SWI3

Existing Annotations Review

Gene Description

Existing Annotations Review

Core Functions

Chromatin remodeling through histone interactions - SWI3 interacts with histone H3 and H4 tails (particularly acetylated forms) to facilitate complex nucleosome engagement and ATP-dependent remodeling that controls transcriptional access to chromatin

References

Deep Research

Falcon

Perplexity

📄 View Raw YAML

GO Term	Evidence	Action	Reason
GO:0045893 positive regulation of DNA-templated transcription	IBA GO_REF:0000033	ACCEPT	Summary: SWI3 is a core component of the SWI/SNF complex, which activates transcription through ATP-dependent nucleosome remodeling. The complex is recruited to promoters by transcription factors and remodels nucleosomes to facilitate transcription factor binding and RNA polymerase II recruitment. IBA evidence is appropriate as this function is conserved across eukaryotes. This is a primary function of SWI3. Reason: SWI3 function as part of the SWI/SNF complex in positive transcriptional regulation is extensively documented and represents a core function. The complex is required for transcriptional activation of approximately 5% of yeast genes. This is supported by conservation across organisms (mammalian BAF155/170, plant ATSWI3 orthologs). Supporting Evidence: PMID:1339306 Characterization of the yeast SWI1, SWI2, and SWI3 genes, which encode a global activator of transcription. PMID:8159677 Five SWI/SNF gene products are components of a large multisubunit complex required for transcriptional enhancement. file:yeast/SWI3/SWI3-deep-research-perplexity.md provider: perplexity
GO:0016514 SWI/SNF complex	IBA GO_REF:0000033	ACCEPT	Summary: SWI3 is a structural component and core subunit of the SWI/SNF complex. The complex is composed of 11 subunits including SWI3, which exists as a homodimer and mediates interactions with multiple other subunits through its SWIRM and SANT domains. SWI3 is essential for complex assembly and stability. Reason: This annotation represents a primary and core function - SWI3 is literally a component of the SWI/SNF complex. Genetic evidence shows that deletion of SWI3 abolishes functional complex formation. UniProt explicitly identifies SWI3 as a component of the 1.14 MDa SWI/SNF complex with specific stoichiometry (2 copies of SWI3 per complex). Supporting Evidence: PMID:8127913 A multisubunit complex containing the SWI1/ADR6, SWI2/SNF2, SWI3, SNF5, and SNF6 gene products isolated from yeast. PMID:18644858 Architecture of the SWI/SNF-nucleosome complex. PMID:32636384 Swi1 and Swi3 form the backbone of the complex and closely connect with surrounding subunits. PMID:32636384 the Swi3 dimer, consisting of coiled-coils, SANT, and SWIRM domains, forms an file:yeast/SWI3/SWI3-deep-research-falcon.md The model contains two Swi3 instances (Swi3A and Swi3B). file:yeast/SWI3/SWI3-deep-research-falcon.md Swi1 and Swi3 together form a major structural backbone of the complex.
GO:0042393 histone binding	IBA GO_REF:0000033	ACCEPT	Summary: SWI3 physically interacts with histone H3 and H4 tails, as demonstrated by crosslinking studies showing that H3 acetylation alters SWI3 crosslinking patterns at histone tails. This binding is part of the complex's nucleosome engagement mechanism, though SWI3 is not the primary histone-binding component. Reason: SWI3 demonstrates histone binding capability through biochemical evidence. Acetylated H3 tails alter crosslinking of SWI3 to histone residues, indicating specific interactions. This binding is functional for nucleosome recognition and remodeling. However, this is less central than complex membership or transcriptional roles. Supporting Evidence: PMID:17496903 Swi3p controls SWI/SNF assembly and ATP-dependent H2A-H2B displacement.
