The BRIP1 helicase functions independently of BRCA1 in the Fanconi anemia pathway for DNA crosslink repair.
BRIP1 (also called BACH1) is a DEAH helicase that interacts with the BRCT domain of BRCA1 (refs. 1-6) and has an important role in BRCA1-dependent DNA repair and checkpoint functions. We cloned the chicken ortholog of BRIP1 and established a homozygous knockout in the avian B-cell line DT40. The phenotype of these brip1 mutant cells in response to DNA damage differs from that of brca1 mutant cells and more closely resembles that of fancc mutant cells, with a profound sensitivity to the DNA-crosslinking agent cisplatin and acute cell-cycle arrest in late S-G2 phase. These defects are corrected by expression of human BRIP1 lacking the BRCT-interaction domain. Moreover, in human cells exposed to mitomycin C, short interfering RNA-mediated knock-down of BRIP1 leads to a substantial increase in chromosome aberrations, a characteristic phenotype of cells derived from individuals with Fanconi anemia. Because brip1 mutant cells are proficient for ubiquitination of FANCD2 protein, our data indicate that BRIP1 has a function in the Fanconi anemia pathway that is independent of BRCA1 and downstream of FANCD2 activation.
Bridge
Wendy L
WL
Protein & Nucleic Acid Chemistry Division, MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
Vandenberg
Cassandra J
CJ
Franklin
Roger J
RJ
Hiom
Kevin
K
D000818:Animals; D019313:BRCA1 Protein / Q000378:metabolism*; D002645:Chickens; D002869:Chromosome Aberrations; D002945:Cisplatin / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry; D005199:Fanconi Anemia / Q000235:genetics* / Q000378:metabolism; D052236:Fanconi Anemia Complementation Group D2 Protein; D051856:Fanconi Anemia Complementation Group Proteins; D016195:G2 Phase / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D016685:Mitomycin / Q000494:pharmacology; D009687:Nuclear Proteins / Q000378:metabolism; D020365:RNA Helicases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D016196:S Phase / Q000187:drug effects; D015398:Signal Transduction; D025801:Ubiquitin / Q000378:metabolism
D019313:BRCA1 Protein; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; C499905:FANCD2 protein, human; D052236:Fanconi Anemia Complementation Group D2 Protein; D051856:Fanconi Anemia Complementation Group Proteins; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D025801:Ubiquitin; D016685:Mitomycin; C000618935:BRIP1 protein, human; D020365:RNA Helicases; D002945:Cisplatin