DNA in eukaryotic cells is packed in tandem repeats of nucleosomes or higher-order chromatin structures, which present obstacles to many cellular processes that require protein-DNA interactions, such as transcription, DNA repair, and recombination. To find proteins that are involved in increasing the accessibility of specific DNA regions in yeast, we used a genetic approach that exploited transcriptional silencing normally occurring at HML and HMR loci. The silencing is mediated by cis-acting silencer elements and is thought to require the formation of a special chromatin structure that prevents accessibility to the silenced DNA. A previously uncharacterized gene, termed DIS1, was isolated from a screen for genes that interfere with silencing when overexpressed. DIS1 encodes a protein with conserved motifs that are present in a family of DNA-dependent ATPases, the SWI2/SNF2-like proteins. Overproduction of N-terminal half of DIS1 protein interfered specifically with ectopic silencing used in the screen as well as HMR E silencing. Two-hybrid studies revealed a specific interaction between the N terminus of DIS1 and the C-terminal half of SIR4, a protein essential for silencing. Cells with a dis1 knockout mutation had significantly lower mating-type switching rate. These results suggest that DIS1 may contribute to making the silenced DNA template at HM loci more accessible during the mating-type switching process.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|