The 2 micron plasmid purloins the yeast cohesin complex: a mechanism for coupling plasmid partitioning and chromosome segregation?
The yeast 2 micron plasmid achieves high fidelity segregation by coupling its partitioning pathway to that of the chromosomes. Mutations affecting distinct steps of chromosome segregation cause the plasmid to missegregate in tandem with the chromosomes. In the absence of the plasmid stability system, consisting of the Rep1 and Rep2 proteins and the STB DNA, plasmid and chromosome segregations are uncoupled. The Rep proteins, acting in concert, recruit the yeast cohesin complex to the STB locus. The periodicity of cohesin association and dissociation is nearly identical for the plasmid and the chromosomes. The timely disassembly of cohesin is a prerequisite for plasmid segregation. Cohesin-mediated pairing and unpairing likely provides a counting mechanism for evenly partitioning plasmids either in association with or independently of the chromosomes.
Mehta
Shwetal
S
Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, TX 78712, USA.
Yang
Xian Mei
XM
Chan
Clarence S
CS
Dobson
Melanie J
MJ
Jayaram
Makkuni
M
Velmurugan
Soundarapandian
S
D001426:Bacterial Proteins / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000378:metabolism; D002842:Chromatids / Q000235:genetics / Q000502:physiology; D002868:Chromosomal Proteins, Non-Histone; D020090:Chromosome Segregation / Q000235:genetics*; D002875:Chromosomes / Q000235:genetics*; D004271:DNA, Fungal / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D016193:G1 Phase / Q000502:physiology; D018386:Kinetochores / Q000502:physiology; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism*; D010750:Phosphoproteins; D010957:Plasmids / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators / Q000378:metabolism; D000097722:Cohesins
D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D000097722:Cohesins; C490529:MCD1 protein, S cerevisiae; C051237:REP protein, yeast plasmid; C490689:REP2 protein, S cerevisiae; C118650:SMC protein, Bacteria