title: Temporal sequence and cell cycle cues in the assembly of host factors at the yeast 2 micron plasmid partitioning locus.
abstract: The Saccharomyces cerevisiae 2 micron plasmid exemplifies a benign but selfish genome, whose stability approaches that of the chromosomes of its host. The plasmid partitioning locus STB (stability locus) displays certain functional analogies with centromeres along with critical distinctions, a significant one being the absence of the kinetochore complex at STB. The remodels the structure of chromatin (RSC) chromatin remodeling complex, the nuclear motor Kip1, the histone H3 variant Cse4 and the cohesin complex associate with both loci. These factors appear to contribute to plasmid segregation either directly or indirectly through their roles in chromosome segregation. Assembly and disassembly of the plasmid-coded partitioning proteins Rep1 and Rep2 and host factors at STB follow a temporal hierarchy during the cell cycle. Assembly is initiated by STB association of [Rsc8-Rsc58], followed by [Rep1-Rep2-Kip1] and [Cse4-Rsc2-Sth1] recruitment, and culminates in cohesin assembly. Disassembly starts with dissociation of RSC components, is followed by cohesin disassembly and Cse4 exit during anaphase and late telophase, respectively. [Rep1-Rep2-Kip1] persists through G1 of the ensuing cell cycle. The de novo assembly of the 'partitioning complex' is cued by the innate cell cycle clock and is dependent on DNA replication. Shared functional attributes of STB and centromere (CEN) are consistent with a potential evolutionary link between them.
authors.affiliation: Section of Molecular Genetics & Microbiology, University of Texas at Austin, Austin, TX 78712, USA.
authors.forename: Chien-Hui
authors.initials: CH
authors.lastname: Ma
authors.forename: Hong
authors.initials: H
authors.lastname: Cui
authors.forename: Sujata
authors.initials: S
authors.lastname: Hajra
authors.forename: Paul A
authors.initials: PA
authors.lastname: Rowley
authors.forename: Christie
authors.initials: C
authors.lastname: Fekete
authors.forename: Ali
authors.initials: A
authors.lastname: Sarkeshik
authors.forename: Santanu Kumar
authors.initials: SK
authors.lastname: Ghosh
authors.forename: John R
authors.initials: JR
authors.lastname: Yates
authors.forename: Makkuni
authors.initials: M
authors.lastname: Jayaram
mesh_terms: D002453:Cell Cycle / Q000235:genetics*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D056426:Genetic Loci; D010957:Plasmids / Q000235:genetics*; D021122:Protein Subunits / Q000037:antagonists & inhibitors; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D021122:Protein Subunits; C491137:REP1 protein, S cerevisiae; C490689:REP2 protein, S cerevisiae; C103337:RSC complex, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors