The histone H3 variant Cse4 specifies centromere identity in Saccharomyces cerevisiae by its incorporation into a special nucleosome positioned at CEN DNA, and promotes the assembly of the kinetochore complex required for faithful chromosome segregation. Our previous work showed that Cse4 is also associated with the partitioning locus STB of the 2 micron circle- a multi-copy plasmid that resides in the yeast nucleus and propagates itself stably. Cse4 is essential for the functional assembly of the plasmid partitioning complex, including the recruitment of the yeast cohesin complex at STB. We have delineated Cse4 association strictly to the origin-proximal sub-region of STB. Three of the five directly repeated tandem copies of a 62 bp consensus sequence element comprising this region are necessary and sufficient for recruitment of Cse4. Cse4-STB association is dependent on Scm3, the loading factor responsible for Cse4 incorporation into the CEN nucleosome. A chromosomally integrated copy of STB confers on the integration site the capacity for Cse4 association as well as cohesin assembly. Cse4 localization in micrococcal nuclease digested chromatin is consistent with the potential assembly of one Cse4 containing nucleosome, but not more than two, at STB. The remarkable ability of STB to acquire a very specialized, and strictly regulated, chromosome segregation factor suggests its plausible evolutionary kinship with CEN.
|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||Annotation Extension||Reference|
|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||Assay||Construct||Conditions||Strain Background||Reference|