GO:0003677 DNA binding	IEA GO_REF:0000120	ACCEPT	Summary: SWI3 contains the SWIRM domain, which directly binds DNA. Crystallographic and in vitro biochemical work on the isolated Swi3 SWIRM domain shows nucleic-acid (DNA/nucleosomal/cruciform DNA) binding with apparent Kd ~72-105 nM, and structure-guided SWIRM mutations (D374A, K383D/K387D, N392A) abolish DNA binding. UniProt records a curated DNA binding annotation (GO:0003677, IDA:SGD), the DNA-binding keyword, and these mutagenesis residues as "Loss of DNA-binding". This IEA annotation is therefore consistent with direct functional evidence. Reason: Earlier review reasoning (REMOVE) is overturned by direct biochemical evidence from falcon deep research and by UniProt's curated SGD IDA annotation: the Swi3 SWIRM domain does bind DNA in vitro, and SWIRM point mutations specifically abolish DNA binding. This electronic (IEA) annotation is consistent with, though weaker than, the experimentally evidenced (IDA/IMP) DNA binding annotations from PMID:16461455, and is accepted for consistency. Supporting Evidence: PMID:16461455 Structure and function of the SWIRM domain, a conserved protein module found in chromatin regulatory complexes. file:yeast/SWI3/SWI3-deep-research-falcon.md the SWIRM domain of Swi3 is a conserved structural module whose structure and biochemical function were experimentally characterized; it can bind DNA (and nucleosomal DNA) and contributes to SWI/SNF assembly and stability.
GO:0005634 nucleus	IEA GO_REF:0000044	KEEP AS NON CORE	Summary: SWI3 localizes to the nucleus as part of the SWI/SNF complex. However, under hypoxia, SWI3 undergoes rapid relocalization to the cytosol, suggesting oxygen-dependent regulation of subcellular localization. This is a well-established localization pattern. Reason: Nuclear localization is accurate but represents a cellular location characteristic rather than a functional property. While SWI3 typically resides in the nucleus, this is secondary to its functional roles. Importantly, SWI3 localization is dynamically regulated - it relocates to the cytosol during hypoxia, indicating this is not a static feature. Supporting Evidence: PMID:22932476 The nuclear localization of SWI/SNF proteins is subjected to oxygen regulation. file:yeast/SWI3/SWI3-deep-research-falcon.md Swi3 is predominantly nuclear under normoxia but undergoes regulated cytosolic relocalization under hypoxia (>95% cytosolic)
GO:0006338 chromatin remodeling	IEA GO_REF:0000117	ACCEPT	Summary: SWI3 is essential for ATP-dependent chromatin remodeling through its role as a structural component of the SWI/SNF complex. The complex remodels nucleosomes through SWI1/SWI2 ATPase activity, with SWI3 controlling remodeling efficiency and nucleosome displacement. This is a primary functional role of the complex. Reason: Chromatin remodeling is a core function of the SWI/SNF complex, in which SWI3 plays a critical regulatory role. SWI3 controls ATP-dependent H2A-H2B displacement efficiency and modulates complex function. The annotation is well-supported by experimental evidence. Supporting Evidence: PMID:8016655 Stimulation of GAL4 derivative binding to nucleosomal DNA by the yeast SWI/SNF complex. PMID:11163188 Generation of superhelical torsion by ATP-dependent chromatin remodeling activities. file:yeast/SWI3/SWI3-deep-research-falcon.md the SWIRM domain of Swi3 is a conserved structural module whose structure and biochemical function were experimentally characterized; it can bind DNA (and nucleosomal DNA) and contributes to SWI/SNF assembly and stability.
GO:0006351 DNA-templated transcription	IEA GO_REF:0000043	ACCEPT	Summary: SWI3 participates in DNA-templated transcription through its role as part of the SWI/SNF complex, which facilitates transcription initiation and elongation through chromatin remodeling. This is an indirect role mediated through complex assembly and function, not a direct transcriptional activity. Reason: Although SWI3 does not directly catalyze transcription, it is a required component of the SWI/SNF complex that facilitates transcription through nucleosome remodeling. SWI3 is needed for approximately 5% of yeast genes to achieve normal transcriptional levels. Supporting Evidence: PMID:1339306 Characterization of the yeast SWI1, SWI2, and SWI3 genes, which encode a global activator of transcription.
