The ERCC1/XPF endonuclease is required for completion of homologous recombination at DNA replication forks stalled by inter-strand cross-links.
Both the ERCC1-XPF complex and the proteins involved in homoIogous recombination (HR) have critical roles in inter-strand cross-link (ICL) repair. Here, we report that mitomycin C-induced lesions inhibit replication fork elongation. Furthermore, mitomycin C-induced DNA double-strand breaks (DSBs) are the result of the collapse of ICL-stalled replication forks. These are not formed through replication run off, as we show that mitomycin C or cisplatin-induced DNA lesions are not incised by global genome nucleotide excision repair (GGR). We also suggest that ICL-lesion repair is initiated either by replication or transcription, as the GGR does not incise ICL-lesions. Furthermore, we report that RAD51 foci are induced by cisplatin or mitomycin C independently of ERCC1, but that mitomycin C-induced HR measured in a reporter construct is impaired in ERCC1-defective cells. These data suggest that ERCC1-XPF plays a role in completion of HR in ICL repair. We also find no additional sensitivity to cisplatin by siRNA co-depletion of XRCC3 and ERCC1, showing that the two proteins act on the same pathway to promote survival.
Al-Minawi
Ali Z
AZ
The Institute for Cancer Studies, University of Sheffield, Medical School, Sheffield S10 2RX, UK.
Lee
Yin-Fai
YF
Håkansson
Daniel
D
Johansson
Fredrik
F
Lundin
Cecilia
C
Saleh-Gohari
Nasrollah
N
Schultz
Niklas
N
Jenssen
Dag
D
Bryant
Helen E
HE
Meuth
Mark
M
Hinz
John M
JM
Helleday
Thomas
T
D000818:Animals; D002460:Cell Line; D002945:Cisplatin / Q000633:toxicity; D006224:Cricetinae; D003432:Cross-Linking Reagents / Q000633:toxicity*; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D004261:DNA Replication / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism*; D006801:Humans; D016685:Mitomycin / Q000633:toxicity; D009154:Mutation; D051135:Rad51 Recombinase / Q000235:genetics; D011995:Recombination, Genetic
D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; C095888:xeroderma pigmentosum group F protein; D016685:Mitomycin; D051135:Rad51 Recombinase; C071447:ERCC1 protein, human; D004720:Endonucleases; D002945:Cisplatin