Genetic and biochemical evidences reveal novel insights into the mechanism underlying Saccharomyces cerevisiae Sae2-mediated abrogation of DNA replication stress

Ghodke, Indrajeet and Muniyappa, K (2016) Genetic and biochemical evidences reveal novel insights into the mechanism underlying Saccharomyces cerevisiae Sae2-mediated abrogation of DNA replication stress. In: JOURNAL OF BIOSCIENCES, 41 (4). pp. 615-641.

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Abstract

In Saccharomyces cerevisiae, the Mre11-Rad50-Xrs2 (MRX) protein complex plays pivotal roles in double-strand break (DSB) repair, replication stress and telomere length maintenance. Another protein linked to DSB repair is Sae2, which regulates MRX persistence at DSBs. However, very little is known about its role in DNA replication stress and repair. Here, we reveal a crucial role for Sae2 in DNA replication stress. We show that different mutant alleles of SAE2 cause hypersensitivity to genotoxic agents, and when combined with Delta mre11 or nuclease-defective mre11 mutant alleles, the double mutants are considerably more sensitive suggesting that the sae2 mutations synergize with mre11 mutations. Biochemical studies demonstrate that Sae2 exists as a dimer in solution, associates preferentially with single-stranded and branched DNA structures, exhibits structure-specific endonuclease activity and cleaves these substrates from the 5' end. Furthermore, we show that the nuclease activity is indeed intrinsic to Sae2. Interestingly, sae2(G270D) protein possesses DNA-binding activity, but lacks detectable nuclease activity. Altogether, our data suggest a direct role for Sae2 nuclease activity in processing of the DNA structures that arise during replication and DNA damage and provide insights into the mechanism underlying Mre11-Sae2-mediated abrogation of replication stress-related defects in S. cerevisiae.

Item Type:	Journal Article
Publication:	JOURNAL OF BIOSCIENCES
Additional Information:	Copy right for this article belongs to theINDIAN ACAD SCIENCES, C V RAMAN AVENUE, SADASHIVANAGAR, P B #8005, BANGALORE 560 080, INDIA
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	31 Jan 2017 04:34
Last Modified:	31 Jan 2017 04:34
URI:	http://eprints.iisc.ac.in/id/eprint/55972

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