GO:0006355 regulation of DNA-templated transcription	IEA GO_REF:0000117	ACCEPT	Summary: SWI3 regulates transcription through multiple mechanisms including directing the SWI/SNF complex to target genes, controlling remodeling efficiency, and integrating regulatory signals through histone modification recognition and transcription factor interactions. This is the primary functional role of SWI3. Reason: Transcriptional regulation is a core function of SWI3. The complex is required for both positive and negative regulation through transcriptional interference. SWI3 specifically plays roles in cell cycle-dependent transcription (HO gene), cell wall stress responses, and oxygen-dependent gene regulation. Morse et al. (2024) provide direct evidence that Swi/Snf, via the structural subunit Swi3 (swi3-E815X allele), contributes to gene repression through co-transcriptional nucleosome remodeling and transcriptional interference at tandem promoters. Supporting Evidence: PMID:28249159 Composition and Function of Mutant Swi/Snf Complexes. PMID:39043178 swi3-E815X, a nonsense mutant affecting the structural subunit Swi3, for further investigation PMID:39043178 swi3-E815X mutation also reduces repressive activity by Swi/Snf at the TSSPROX but to a lesser extent than the snf2-W935R mutant. file:yeast/SWI3/SWI3-deep-research-falcon.md A 2024 Molecular Cell study found that SWI/SNF remodeling regulates transcriptional interference and gene repression.
GO:0005515 protein binding	IPI PMID:12805231 The nuclear actin-related proteins Arp7 and Arp9 a dimeric m...	KEEP AS NON CORE	Summary: SWI3 interacts with ARP7 (subunit P53628), SNF6 (subunit Q05123), and SNF5 (subunit Q12406) as documented in the IntAct database from yeast two-hybrid and biochemical studies. These are core interactions within the SWI/SNF complex. Reason: While protein binding interactions are documented and correct, the annotation is non-specific and generic. SWI3 is known to function through protein-protein interactions with specific subunits; these interactions should ideally be captured in more specific molecular function terms (e.g., structural organization of complex). "Protein binding" is uninformative and over-represents the non-specific nature of the annotation. Supporting Evidence: PMID:12805231 The nuclear actin-related proteins Arp7 and Arp9: a dimeric module that cooperates with architectural proteins for chromatin remodeling.
GO:0005515 protein binding	IPI PMID:14660704 Applicability of tandem affinity purification MudPIT to path...	KEEP AS NON CORE	Summary: SWI3 protein binding documented through proteomic analysis of chromatin-modifying complexes in yeast. Reason: Generic protein binding annotation. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:14660704 Epub 2003 Dec 5. Applicability of tandem affinity purification MudPIT to pathway proteomics in yeast.
GO:0005515 protein binding	IPI PMID:15506919 Proteomic analysis of chromatin-modifying complexes in Sacch...	KEEP AS NON CORE	Summary: SWI3 protein binding identified through proteomic analysis of chromatin-modifying complexes, identifying novel subunits and interactions. Reason: Generic protein binding annotation. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:15506919 Proteomic analysis of chromatin-modifying complexes in Saccharomyces cerevisiae identifies novel subunits.
GO:0005515 protein binding	IPI PMID:16204215 The RSC chromatin remodeling complex bears an essential fung...	KEEP AS NON CORE	Summary: SWI3 interacts with SWP82, an essential fungal-specific protein module component of the RSC complex. Reason: Generic protein binding annotation. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:16204215 Oct 3. The RSC chromatin remodeling complex bears an essential fungal-specific protein module with broad functional roles.
GO:0005515 protein binding	IPI PMID:16429126 Proteome survey reveals modularity of the yeast cell machine...	KEEP AS NON CORE	Summary: SWI3 protein binding interactions identified through global proteome survey revealing modularity of the yeast cell machinery. Reason: Generic protein binding annotation from large-scale proteomics. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:16429126 Proteome survey reveals modularity of the yeast cell machinery.
GO:0005515 protein binding	IPI PMID:16554755 Global landscape of protein complexes in the yeast Saccharom...	KEEP AS NON CORE	Summary: SWI3 protein binding interactions identified through global landscape of protein complexes in yeast. Reason: Generic protein binding annotation from proteomics. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:16554755 Global landscape of protein complexes in the yeast Saccharomyces cerevisiae.
