Identification of Novel Mediators of Efficient Non-Homologous End Joining in the Yeast Saccharomyces cerevisiae.

摘要

Non-homologous end joining (NHEJ) is an important mechanism for DNA repair. In order to identify novel genes that affect this process we use a plasmid-based screen for gene deletion mutants (a subset of the yeast gene deletion array, ∼380 genes) impaired for NHEJ efficiency in the model organism yeast, Saccharomyces cerevisiae. Our screen successfully identified known key NHEJ genes (such as MRE11), as well as factors previously linked to NHEJ (such as RSC2), supporting the usefulness of this screen. To confirm the influence of some of the identified candidate genes on NHEJ, drug sensitivity screens and chromosomal DNA damage screens based on the JKM139 yeast strain were used. Our results indicate NHEJ efficiency is impaired in deletion mutants lacking genes, including HUR1 (an uncharacterized gene), RTT109 and VPS75 (a complex which acetylates histones), BUB1, BUB2 and MAD3 (genes involved in the spindle assembly checkpoint), among others. BUB1 and BUB2 were found to influence the efficiency of NHEJ through an Anaphase-Promoting Complex mediated effect. This research can serve as the basis for a more complete understanding of the pathways and processes needed for reliable and efficient NHEJ in yeast.