The centromere-specific histone variant Cse4p (CENP-A) is essential for functional chromatin architecture at the yeast 2-microm circle partitioning locus and promotes equal plasmid segregation.
The centromere protein A homologue Cse4p is required for kinetochore assembly and faithful chromosome segregation in Saccharomyces cerevisiae. It has been regarded as the exquisite hallmark of centromeric chromatin. We demonstrate that Cse4 resides at the partitioning locus STB of the 2-microm plasmid. Cse4p-STB association is absolutely dependent on the plasmid partitioning proteins Rep1p and Rep2p and the integrity of the mitotic spindle. The kinetochore mutation ndc10-1 excludes Cse4p from centromeres without dislodging it from STB. Cse4p-STB association lasts from G1/S through late telophase during the cell cycle. The release of Cse4p from STB chromatin is likely mediated through spindle disassembly. A lack of functional Cse4p disrupts the remodeling of STB chromatin by the RSC2 complex, negates Rep2p binding and cohesin assembly at STB, and causes plasmid missegregation. Poaching of a specific histone variant by the plasmid to mark its partitioning locus with a centromere tag reveals yet another one of the molecular trickeries it performs for achieving chromosome- like fidelity in segregation.
Hajra
Sujata
S
Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, TX 78712, USA.
Ghosh
Santanu Kumar
SK
Jayaram
Makkuni
M
D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000502:physiology; D002503:Centromere / Q000235:genetics / Q000378:metabolism*; D002843:Chromatin / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D020090:Chromosome Segregation / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018816:Genes, cdc / Q000502:physiology; D018386:Kinetochores / Q000378:metabolism / Q000648:ultrastructure; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000378:metabolism; D010957:Plasmids / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D000097722:Cohesins
D018797:Cell Cycle Proteins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D000097722:Cohesins; C092746:CSE4 protein, S cerevisiae; C491137:REP1 protein, S cerevisiae; C490689:REP2 protein, S cerevisiae; C457180:RSC2 protein, S cerevisiae