GO:0005515 protein binding	IPI PMID:17496903 Swi3p controls SWI/SNF assembly and ATP-dependent H2A-H2B di...	KEEP AS NON CORE	Summary: SWI3 protein binding interactions with histone H2A, H2B, H3, and H4 documented as part of nucleosome interaction mechanism. SWI3 controls assembly and ATP-dependent H2A-H2B displacement. Reason: Generic protein binding annotation. While SWI3 physically interacts with histones as part of nucleosome remodeling, this is more specifically captured by GO:0042393 (histone binding). The generic "protein binding" term is too vague. Supporting Evidence: PMID:17496903 May 13. Swi3p controls SWI/SNF assembly and ATP-dependent H2A-H2B displacement.
GO:0005515 protein binding	IPI PMID:32188938 Cryo-EM structure of SWI/SNF complex bound to a nucleosome	KEEP AS NON CORE	Summary: SWI3 protein binding interactions documented in cryo-EM structure of SWI/SNF complex bound to nucleosome. Reason: Generic protein binding annotation. While structural evidence confirms interactions, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:32188938 Mar 11. Cryo-EM structure of SWI/SNF complex bound to a nucleosome.
GO:0005515 protein binding	IPI PMID:37968396 The social and structural architecture of the yeast protein ...	KEEP AS NON CORE	Summary: SWI3 protein binding interactions identified through recent social and structural architecture studies of the yeast protein interactome. Reason: Generic protein binding annotation from large-scale interactome studies. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:37968396 Nov 15. The social and structural architecture of the yeast protein interactome.
GO:0005515 protein binding	IPI PMID:7623818 SNF11, a new component of the yeast SNF-SWI complex that int...	KEEP AS NON CORE	Summary: SWI3 protein binding with SNF11, a new component of the yeast SNF-SWI complex that interacts with conserved region of SNF2. Reason: Generic protein binding annotation. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:7623818 SNF11, a new component of the yeast SNF-SWI complex that interacts with a conserved region of SNF2.
GO:0005515 protein binding	IPI PMID:8016655 Stimulation of GAL4 derivative binding to nucleosomal DNA by...	KEEP AS NON CORE	Summary: SWI3 protein binding in context of SWI/SNF complex stimulation of GAL4 binding to nucleosomal DNA. Reason: Generic protein binding annotation. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:8016655 Stimulation of GAL4 derivative binding to nucleosomal DNA by the yeast SWI/SNF complex.
GO:0005515 protein binding	IPI PMID:8127913 A multisubunit complex containing the SWI1/ADR6, SWI2/SNF2, ...	KEEP AS NON CORE	Summary: SWI3 protein binding interactions with SWI1, SNF2, SNF5, and SNF6 subunits documented in initial SWI/SNF complex isolation. Reason: Generic protein binding annotation. While these interactions are foundational to understanding SWI3 function, the generic "protein binding" term is uninformative and should be replaced with more specific functional annotations. Supporting Evidence: PMID:8127913 A multisubunit complex containing the SWI1/ADR6, SWI2/SNF2, SWI3, SNF5, and SNF6 gene products isolated from yeast.
GO:0005515 protein binding	IPI PMID:8668146 TFG/TAF30/ANC1, a component of the yeast SWI/SNF complex tha...	KEEP AS NON CORE	Summary: SWI3 protein binding with TFG/TAF30/ANC1, a component of the yeast SWI/SNF complex similar to leukemogenic proteins. Reason: Generic protein binding annotation. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:8668146 TFG/TAF30/ANC1, a component of the yeast SWI/SNF complex that is similar to the leukemogenic proteins ENL and AF-9.
GO:0005515 protein binding	IPI PMID:9726966 Subunits of the yeast SWI/SNF complex are members of the act...	KEEP AS NON CORE	Summary: SWI3 protein binding with actin-related protein (ARP) family members ARP7 and ARP9 as components of SWI/SNF complex. Reason: Generic protein binding annotation. While interactions are documented, this term is too general to be informative about SWI3's specific molecular function. Supporting Evidence: PMID:9726966 Subunits of the yeast SWI/SNF complex are members of the actin-related protein (ARP) family.
GO:0000785 chromatin	NAS PMID:28249159 Composition and Function of Mutant Swi/Snf Complexes	KEEP AS NON CORE	Summary: SWI3 is located in chromatin as part of the SWI/SNF complex that remodels chromatin structure. This represents the cellular location where SWI3 exerts its function. Reason: Localization to chromatin is accurate and represents the functional location where SWI3 operates. However, this is a localization annotation rather than a functional annotation. The core function is chromatin remodeling, not localization to chromatin. Supporting Evidence: PMID:28249159 Composition and Function of Mutant Swi/Snf Complexes.
