Mammalian RAD52 Functions in Break-Induced Replication Repair of Collapsed DNA Replication Forks

Mol Cell. 2016 Dec 15;64(6):1127-1134. doi: 10.1016/j.molcel.2016.10.038.

Abstract

Human cancers are characterized by the presence of oncogene-induced DNA replication stress (DRS), making them dependent on repair pathways such as break-induced replication (BIR) for damaged DNA replication forks. To better understand BIR, we performed a targeted siRNA screen for genes whose depletion inhibited G1 to S phase progression when oncogenic cyclin E was overexpressed. RAD52, a gene dispensable for normal development in mice, was among the top hits. In cells in which fork collapse was induced by oncogenes or chemicals, the Rad52 protein localized to DRS foci. Depletion of Rad52 by siRNA or knockout of the gene by CRISPR/Cas9 compromised restart of collapsed forks and led to DNA damage in cells experiencing DRS. Furthermore, in cancer-prone, heterozygous APC mutant mice, homozygous deletion of the Rad52 gene suppressed tumor growth and prolonged lifespan. We therefore propose that mammalian RAD52 facilitates repair of collapsed DNA replication forks in cancer cells.

Keywords: DNA recombination; DNA replication stress; RAD52; break-induced replication; cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenomatous Polyposis Coli Protein / deficiency
  • Adenomatous Polyposis Coli Protein / genetics*
  • Animals
  • CRISPR-Cas Systems
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cyclin E / genetics*
  • Cyclin E / metabolism
  • DNA / genetics*
  • DNA / metabolism
  • DNA Breaks, Double-Stranded*
  • G1 Phase
  • Gene Expression
  • Genomic Instability
  • Humans
  • Mice
  • Mice, Knockout
  • Nocodazole / pharmacology
  • Osteosarcoma / genetics*
  • Osteosarcoma / metabolism
  • Osteosarcoma / mortality
  • Osteosarcoma / pathology
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Rad52 DNA Repair and Recombination Protein / antagonists & inhibitors
  • Rad52 DNA Repair and Recombination Protein / genetics*
  • Rad52 DNA Repair and Recombination Protein / metabolism
  • Recombinational DNA Repair*
  • S Phase
  • Stress, Physiological
  • Survival Analysis

Substances

  • Adenomatous Polyposis Coli Protein
  • Cyclin E
  • RNA, Small Interfering
  • Rad52 DNA Repair and Recombination Protein
  • Rad52 protein, mouse
  • adenomatous polyposis coli protein, mouse
  • DNA
  • Nocodazole