The ctf13-30/CTF13 genomic haploinsufficiency modifier screen identifies the yeast chromatin remodeling complex RSC, which is required for the establishment of sister chromatid cohesion.
The budding yeast centromere-kinetochore complex ensures high-fidelity chromosome segregation in mitosis and meiosis by mediating the attachment and movement of chromosomes along spindle microtubules. To identify new genes and pathways whose function impinges on chromosome transmission, we developed a genomic haploinsufficiency modifier screen and used ctf13-30, encoding a mutant core kinetochore protein, as the reference point. We demonstrate through a series of secondary screens that the genomic modifier screen is a successful method for identifying genes that encode nonessential proteins required for the fidelity of chromosome segregation. One gene isolated in our screen was RSC2, a nonessential subunit of the RSC chromatin remodeling complex. rsc2 mutants have defects in both chromosome segregation and cohesion, but the localization of kinetochore proteins to centromeres is not affected. We determined that, in the absence of RSC2, cohesin could still associate with chromosomes but fails to achieve proper cohesion between sister chromatids, indicating that RSC has a role in the establishment of cohesion. In addition, numerous subunits of RSC were affinity purified and a new component of RSC, Rtt102, was identified. Our work indicates that only a subset of the nonessential RSC subunits function in maintaining chromosome transmission fidelity.
Baetz
Kristin K
KK
Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada V5Z 4H4.
Krogan
Nevan J
NJ
Emili
Andrew
A
Greenblatt
Jack
J
Hieter
Philip
P
D002503:Centromere / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000502:physiology; D023902:Chromosome Pairing / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D018386:Kinetochores; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D014157:Transcription Factors / Q000378:metabolism*
C081071:CBF2 protein, S cerevisiae; C092746:CSE4 protein, S cerevisiae; C081354:CTF13 protein, S cerevisiae; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; C444703:Ctf3 protein, S cerevisiae; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C103337:RSC complex, S cerevisiae; C457180:RSC2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors