Role of polycomb group proteins in the DNA damage response--a reassessment

PLoS One. 2014 Jul 24;9(7):e102968. doi: 10.1371/journal.pone.0102968. eCollection 2014.

Abstract

A growing body of evidence suggests that Polycomb group (PcG) proteins, key regulators of lineage specific gene expression, also participate in the repair of DNA double-strand breaks (DSBs) but evidence for direct recruitment of PcG proteins at specific breaks remains limited. Here we explore the association of Polycomb repressive complex 1 (PRC1) components with DSBs generated by inducible expression of the AsiSI restriction enzyme in normal human fibroblasts. Based on immunofluorescent staining, the co-localization of PRC1 proteins with components of the DNA damage response (DDR) in these primary cells is unconvincing. Moreover, using chromatin immunoprecipitation and deep sequencing (ChIP-seq), which detects PRC1 proteins at common sites throughout the genome, we did not find evidence for recruitment of PRC1 components to AsiSI-induced DSBs. In contrast, the S2056 phosphorylated form of DNA-PKcs and other DDR proteins were detected at a subset of AsiSI sites that are predominantly at the 5' ends of transcriptionally active genes. Our data question the idea that PcG protein recruitment provides a link between DSB repairs and transcriptional repression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatin / chemistry
  • Chromatin / metabolism
  • Chromatin Immunoprecipitation
  • DNA Breaks, Double-Stranded*
  • DNA Repair*
  • DNA Restriction Enzymes / genetics
  • DNA Restriction Enzymes / metabolism
  • DNA-Activated Protein Kinase / genetics*
  • DNA-Activated Protein Kinase / metabolism
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Gene Expression Regulation*
  • Histones / genetics
  • Histones / metabolism
  • Humans
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Phosphorylation
  • Polycomb Repressive Complex 1 / genetics*
  • Polycomb Repressive Complex 1 / metabolism
  • Primary Cell Culture
  • Transgenes

Substances

  • Chromatin
  • Histones
  • Nuclear Proteins
  • Polycomb Repressive Complex 1
  • DNA-Activated Protein Kinase
  • PRKDC protein, human
  • DNA Restriction Enzymes

Associated data

  • GEO/GSE55605