Mre11 Protein Complex Prevents Double-Strand Break Accumulation During Chromosomal DNA Replication

Mol Cell. 2001 Jul;8(1):137-47. doi: 10.1016/s1097-2765(01)00294-5.

Abstract

Mre11 complex promotes repair of DNA double-strand breaks (DSBs). Xenopus Mre11 (X-Mre11) has been cloned, and its role in DNA replication and DNA damage checkpoint studied in cell-free extracts. DSBs stimulate the phosphorylation and 3'-5' exonuclease activity of X-Mre11 complex. This induced phosphorylation is ATM independent. Phosphorylated X-Mre11 is found associated with replicating nuclei. X-Mre11 complex is required to yield normal DNA replication products. Genomic DNA replicated in extracts immunodepleted of X-Mre11 complex accumulates DSBs as demonstrated by TUNEL assay and reactivity to phosphorylated histone H2AX antibodies. In contrast, the ATM-dependent DNA damage checkpoint that blocks DNA replication initiation is X-Mre11 independent. These results strongly suggest that the function of X-Mre11 complex is to repair DSBs that arise during normal DNA replication, thus unraveling a critical link between recombination-dependent repair and DNA replication.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antifungal Agents / pharmacology
  • Caffeine / pharmacology
  • Cell Cycle / physiology*
  • Cell Nucleus / metabolism
  • Cell-Free System
  • Chromatin / metabolism
  • DNA Damage*
  • DNA Repair*
  • DNA Replication*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / metabolism*
  • Humans
  • Immunoblotting
  • In Situ Nick-End Labeling
  • MRE11 Homologue Protein
  • Models, Biological
  • Molecular Sequence Data
  • Oocytes / chemistry
  • Oocytes / physiology
  • Phosphodiesterase Inhibitors / pharmacology
  • Phosphoprotein Phosphatases / antagonists & inhibitors
  • Phosphorylation
  • Protein Binding
  • Pyrans*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Spiro Compounds*
  • Xenopus laevis / genetics
  • Xenopus laevis / physiology

Substances

  • Antifungal Agents
  • Chromatin
  • DNA-Binding Proteins
  • MRE11 protein, human
  • Phosphodiesterase Inhibitors
  • Pyrans
  • Recombinant Proteins
  • Spiro Compounds
  • tautomycin
  • Caffeine
  • MRE11 Homologue Protein
  • Phosphoprotein Phosphatases