title: A genetic screen for high copy number suppressors of the synthetic lethality between elg1Δ and srs2Δ in yeast.
abstract: Elg1 and Srs2 are two proteins involved in maintaining genome stability in yeast. After DNA damage, the homotrimeric clamp PCNA, which provides stability and processivity to DNA polymerases and serves as a docking platform for DNA repair enzymes, undergoes modification by the ubiquitin-like molecule SUMO. PCNA SUMOylation helps recruit Srs2 and Elg1 to the replication fork. In the absence of Elg1, both SUMOylated PCNA and Srs2 accumulate at the chromatin fraction, indicating that Elg1 is required for removing SUMOylated PCNA and Srs2 from DNA. Despite this interaction, which suggests that the two proteins work together, double mutants elg1Δ srs2Δ have severely impaired growth as haploids and exhibit synergistic sensitivity to DNA damage and a synergistic increase in gene conversion. In addition, diploid elg1Δ srs2Δ double mutants are dead, which implies that an essential function in the cell requires at least one of the two gene products for survival. To gain information about this essential function, we have carried out a high copy number suppressor screen to search for genes that, when overexpressed, suppress the synthetic lethality between elg1Δ and srs2Δ. We report the identification of 36 such genes, which are enriched for functions related to DNA- and chromatin-binding, chromatin packaging and modification, and mRNA export from the nucleus.
authors.affiliation: Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel.
authors.forename: Inbal
authors.initials: I
authors.lastname: Gazy
authors.forename: Batia
authors.initials: B
authors.lastname: Liefshitz
authors.forename: Alex
authors.initials: A
authors.lastname: Bronstein
authors.forename: Oren
authors.initials: O
authors.lastname: Parnas
authors.forename: Nir
authors.initials: N
authors.lastname: Atias
authors.forename: Roded
authors.initials: R
authors.lastname: Sharan
authors.forename: Martin
authors.initials: M
authors.lastname: Kupiec
mesh_terms: D002352:Carrier Proteins / Q000235:genetics*; D004249:DNA Damage / Q000235:genetics; D004265:DNA Helicases / Q000235:genetics*; D018628:Gene Dosage / Q000235:genetics*; D005800:Genes, Fungal / Q000235:genetics*; D016153:Genes, Suppressor; D005820:Genetic Testing; D058977:Molecular Sequence Annotation; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; C477609:Elg1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C061376:SRS2 protein, S cerevisiae; D004265:DNA Helicases