GO:0006338 chromatin remodeling	IDA PMID:11163188 Generation of superhelical torsion by ATP-dependent chromati...	ACCEPT	Summary: SWI3-dependent chromatin remodeling documented through direct experimental analysis of superhelical torsion generation by ATP-dependent chromatin remodeling activities. Reason: Direct experimental evidence (IDA) confirms SWI3's role in chromatin remodeling. This is a core function of SWI3 as part of the SWI/SNF complex. IDA evidence is stronger than IEA for the same annotation. Supporting Evidence: PMID:11163188 Generation of superhelical torsion by ATP-dependent chromatin remodeling activities.
GO:0006357 regulation of transcription by RNA polymerase II	IDA PMID:28249159 Composition and Function of Mutant Swi/Snf Complexes	ACCEPT	Summary: SWI3-dependent regulation of RNA polymerase II transcription documented through direct experimental analysis of mutant SWI/SNF complexes and their functional consequences. Reason: Direct experimental evidence confirms SWI3's role in regulating RNA polymerase II transcription. This represents a core functional role of SWI3 in transcriptional regulation. Supporting Evidence: PMID:28249159 Composition and Function of Mutant Swi/Snf Complexes.
GO:0006338 chromatin remodeling	IDA PMID:8016655 Stimulation of GAL4 derivative binding to nucleosomal DNA by...	ACCEPT	Summary: SWI3-dependent chromatin remodeling documented through stimulation of GAL4 derivative binding to nucleosomal DNA by the yeast SWI/SNF complex. Reason: Direct experimental evidence confirms SWI3's role in chromatin remodeling. Duplicate annotation from different source (PMID:8016655) reinforces core function. Supporting Evidence: PMID:8016655 Stimulation of GAL4 derivative binding to nucleosomal DNA by the yeast SWI/SNF complex.
GO:0005829 cytosol	IDA PMID:22932476 The nuclear localization of SWI/SNF proteins is subjected to...	KEEP AS NON CORE	Summary: SWI3 is found in the cytosol, particularly under hypoxic conditions when it relocalizes from the nucleus. This represents a dynamic localization pattern dependent on oxygen availability. Reason: Cytosol localization is real and documented by experimental evidence. However, this represents a subcellular location rather than a functional annotation. The functional significance is related to oxygen-dependent regulation of respiration genes and metabolic adaptation, not simply being in the cytosol. Supporting Evidence: PMID:22932476 The nuclear localization of SWI/SNF proteins is subjected to oxygen regulation. file:yeast/SWI3/SWI3-deep-research-falcon.md over 95% of Swi3 (and several other SWI/SNF components) accumulate in the cytosol**
GO:0003677 DNA binding	IDA PMID:16461455 Structure and function of the SWIRM domain, a conserved prot...	ACCEPT	Summary: The isolated Swi3 SWIRM domain was directly shown to bind DNA in vitro by Da et al. (PMID:16461455), with apparent Kd ~72-105 nM (including ~105.36 ± 7.65 nM for cruciform DNA). Structure-guided SWIRM mutations (D374A, K383D/K387D, N392A) abolish DNA binding; these same mutations also reduce complex stability and association, so SWIRM DNA binding and complex assembly are coupled rather than mutually exclusive. Reason: This direct experimental (IDA) annotation, matching UniProt's curated SGD IDA DNA binding annotation, is the strongest evidence for SWI3 molecular function and overturns the earlier REMOVE reasoning. Falcon deep research confirms quantitative in vitro DNA binding by the SWIRM domain, and UniProt annotates the corresponding SWIRM residues as "Loss of DNA-binding". This is a core informative molecular function for SWI3. Supporting Evidence: PMID:16461455 Structure and function of the SWIRM domain, a conserved protein module found in chromatin regulatory complexes. file:yeast/SWI3/SWI3-deep-research-falcon.md Swi3 SWIRM cruciform DNA binding KD ~105.36 ± 7.65 nM, with other apparent binding estimates in the ~72–90 nM range.
