A conserved pathway to activate BRCA1-dependent ubiquitylation at DNA damage sites

EMBO J. 2006 May 17;25(10):2178-88. doi: 10.1038/sj.emboj.7601102. Epub 2006 Apr 20.

Abstract

The BRCA1 tumour suppressor and its heterodimeric partner BARD1 constitute an E3-ubiquitin (Ub) ligase and function in DNA repair by unknown mechanisms. We show here that the Caenorhabditis elegans BRCA1/BARD1 (CeBCD) complex possesses an E3-Ub ligase responsible for ubiquitylation at DNA damage sites following ionizing radiation (IR). The DNA damage checkpoint promotes the association of the CeBCD complex with E2-Ub conjugating enzyme, Ubc5(LET-70), leading to the formation of an active E3-Ub ligase on chromatin following IR. Correspondingly, defects in Ubc5(let-70) or the DNA damage checkpoint genes atl-1 or mre-11 abolish CeBCD-dependent ubiquitylation in vivo. Extending these findings to human cells reveals a requirement for UbcH5c, the MRN complex, gamma-H2AX and a co-dependence for ATM and ATR kinases for BRCA1-dependent ubiquitylation at DNA damage sites. Furthermore, we demonstrate that the DNA damage checkpoint promotes the association between BRCA1 and UbcH5c to form an active E3-Ub ligase on chromatin after IR. These data reveal that BRCA1-dependent ubiquitylation is activated at sites of DNA repair by the checkpoint as part of a conserved DNA damage response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • BRCA1 Protein / genetics
  • BRCA1 Protein / metabolism*
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cell Line
  • Chromatin / metabolism
  • DNA Damage*
  • DNA Repair
  • Enzyme Activation
  • Humans
  • Multiprotein Complexes
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Rad51 Recombinase / genetics
  • Rad51 Recombinase / metabolism
  • Signal Transduction / physiology*
  • Ubiquitin / metabolism*
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism

Substances

  • BRCA1 Protein
  • Caenorhabditis elegans Proteins
  • Chromatin
  • Multiprotein Complexes
  • RNA, Small Interfering
  • Ubiquitin
  • Ubiquitin-Protein Ligases
  • Rad51 Recombinase