New tools to study DNA double-strand break repair pathway choice

PLoS One. 2013 Oct 14;8(10):e77206. doi: 10.1371/journal.pone.0077206. eCollection 2013.

Abstract

A broken DNA molecule is difficult to repair, highly mutagenic, and extremely cytotoxic. Such breaks can be repaired by homology-independent or homology-directed mechanisms. Little is known about the network that controls the repair pathway choice except that a licensing step for homology-mediated repair exists, called DNA-end resection. The choice between these two repair pathways is a key event for genomic stability maintenance, and an imbalance of the ratio is directly linked with human diseases, including cancer. Here we present novel reporters to study the balance between both repair options in human cells. In these systems, a double-strand break can be alternatively repaired by homology-independent or -dependent mechanisms, leading to the accumulation of distinct fluorescent proteins. These reporters thus allow the balance between both repair pathways to be analyzed in different experimental setups. We validated the reporters by analyzing the effect of protein downregulation of the DNA end resection and non-homologous end-joining pathways. Finally, we analyzed the role of the DNA damage response on double-strand break (DSB) repair mechanism selection. Our reporters could be used in the future to understand the roles of specific factors, whole pathways, or drugs in DSB repair pathway choice, or for genome-wide screening. Moreover, our findings can be applied to increase gene-targeting efficiency, making it a beneficial tool for a broad audience in the biological sciences.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biochemistry / methods*
  • Cell Cycle
  • Cell Line, Tumor
  • DNA Breaks, Double-Stranded*
  • DNA End-Joining Repair
  • DNA Repair*
  • Genes, Reporter
  • Humans
  • RNA, Small Interfering / metabolism
  • Reproducibility of Results

Substances

  • RNA, Small Interfering

Grants and funding

This work has been funded by a R+D+I grant from the Spanish Ministry of Economy and Competitivity (SAF2010-14877) and an European Research Council (ERC) Starting Grant (DSBRECA). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.