GO:0003677 DNA binding	IMP PMID:16461455 Structure and function of the SWIRM domain, a conserved prot...	ACCEPT	Summary: SWIRM-domain point mutations (D374A, K383D/K387D, N392A) abolish DNA binding by Swi3 and produce swi/snf phenotypes, supporting that DNA binding is a functionally required activity of the SWIRM domain. UniProt annotates each of these residues with "Loss of DNA-binding" (from PMID:16461455). Reason: Mutation evidence (IMP) is consistent with direct DNA binding by the SWIRM domain rather than refuting it; the earlier REMOVE reasoning is overturned. Loss-of-DNA-binding SWIRM mutations cause functional defects, supporting a biologically relevant DNA binding activity. Falcon deep research and the UniProt MUTAGEN annotations both support this. Supporting Evidence: PMID:16461455 Structure and function of the SWIRM domain, a conserved protein module found in chromatin regulatory complexes. file:yeast/SWI3/SWI3-deep-research-falcon.md Structure-guided mutations in SWIRM (e.g., targeting residues implicated in binding or core stability) produce moderate to strong swi/snf phenotypes and can reduce Swi3 protein levels and defectively associate with SWI/SNF, as measured by coprecipitation with Swp73.
GO:0005634 nucleus	IDA PMID:1339306 Characterization of the yeast SWI1, SWI2, and SWI3 genes, wh...	KEEP AS NON CORE	Summary: SWI3 nuclear localization documented in the original characterization of SWI genes. SWI3 is predominantly nuclear as part of the SWI/SNF complex. Reason: Nuclear localization is documented and accurate, but represents a cellular location characteristic rather than functional annotation. See also duplicate annotations (PMID:22932476) and dynamic regulation under hypoxia. Supporting Evidence: PMID:1339306 Characterization of the yeast SWI1, SWI2, and SWI3 genes, which encode a global activator of transcription.
GO:0005634 nucleus	IDA PMID:22932476 The nuclear localization of SWI/SNF proteins is subjected to...	KEEP AS NON CORE	Summary: SWI3 nuclear localization confirmed through experimental evidence showing oxygen-dependent regulation of nuclear localization. Under normal aerobic conditions, SWI3 is nuclear; under hypoxia, it relocates to the cytosol. Reason: Nuclear localization is documented but represents a cellular location rather than functional annotation. Duplicate annotation; see oxygen-regulated localization in PMID:22932476. Supporting Evidence: PMID:22932476 The nuclear localization of SWI/SNF proteins is subjected to oxygen regulation.
GO:0016514 SWI/SNF complex	IDA PMID:18644858 Architecture of the SWI/SNF-nucleosome complex	ACCEPT	Summary: SWI3 is part of SWI/SNF complex documented through direct experimental analysis of complex architecture using cryo-EM and structural studies. Reason: Direct experimental evidence confirms SWI3 is a component of the SWI/SNF complex. This is a core cellular component annotation. Duplicate from different source reinforces finding. Cryo-EM of the yeast Swi/Snf complex (Wang et al. 2020) further resolves two copies of Swi3 (Swi3A/Swi3B) whose SWIRM domains contact the Snf5 RPT regions. Supporting Evidence: PMID:18644858 Jul 21. Architecture of the SWI/SNF-nucleosome complex. PMID:32636384 interact with the SWIRM domains of Swi3A and Swi3B by electrostatic interaction file:yeast/SWI3/SWI3-deep-research-falcon.md Swi3 SWIRM domains contact Snf5 RPT regions (electrostatic interactions) within the SWI/SNF base module
GO:0016514 SWI/SNF complex	IDA PMID:8016655 Stimulation of GAL4 derivative binding to nucleosomal DNA by...	ACCEPT	Summary: SWI3 component of SWI/SNF complex documented through biochemical studies of complex stimulation of transcription factor binding to nucleosomal DNA. Reason: Direct experimental evidence from functional studies confirms SWI3 is a component of the SWI/SNF complex. Duplicate annotation from independent source. Supporting Evidence: PMID:8016655 Stimulation of GAL4 derivative binding to nucleosomal DNA by the yeast SWI/SNF complex.
