A Genetic Screen for High Copy Number Suppressors of the Synthetic Lethality Between elg1Δ and srs2Δ in Yeast

摘要

and are two proteins involved in maintaining genome stability in yeast. After DNA damage, the homotrimeric clamp , 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. SUMOylation helps recruit and to the replication fork. In the absence of , both SUMOylated and accumulate at the chromatin fraction, indicating that is required for removing SUMOylated and from DNA. Despite this interaction, which suggests that the two proteins work together, double mutants Δ Δ have severely impaired growth as haploids and exhibit synergistic sensitivity to DNA damage and a synergistic increase in gene conversion. In addition, diploid Δ Δ 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 href="http://www.yeastgenome.org/cgi-bin/locus.fpl?dbid=S000005670" data-ga-action="click_feat_suppl" ref="reftype=extlink&article-id=3656737&issue-id=223019&journal-id=1684&FROM=Article%7CFront%20Matter&TO=External%7CLink%7CURI" target="_blank">elg1Δ and href="http://www.yeastgenome.org/cgi-bin/locus.fpl?dbid=S000003628" data-ga-action="click_feat_suppl" ref="reftype=extlink&article-id=3656737&issue-id=223019&journal-id=1684&FROM=Article%7CFront%20Matter&TO=External%7CLink%7CURI" target="_blank">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.