RPA-Mediated Recruitment of the E3 Ligase RFWD3 Is Vital for Interstrand Crosslink Repair and Human Health

Mol Cell. 2017 Jun 1;66(5):610-621.e4. doi: 10.1016/j.molcel.2017.04.021.

Abstract

Defects in the repair of DNA interstrand crosslinks (ICLs) are associated with the genome instability syndrome Fanconi anemia (FA). Here we report that cells with mutations in RFWD3, an E3 ubiquitin ligase that interacts with and ubiquitylates replication protein A (RPA), show profound defects in ICL repair. An amino acid substitution in the WD40 repeats of RFWD3 (I639K) found in a new FA subtype abolishes interaction of RFWD3 with RPA, thereby preventing RFWD3 recruitment to sites of ICL-induced replication fork stalling. Moreover, single point mutations in the RPA32 subunit of RPA that abolish interaction with RFWD3 also inhibit ICL repair, demonstrating that RPA-mediated RFWD3 recruitment to stalled replication forks is important for ICL repair. We also report that unloading of RPA from sites of ICL induction is perturbed in RFWD3-deficient cells. These data reveal important roles for RFWD3 localization in protecting genome stability and preserving human health.

Keywords: Fanconi anemia; RFWD3; RPA; homologous recombination; interstrand crosslink; ubiquitylation.

MeSH terms

  • Binding Sites
  • DNA Damage*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Endonucleases / genetics
  • Endonucleases / metabolism
  • Fanconi Anemia / enzymology*
  • Fanconi Anemia / genetics
  • HeLa Cells
  • Humans
  • Mutation
  • Protein Binding
  • RNA Interference
  • Recombinational DNA Repair*
  • Replication Origin*
  • Replication Protein A / genetics
  • Replication Protein A / metabolism*
  • Transfection
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism*

Substances

  • DNA-Binding Proteins
  • Replication Protein A
  • RFWD3 protein, human
  • Ubiquitin-Protein Ligases
  • RPA2 protein, human
  • ERCC1 protein, human
  • Endonucleases