1A (photosynthetic gene) and CHS (chalcone synthase; flavonoid biosynthesis), where direct promoter binding and HY5-dependence were demonstrated in early mechanistic studies.
GO:0010114 response to red light	IEP PMID:17076805 phyA dominates in transduction of red-light signals to rapid...	ACCEPT	Summary: Response to red light annotation with IEP evidence from expression profiling. This duplicates the IBA annotation but with expression-based evidence. Reason: This annotation correctly captures HY5s role in red light responses. The IEP evidence from expression profiling provides additional support beyond the IBA annotation. Having multiple evidence types for this core function strengthens the annotation and demonstrates HY5s consistent involvement in red light signaling. Supporting Evidence: PMID:17076805 phyA dominates in transduction of red-light signals to rapidly responding genes at the initiation of Arabidopsis seedling de-etiolation
GO:0010218 response to far red light	IEP PMID:17076805 phyA dominates in transduction of red-light signals to rapid...	ACCEPT	Summary: Response to far red light annotation with IEP evidence from expression profiling. This duplicates the IBA annotation but with expression-based evidence. Reason: This annotation correctly represents HY5s role in far-red light responses. The IEP evidence from expression profiling provides additional support beyond the IBA annotation. Having multiple evidence types for this core function strengthens the annotation and demonstrates HY5s consistent involvement in far-red light signaling. Supporting Evidence: PMID:17076805 phyA dominates in transduction of red-light signals to rapidly responding genes at the initiation of Arabidopsis seedling de-etiolation
GO:0005634 nucleus	IDA PMID:16829591 CONSTITUTIVELY PHOTOMORPHOGENIC1 is required for the UV-B re...	ACCEPT	Summary: Nuclear localization annotation with IDA evidence provides direct experimental support for HY5 subcellular localization from early characterization studies. Reason: Nuclear localization is essential for HY5 function as a transcription factor. This IDA evidence from early characterization studies provides direct experimental confirmation. Multiple independent studies with IDA evidence strengthen this well-established cellular component annotation. Supporting Evidence: PMID:16829591 CONSTITUTIVELY PHOTOMORPHOGENIC1 is required for the UV-B response in Arabidopsis
GO:0009963 positive regulation of flavonoid biosynthetic process	IMP PMID:16829591 CONSTITUTIVELY PHOTOMORPHOGENIC1 is required for the UV-B re...	ACCEPT	Summary: Positive regulation of flavonoid biosynthetic process annotation based on mutant phenotype evidence. HY5 regulates flavonoid biosynthesis as part of its role in secondary metabolite production. Reason: This annotation correctly represents an important specific function of HY5. HY5 regulates flavonoid biosynthetic genes, including anthocyanins and other flavonoids, which are important for plant responses to light stress and UV protection. This is a well-established downstream function of HY5s transcriptional activity. Supporting Evidence: PMID:16829591 CONSTITUTIVELY PHOTOMORPHOGENIC1 is required for the UV-B response in Arabidopsis file:ARATH/HY5/HY5-deep-research-falcon.md Classic examples include RBCS-1A (photosynthetic gene) and CHS (chalcone synthase; flavonoid biosynthesis), where direct promoter binding and HY5-dependence were demonstrated in early mechanistic studies.
GO:0010224 response to UV-B	IMP PMID:16829591 CONSTITUTIVELY PHOTOMORPHOGENIC1 is required for the UV-B re...	ACCEPT	Summary: Response to UV-B annotation with IMP evidence from mutant studies. This duplicates the IEP annotation but with stronger experimental evidence from genetic studies. Reason: UV-B response is a well-established function of HY5. The IMP evidence from mutant studies provides strong experimental support beyond expression profiling. HY5 is required for proper UV-B responses and integrates UV-B signaling with other light responses. This represents an important aspect of HY5s light signaling function. Supporting Evidence: PMID:16829591 CONSTITUTIVELY PHOTOMORPHOGENIC1 is required for the UV-B response in Arabidopsis
GO:0005634 nucleus	IDA PMID:9367981 The Arabidopsis HY5 gene encodes a bZIP protein that regulat...	ACCEPT	Summary: Nuclear localization annotation with IDA evidence from seminal HY5 characterization study provides foundational experimental support. Reason: Nuclear localization is essential for HY5 function as a transcription factor. This IDA evidence from the foundational HY5 characterization study provides important historical experimental confirmation. Multiple IDA evidence sources strengthen this well-established cellular component annotation. Supporting Evidence: PMID:9367981 The Arabidopsis HY5 gene encodes a bZIP protein that regulates stimulus-induced development of root and hypocotyl
GO:0010224 response to UV-B	IGI PMID:14739338 Genome-wide analysis of gene expression reveals function of ...	ACCEPT	Summary: Response to UV-B annotation with IGI evidence from genetic interaction studies. HY5 involvement in UV-B responses is supported by genetic interaction data. Reason: UV-B response is a well-established function of HY5. The IGI evidence from genetic interaction studies provides additional experimental support for HY5s role in UV-B responses. This complements the other UV-B annotations and demonstrates HY5s consistent involvement in UV-B signaling across multiple experimental approaches. Supporting Evidence: PMID:14739338 Genome-wide analysis of gene expression reveals function of the bZIP transcription factor HY5 in the UV-B response of Arabidopsis
GO:0003700 DNA-binding transcription factor activity	ISS PMID:11906833 bZIP transcription factors in Arabidopsis.	ACCEPT	Summary: DNA-binding transcription factor activity annotation with ISS evidence based on sequence similarity. This represents HY5s core molecular function. Reason: This annotation correctly represents HY5s primary molecular function. The ISS evidence based on sequence similarity is appropriate for this well-conserved function of bZIP transcription factors. This annotation complements the more specific molecular function annotations and provides additional evidence for HY5s transcriptional activity. Supporting Evidence: PMID:11906833 bZIP transcription factors in Arabidopsis