GO:0016514 SWI/SNF complex	IDA PMID:8127913 A multisubunit complex containing the SWI1/ADR6, SWI2/SNF2, ...	ACCEPT	Summary: SWI3 isolated as component of multisubunit SWI/SNF complex in original complex purification studies. Reason: Direct experimental evidence from original SWI/SNF complex isolation confirms SWI3 is a core component. Foundational evidence for complex membership. Supporting Evidence: PMID:8127913 A multisubunit complex containing the SWI1/ADR6, SWI2/SNF2, SWI3, SNF5, and SNF6 gene products isolated from yeast.
GO:0016514 SWI/SNF complex	IDA PMID:8159677 Five SWI/SNF gene products are components of a large multisu...	ACCEPT	Summary: SWI3 identified as component of large multisubunit complex required for transcriptional enhancement through direct isolation and characterization. Reason: Direct experimental evidence confirms SWI3 is a component of the SWI/SNF complex from independent complex purification studies. Supporting Evidence: PMID:8159677 Five SWI/SNF gene products are components of a large multisubunit complex required for transcriptional enhancement.
GO:0016514 SWI/SNF complex	IMP PMID:8159677 Five SWI/SNF gene products are components of a large multisu...	ACCEPT	Summary: SWI3 function in SWI/SNF complex documented through mutation analysis showing that swi3 mutations cause loss of transcriptional enhancement activity. Reason: Mutation evidence (IMP) confirms SWI3 is required for SWI/SNF complex function. Loss of SWI3 function abolishes complex-dependent transcriptional enhancement. Supporting Evidence: PMID:8159677 Five SWI/SNF gene products are components of a large multisubunit complex required for transcriptional enhancement.
GO:0031496 positive regulation of mating type switching	IMP PMID:6436497 Five SWI genes are required for expression of the HO gene in...	ACCEPT	Summary: SWI3 is required for expression of the HO endonuclease gene and mating type switching through SWI/SNF-dependent chromatin remodeling at the HO promoter. Mutation analysis shows swi3 mutants are defective in mating type switching. Reason: Direct mutation evidence (IMP) demonstrates that SWI3 is required for mating type switching through HO gene transcriptional regulation. This was the original phenotype that led to SWI3 identification. The annotation is specific and well-supported. Supporting Evidence: PMID:6436497 Five SWI genes are required for expression of the HO gene in yeast.
GO:0042393 histone binding	IPI PMID:17496903 Swi3p controls SWI/SNF assembly and ATP-dependent H2A-H2B di...	ACCEPT	Summary: SWI3 histone binding documented through protein-protein interaction studies. SWI3 interacts with histones H2A, H2B, H3, and H4 as part of nucleosome remodeling mechanism. Reason: SWI3 demonstrates histone binding through biochemical evidence (IPI). This binding is functional for nucleosome engagement. The interaction is mediated through protein-protein contacts with histone tails, particularly with acetylated forms. Supporting Evidence: PMID:17496903 May 13. Swi3p controls SWI/SNF assembly and ATP-dependent H2A-H2B displacement.
GO:0045944 positive regulation of transcription by RNA polymerase II	IMP PMID:1339306 Characterization of the yeast SWI1, SWI2, and SWI3 genes, wh...	ACCEPT	Summary: SWI3 is required for positive regulation of transcription by RNA polymerase II as demonstrated through genetic analysis of swi3 mutants showing defective transcriptional activation. Reason: Mutation evidence demonstrates that SWI3 is required for RNA polymerase II-dependent transcriptional activation. From original SWI3 characterization paper showing swi3 mutants have defective transcription of multiple genes. Supporting Evidence: PMID:1339306 Characterization of the yeast SWI1, SWI2, and SWI3 genes, which encode a global activator of transcription.
GO:0045944 positive regulation of transcription by RNA polymerase II	IMP PMID:3542227 Cell cycle control of the yeast HO gene cis and trans-acting...	ACCEPT	Summary: SWI3 is required for positive regulation of transcription by RNA polymerase II at cell cycle-controlled genes, as shown through analysis of the HO gene regulation during cell cycle. Reason: Mutation evidence demonstrates SWI3's role in cell cycle-dependent transcriptional activation. SWI3 is required for proper cell cycle regulation of HO and other genes. Supporting Evidence: PMID:3542227 Cell cycle control of the yeast HO gene: cis- and trans-acting regulators.