The MRE11 GAR motif regulates DNA double-strand break processing and ATR activation

Cell Res. 2012 Feb;22(2):305-20. doi: 10.1038/cr.2011.128. Epub 2011 Aug 9.

Abstract

The MRE11/RAD50/NBS1 complex is the primary sensor rapidly recruited to DNA double-strand breaks (DSBs). MRE11 is known to be arginine methylated by PRMT1 within its glycine-arginine-rich (GAR) motif. In this study, we report a mouse knock-in allele of Mre11 that substitutes the arginines with lysines in the GAR motif and generates the MRE11(RK) protein devoid of methylated arginines. The Mre11(RK/RK) mice were hypersensitive to γ-irradiation (IR) and the cells from these mice displayed cell cycle checkpoint defects and chromosome instability. Moreover, the Mre11(RK/RK) MEFs exhibited ATR/CHK1 signaling defects and impairment in the recruitment of RPA and RAD51 to the damaged sites. The M(RK)RN complex formed and localized to the sites of DNA damage and normally activated the ATM pathway in response to IR. The M(RK)RN complex exhibited exonuclease and DNA-binding defects in vitro responsible for the impaired DNA end resection and ATR activation observed in vivo in response to IR. Our findings provide genetic evidence for the critical role of the MRE11 GAR motif in DSB repair, and demonstrate a mechanistic link between post-translational modifications at the MRE11 GAR motif and DSB processing, as well as the ATR/CHK1 checkpoint signaling.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Animals
  • Ataxia Telangiectasia Mutated Proteins
  • Cell Cycle Checkpoints
  • Cell Cycle Proteins / metabolism*
  • Cells, Cultured
  • Checkpoint Kinase 1
  • Chromosomal Instability
  • DNA Breaks, Double-Stranded*
  • DNA Repair / physiology*
  • DNA Repair Enzymes / chemistry
  • DNA Repair Enzymes / metabolism*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / metabolism*
  • Enzyme Activation
  • Gamma Rays
  • Gene Knock-In Techniques
  • MRE11 Homologue Protein
  • Mice
  • Protein Kinases / metabolism
  • Protein-Serine-Threonine Kinases / metabolism*
  • Rad51 Recombinase / metabolism
  • Signal Transduction
  • Tumor Suppressor Proteins / metabolism

Substances

  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • Mre11a protein, mouse
  • Tumor Suppressor Proteins
  • Protein Kinases
  • Atr protein, mouse
  • Ataxia Telangiectasia Mutated Proteins
  • Atm protein, mouse
  • Checkpoint Kinase 1
  • Chek1 protein, mouse
  • Protein-Serine-Threonine Kinases
  • Rad51 Recombinase
  • Rad51 protein, mouse
  • MRE11 Homologue Protein
  • DNA Repair Enzymes