TY - JOUR
T1 - Double-strand breaks induce homologous recombinational repair of interstrand cross-links via cooperation of MSH2, ERCC1-XPF, REV3, and the Fanconi anemia pathway
AU - Zhang, Nianxiang
AU - Liu, Xiuping
AU - Li, Lei
AU - Legerski, Randy
N1 - Funding Information:
This work was supported by NCI grants CA075160 and CA097175. DNA sequencing resources were supported by the Cancer Center Support (Core) Grant CA16672. We thank Frank Culajay and Jia Liu for providing technical support.
PY - 2007/11/1
Y1 - 2007/11/1
N2 - DNA interstrand cross-linking agents have been widely used in chemotherapeutic treatment of cancer. The majority of interstrand cross-links (ICLs) in mammalian cells are removed via a complex process that involves the formation of double-strand breaks at replication forks, incision of the ICL, and subsequent error-free repair by homologous recombination. How double-strand breaks effect the removal of ICLs and the downstream homologous recombination process is not clear. Here, we describe a plasmid-based recombination assay in which one copy of the CFP gene is inactivated by a site-specific psoralen ICL and can be repaired by gene conversion with a mutated homologous donor sequence. We found that the homology-dependent recombination (HDR) is inhibited by the ICL. However, when we introduced a double-strand break adjacent to the site of the ICL, the removal of the ICL was enhanced and the substrate was funneled into a HDR repair pathway. This process was not dependent on the nucleotide excision repair pathway, but did require the ERCC1-XPF endonuclease and REV3. In addition, both the Fanconi anemia pathway and the mismatch repair protein MSH2 were required for the recombinational repair processing of the ICL. These results suggest that the juxtaposition of an ICL and a DSB stimulates repair of ICLs through a process requiring components of mismatch repair, ERCC1-XPF, REV3, Fanconi anemia proteins, and homologous recombination repair factors.
AB - DNA interstrand cross-linking agents have been widely used in chemotherapeutic treatment of cancer. The majority of interstrand cross-links (ICLs) in mammalian cells are removed via a complex process that involves the formation of double-strand breaks at replication forks, incision of the ICL, and subsequent error-free repair by homologous recombination. How double-strand breaks effect the removal of ICLs and the downstream homologous recombination process is not clear. Here, we describe a plasmid-based recombination assay in which one copy of the CFP gene is inactivated by a site-specific psoralen ICL and can be repaired by gene conversion with a mutated homologous donor sequence. We found that the homology-dependent recombination (HDR) is inhibited by the ICL. However, when we introduced a double-strand break adjacent to the site of the ICL, the removal of the ICL was enhanced and the substrate was funneled into a HDR repair pathway. This process was not dependent on the nucleotide excision repair pathway, but did require the ERCC1-XPF endonuclease and REV3. In addition, both the Fanconi anemia pathway and the mismatch repair protein MSH2 were required for the recombinational repair processing of the ICL. These results suggest that the juxtaposition of an ICL and a DSB stimulates repair of ICLs through a process requiring components of mismatch repair, ERCC1-XPF, REV3, Fanconi anemia proteins, and homologous recombination repair factors.
KW - Homologous recombination
KW - Interstrand cross-links
KW - Mismatch repair
KW - Translesion bypass
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U2 - 10.1016/j.dnarep.2007.06.002
DO - 10.1016/j.dnarep.2007.06.002
M3 - Article
C2 - 17669695
AN - SCOPUS:35348946359
SN - 1568-7864
VL - 6
SP - 1670
EP - 1678
JO - DNA Repair
JF - DNA Repair
IS - 11
ER -