Characterization of a novel chromatin associated protein, Cmr1, in Saccharomyces cerevisiae

초록

In order to identify novel genes involved in DNA metabolism, we analyzed the proteins that were eluted from single-stranded DNA cellulose column. The fractions contained some uncharacterized proteins including CMR1. We found that the deletion of CMR1 gene suppress the lethality of mutations of the essential S phase checkpoint genes, RAD53 and LCD1. We also found that the CMR1-deletion mutant cells were resistant to the inhibitors of DNA metabolism such as hydroxyurea, MMS, and nocodazole. The mutant cells also showed a significantly faster growth rate at low temperature (16oC) than were observed in the wild-type cells. In order to find the interaction partner of Cmr1, we purified native protein complex containing Cmr1 using tandem affinity purification method. Cmr1 was co-purified with FACT complex, histone proteins, and repair proteins Msh6 and Rev7. Consistent with this result, we found that Cmr1 protein associated with chromatin in G1 phase and cmr1 mutation increased the rate of spontaneous mutation by two-fold. Our results indicate that Cmr1 may be involved in transcriptional regulation or DNA metabolism.