GO:0003700 DNA-binding transcription factor activity	ISS PMID:11118137 Arabidopsis transcription factors: genome-wide comparative a...	ACCEPT	Summary: DNA-binding transcription factor activity annotation with ISS evidence based on sequence similarity. Duplicates other transcription factor annotations but provides additional support. Reason: This annotation correctly represents HY5s primary molecular function. While it duplicates other transcription factor activity annotations, the ISS evidence provides additional computational support based on sequence similarity. Multiple evidence types for this core function strengthen the annotation confidence. Supporting Evidence: PMID:11118137 Arabidopsis transcription factors: genome-wide comparative analysis among eukaryotes
GO:0003677 DNA binding	IDA PMID:9596629 Arabidopsis bZIP protein HY5 directly interacts with light-r...	MODIFY	Summary: DNA binding annotation with IDA evidence provides direct experimental support for HY5s molecular function, but is less specific than other DNA binding annotations. Reason: While DNA binding is accurate and supported by direct experimental evidence, this is too general compared to more specific annotations like "transcription cis-regulatory region binding" and "double-stranded DNA binding" that are also present. The more specific terms better capture HY5s function and should be preferred to avoid redundant generic annotations. Proposed replacements: transcription cis-regulatory region binding Supporting Evidence: PMID:9596629 Arabidopsis bZIP protein HY5 directly interacts with light-responsive promoters in mediating light control of gene expression
GO:0003700 DNA-binding transcription factor activity	TAS PMID:11019812 A genomic perspective on plant transcription factors.	ACCEPT	Summary: DNA-binding transcription factor activity annotation with TAS evidence from traceable author statements. This represents HY5s core molecular function. Reason: This annotation correctly represents HY5s primary molecular function. The TAS evidence from traceable author statements provides strong literature support. While this duplicates other transcription factor activity annotations, having multiple evidence types including author statements strengthens the annotation confidence for this core function. Supporting Evidence: PMID:11019812 A genomic perspective on plant transcription factors
GO:0005634 nucleus	IDA PMID:9596629 Arabidopsis bZIP protein HY5 directly interacts with light-r...	ACCEPT	Summary: Nuclear localization annotation with IDA evidence from seminal study demonstrating HY5 direct interaction with light-responsive promoters. Reason: Nuclear localization is essential for HY5 function as a transcription factor. This IDA evidence from the foundational study showing HY5 direct promoter binding provides important experimental confirmation. Multiple IDA evidence sources from different studies strengthen this well-established cellular component annotation. Supporting Evidence: PMID:9596629 Arabidopsis bZIP protein HY5 directly interacts with light-responsive promoters in mediating light control of gene expression
GO:0006355 regulation of DNA-templated transcription	TAS PMID:11019812 A genomic perspective on plant transcription factors.	ACCEPT	Summary: Regulation of DNA-templated transcription annotation with TAS evidence from traceable author statements. This accurately describes HY5s biological function. Reason: This annotation correctly describes HY5s core biological function as a transcriptional regulator. The TAS evidence from traceable author statements provides strong literature support. While general, this annotation accurately captures the fundamental biological process in which HY5 participates and complements the more specific molecular function annotations. Supporting Evidence: PMID:11019812 A genomic perspective on plant transcription factors
GO:0009640 photomorphogenesis	TAS PMID:10990463 HY5 stability and activity in arabidopsis is regulated by ph...	ACCEPT	Summary: Photomorphogenesis annotation with TAS evidence represents HY5s core biological function. This is the direct process that HY5 regulates, complementing the "regulation of photomorphogenesis" annotation. Reason: This annotation correctly identifies HY5s involvement in photomorphogenesis. The TAS evidence indicates traceable author statements from the literature. While this duplicates the concept in "regulation of photomorphogenesis", it represents the process itself rather than its regulation, providing a complete picture of HY5s role. Supporting Evidence: PMID:10990463 HY5 is a bZIP transcription factor that promotes photomorphogenesis file:ARATH/HY5/HY5-deep-research-falcon.md Mechanistically, HY5 functions as a positive regulator of photomorphogenesis (de-etiolation) downstream of multiple photoreceptors, with loss-of-function hy5 mutants displaying long hypocotyl phenotypes under diverse light conditions.
GO:0009640 photomorphogenesis	TAS PMID:11145879 The COP/DET/FUS proteins-regulators of eukaryotic growth and...	ACCEPT	Summary: Duplicate photomorphogenesis annotation with different supporting evidence. Multiple citations strengthen the evidence for HY5s core function. Reason: This annotation correctly identifies HY5s core function. Having multiple TAS evidence sources for photomorphogenesis provides strong literature support. The different PMID indicates independent confirmation of HY5s role in photomorphogenesis. Supporting Evidence: PMID:11145879 The COP/DET/FUS proteins-regulators of eukaryotic growth and development.
GO:0009639 response to red or far red light	NAS	NEW	Summary: Added to align core_functions with existing annotations. Reason: Core function term not present in existing_annotations.

Gene Description

Proposed New Ontology Terms

multi-photoreceptor signal integration

Existing Annotations Review

Core Functions

Functions as transcriptional activator that promotes photomorphogenesis by integrating multiple light signaling pathways

References

Deep Research

Falcon

Perplexity

📚 Additional Documentation

Falcon Research

📄 View Raw YAML