DNA2 and EXO1 in replication-coupled, homology-directed repair and in the interplay between HDR and the FA/BRCA network

Kenneth K Karanja, Stephanie W Cox, Julien P Duxin, Sheila A Stewart, Judith L Campbell

63 Citations (Scopus)

Abstract

During DNA replication, stalled replication forks and DSBs arise when the replication fork encounters ICLs (interstrand crosslinks), covalent protein/DNA intermediates or other discontinuities in the template. Recently, homologous recombination proteins have been shown to function in replication-coupled repair of ICLs in conjunction with the Fanconi anemia (FA) regulatory factors FANCD2-FANCI, and, conversely, the FA gene products have been shown to play roles in stalled replication fork rescue even in the absence of ICLs, suggesting a broader role for the FA network than previously appreciated. Here we show that DNA2 helicase/nuclease participates in resection during replication-coupled repair of ICLs and other replication fork stresses. DNA2 knockdowns are deficient in HDR (homology-directed repair) and the S phase checkpoint and exhibit genome instability and sensitivity to agents that cause replication stress. DNA2 is partially redundant with EXO1 in these roles. DNA2 interacts with FANCD2, and cisplatin induces FANCD2 ubiquitylation even in the absence of DNA2. DNA2 and EXO1 deficiency leads to ICL sensitivity but does not increase ICL sensitivity in the absence of FANCD2. This is the first demonstration of the redundancy of human resection nucleases in the HDR step in replication-coupled repair, and suggests that DNA2 may represent a new mediator of the interplay between HDR and the FA/BRCA pathway.

Original languageEnglish
JournalCell Cycle
Volume11
Issue number21
Pages (from-to)3983-96
Number of pages14
ISSN1538-4101
DOIs
Publication statusPublished - 1 Nov 2012
Externally publishedYes

Keywords

  • Antineoplastic Agents
  • Breast Neoplasms
  • Cell Line, Tumor
  • Cisplatin
  • DNA Damage
  • DNA Helicases
  • DNA Repair
  • DNA Repair Enzymes
  • Exodeoxyribonucleases
  • Fanconi Anemia
  • Fanconi Anemia Complementation Group D2 Protein
  • Female
  • Genomic Instability
  • HEK293 Cells
  • Humans
  • RNA Interference
  • RNA, Small Interfering
  • Ubiquitination
  • Journal Article
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

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