A novel role of the Dna2 translocase function in DNA break resection
- Adam S. Miller1,4,
- James M. Daley1,4,
- Nhung Tuyet Pham2,
- Hengyao Niu3,
- Xiaoyu Xue1,
- Grzegorz Ira2 and
- Patrick Sung1
- 1Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520, USA;
- 2Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA;
- 3Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana 47405, USA
- Corresponding authors: patrick.sung{at}yale.edu, james.daley{at}yale.edu, gira{at}bcm.edu
-
↵4 These authors contributed equally to this work.
Abstract
DNA double-strand break repair by homologous recombination entails nucleolytic resection of the 5′ strand at break ends. Dna2, a flap endonuclease with 5′–3′ helicase activity, is involved in the resection process. The Dna2 helicase activity has been implicated in Okazaki fragment processing during DNA replication but is thought to be dispensable for DNA end resection. Unexpectedly, we found a requirement for the helicase function of Dna2 in end resection in budding yeast cells lacking exonuclease 1. Biochemical analysis reveals that ATP hydrolysis-fueled translocation of Dna2 on ssDNA facilitates 5′ flap cleavage near a single-strand–double strand junction while attenuating 3′ flap incision. Accordingly, the ATP hydrolysis-defective dna2-K1080E mutant is less able to generate long products in a reconstituted resection system. Our study thus reveals a previously unrecognized role of the Dna2 translocase activity in DNA break end resection and in the imposition of the 5′ strand specificity of end resection.
Keywords
Footnotes
-
Supplemental material is available for this article.
-
Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.295659.116.
- Received December 26, 2016.
- Accepted February 17, 2017.
This article is distributed exclusively by Cold Spring Harbor Laboratory Press for the first six months after the full-issue publication date (see http://genesdev.cshlp.org/site/misc/terms.xhtml). After six months, it is available under a Creative Commons License (Attribution-NonCommercial 4.0 International), as described at http://creativecommons.org/licenses/by-nc/4.0/.