| Evidence theme | Key findings | Key experimental approach | Representative citations with publication year + URL |
|---|---|---|---|
| Identity / complex membership | SWI3 in *Saccharomyces cerevisiae* corresponds to YJL176C and is a defined subunit of the Swi/Snf chromatin-remodeling complex required for transcriptional control of many yeast genes; literature also distinguishes Swi3 from the paralog/homolog Swh3 that functions with Sth1 in an essential Swi/Snf-related complex rather than canonical Swi/Snf. (pqac-00000003, pqac-00000013) | Biochemical purification/immunoblotting of Swi/Snf complex; genetic and two-hybrid analyses distinguishing Swi3 vs. Swh3 complexes. (pqac-00000000, pqac-00000003) | Cairns et al., 1996, *Mol Cell Biol* / https://doi.org/10.1128/mcb.16.7.3308; Treich & Carlson, 1997, *Mol Cell Biol* / https://doi.org/10.1128/mcb.17.4.1768 |
| Domains | Swi3 contains a SWIRM domain with direct nucleic-acid binding activity and also carries SANT and leucine-zipper/coiled-coil features noted in structural and genetic studies; SWIRM mutations impair protein stability, complex association, and growth-related Swi/Snf phenotypes. GST-Swi3 SWIRM bound cruciform DNA with reported Kd ~105.36 ± 7.65 nM; apparent nucleic-acid binding was also reported in the ~72–90 nM range for the isolated domain. (pqac-00000006, pqac-00000008) | SWIRM domain structure determination plus in vitro DNA-binding assays and structure-guided mutagenesis; mutant growth and co-precipitation assays. (pqac-00000006, pqac-00000008) | Da et al., 2006, *PNAS* / https://doi.org/10.1073/pnas.0510949103; Wang et al., 2020, *Nat Commun* / https://doi.org/10.1038/s41467-020-17229-x |
| Structure / assembly | Swi3 is a backbone/scaffold subunit of yeast Swi/Snf. Cryo-EM studies identify two Swi3 copies (Swi3A/Swi3B) in the base module; Swi3 SWIRM domains contact Snf5 RPT regions, SANT elements contribute to architecture, and Swi3 helps form the outer frame with Snf12. Earlier genetic work showed Swi3 interacts with Snf2 and that the leucine-zipper motif is functionally required. (pqac-00000007, pqac-00000002, pqac-00000014) | Cryo-EM structural analysis of purified Swi/Snf; yeast two-hybrid interaction mapping; functional mutational analysis of Swi3 motifs. (pqac-00000007, pqac-00000002) | Wang et al., 2020, *Nat Commun* / https://doi.org/10.1038/s41467-020-17229-x; Treich & Carlson, 1997, *Mol Cell Biol* / https://doi.org/10.1128/mcb.17.4.1768 |
| Transcriptional roles | Swi3 functions within Swi/Snf to remodel nucleosomes and support transcriptional regulation. Canonical Swi/Snf facilitates transcriptional activation, and tethering assays linked Swi3-containing complexes to activation. Recent work also supports a repressive role at selected proximal promoters: the swi3-E815X allele reduces Swi/Snf-mediated repression at some LUTI-associated TSSs, though more mildly than snf2-W935R. (pqac-00000003, pqac-00000002, pqac-00000005) | Reporter/tethering assays, two-hybrid assays, and recent transcript-isoform analysis of transcriptional interference targets in swi3 mutants. (pqac-00000002, pqac-00000005) | Treich & Carlson, 1997, *Mol Cell Biol* / https://doi.org/10.1128/mcb.17.4.1768; Morse et al., 2024, *Molecular Cell* / https://doi.org/10.1016/j.molcel.2024.06.029 |
| Localization | Swi3 is predominantly nuclear under normoxia but relocalizes to the cytosol under hypoxia and returns to the nucleus upon reoxygenation, indicating condition-dependent control of SWI/SNF subcellular distribution. Dastidar et al. identify Swi3 as one of six Swi/Snf proteins with this behavior. (pqac-00000009, pqac-00000010, pqac-00000012) | GFP/live-cell fluorescence imaging and nuclear import/localization time-course assays under hypoxia and reoxygenation. (pqac-00000009, pqac-00000013) | Dastidar et al., 2012, *Cell & Bioscience* / https://doi.org/10.1186/2045-3701-2-30 |
| Quantitative data | Representative quantitative findings include: isolated Swi3 SWIRM domain DNA binding Kd ~105.36 ± 7.65 nM and ~72–90 nM in related assays; LexA-Swh3 activity was ~25-fold lower than LexA-Snf2 in reporter assays, with standard errors <7% in similar measurements; under hypoxia, >95% of Swi3 and several other Swi/Snf proteins were cytosolic, versus predominantly nuclear in air; 112 oxygen-regulated target genes were listed for Swi3 in wild-type HAP1 cells; swi3-E815X caused significant upregulation of ODC2PROX and HNT1PROX with relatively mild genome-wide effects compared with snf2 mutants. (pqac-00000006, pqac-00000008, pqac-00000002, pqac-00000011, pqac-00000012, pqac-00000005) | Quantitative DNA-binding assays, β-gal reporter assays, fluorescence localization scoring across counted cells, and transcript/TSS profiling in mutant strains. (pqac-00000006, pqac-00000002, pqac-00000009, pqac-00000005) | Da et al., 2006, *PNAS* / https://doi.org/10.1073/pnas.0510949103; Treich & Carlson, 1997, *Mol Cell Biol* / https://doi.org/10.1128/mcb.17.4.1768; Dastidar et al., 2012, *Cell & Bioscience* / https://doi.org/10.1186/2045-3701-2-30; Morse et al., 2024, *Molecular Cell* / https://doi.org/10.1016/j.molcel.2024.06.029 |


*Table: This table summarizes experimentally supported functional annotation evidence for yeast SWI3/YJL176C (UniProt P32591), organized by identity, domains, structure, transcriptional role, localization, and quantitative findings. It is useful as a compact evidence map tied to specific primary studies and context citations.*