The yeast Hrq1 helicase stimulates Pso2 translesion nuclease activity and thereby promotes DNA interstrand crosslink repair.

Autor:	Rogers CM; Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA., Lee CY; Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA., Parkins S; Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA., Buehler NJ; Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA., Wenzel S; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA., Martínez-Márquez F; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA., Takagi Y; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA., Myong S; Department of Biophysics, Johns Hopkins University, Baltimore, Maryland, USA., Bochman ML; Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana, USA. Electronic address: bochman@indiana.edu.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2020 Jul 03; Vol. 295 (27), pp. 8945-8957. Date of Electronic Publication: 2020 May 05.
DOI:	10.1074/jbc.RA120.013626
Abstrakt:	DNA interstrand crosslink (ICL) repair requires a complex network of DNA damage response pathways. Removal of the ICL lesions is vital, as they are physical barriers to essential DNA processes that require the separation of duplex DNA, such as replication and transcription. The Fanconi anemia (FA) pathway is the principal mechanism for ICL repair in metazoans and is coupled to DNA replication. In Saccharomyces cerevisiae , a vestigial FA pathway is present, but ICLs are predominantly repaired by a pathway involving the Pso2 nuclease, which is hypothesized to use its exonuclease activity to digest through the lesion to provide access for translesion polymerases. However, Pso2 lacks translesion nuclease activity in vitro , and mechanistic details of this pathway are lacking, especially relative to FA. We recently identified the Hrq1 helicase, a homolog of the disease-linked enzyme RecQ-like helicase 4 (RECQL4), as a component of Pso2-mediated ICL repair. Here, using genetic, biochemical, and biophysical approaches, including single-molecule FRET (smFRET)- and gel-based nuclease assays, we show that Hrq1 stimulates the Pso2 nuclease through a mechanism that requires Hrq1 catalytic activity. Importantly, Hrq1 also stimulated Pso2 translesion nuclease activity through a site-specific ICL in vitro We noted that stimulation of Pso2 nuclease activity is specific to eukaryotic RecQ4 subfamily helicases, and genetic and biochemical data suggest that Hrq1 likely interacts with Pso2 through their N-terminal domains. These results advance our understanding of FA-independent ICL repair and establish a role for the RecQ4 helicases in the repair of these detrimental DNA lesions. Competing Interests: Conflict of interest—The authors declare that they have no conflicts of interest with the contents of this article. (© 2020 Rogers et al.)
Databáze:	MEDLINE
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