BRCA1 Is Required for Maintenance of Phospho-Chk1 and G2/M Arrest during DNA Cross-Link Repair in DT40 Cells.
The Fanconi anemia DNA repair pathway is pivotal for the efficient repair of DNA interstrand cross-links. Here, we show that FA-defective (Fancc(-)) DT40 cells arrest in G2 phase following cross-link damage and trigger apoptosis. Strikingly, cell death was reduced in Fancc(-) cells by additional deletion of the BRCA1 tumor suppressor, resulting in elevated clonogenic survival. Increased resistance to cross-link damage was not due to loss of toxic BRCA1-mediated homologous recombination but rather through the loss of a G2 checkpoint. This proapoptotic role also required the BRCA1-A complex member ABRAXAS (FAM175A). Finally, we show that BRCA1 promotes G2 arrest and cell death by prolonging phosphorylation of Chk1 on serine 345 after DNA damage to sustain arrest. Our data imply that DNA-induced cross-link death in cells defective in the FA pathway is dependent on the ability of BRCA1 to prolong cell cycle arrest in G2 phase.
Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, Dundee, Scotland Institute of Anatomy II, Department of Vertebrate Embryology, University of Cologne, Cologne, Germany.
Margarethe
M
Draga
MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom.
Elizabeth B
EB
Madgett
MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom.
Cassandra J
CJ
Vandenberg
MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom.
David
D
du Plessis
Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, Dundee, Scotland.
Aisling
A
Kaufmann
Genome Stability Laboratory, Centre for Chromosome Biology, School of Natural Science, National University of Ireland, Galway, Ireland.
Petra
P
Werler
Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, Dundee, Scotland.
Prasun
P
Chakraborty
Genome Stability Laboratory, Centre for Chromosome Biology, School of Natural Science, National University of Ireland, Galway, Ireland.
Noel F
NF
Lowndes
Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, Dundee, Scotland MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom k.hiom@dundee.ac.uk.
Kevin
K
Hiom
D000818:Animals; D017209:Apoptosis; D030161:Avian Proteins / Q000235:genetics / Q000378:metabolism*; D019313:BRCA1 Protein / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D000071877:Checkpoint Kinase 1; D002645:Chickens; D004260:DNA Repair; D005199:Fanconi Anemia / Q000235:genetics / Q000378:metabolism; D052218:Fanconi Anemia Complementation Group C Protein / Q000235:genetics / Q000378:metabolism; D059565:G2 Phase Cell Cycle Checkpoints; D017353:Gene Deletion; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*
D030161:Avian Proteins; D019313:BRCA1 Protein; C432045:BRCA1 protein, chicken; D002352:Carrier Proteins; D052218:Fanconi Anemia Complementation Group C Protein; D011494:Protein Kinases; D000071877:Checkpoint Kinase 1