FANCM of the Fanconi anemia core complex is required for both monoubiquitination and DNA repair.
In response to DNA damage, the Fanconi anemia (FA) core complex functions as a signaling machine for monoubiquitination of FANCD2 and FANCI. It remains unclear whether this complex can also participate in subsequent DNA repair. We have shown previously that the FANCM constituent of the complex contains a highly conserved helicase domain and an associated ATP-dependent DNA translocase activity. Here we show that FANCM also possesses an ATP-independent binding activity and an ATP-dependent bi-directional branch-point translocation activity on a synthetic four-way junction DNA, which mimics intermediates generated during homologous recombination or at stalled replication forks. Using an siRNA-based complementation system, we found that the ATP-dependent activities of FANCM are required for cellular resistance to a DNA-crosslinking drug, mitomycin C, but not for the monoubiquitination of FANCD2 and FANCI. In contrast, monoubiquitination requires the entire helicase domain of FANCM, which has both ATP dependent and independent activities. These data are consistent with participation of FANCM and its associated FA core complex in the FA pathway at both signaling through monoubiquitination and the ensuing DNA repair.
Xue
Yutong
Y
Laboratory of Genetics, National Institute on Aging, National Institutes of Health, 333 Cassell Drive, TRIAD Center Room 3000, Baltimore, MD 21224, USA.
Li
Yongjiang
Y
Guo
Rong
R
Ling
Chen
C
Wang
Weidong
W
D000255:Adenosine Triphosphate / Q000378:metabolism; D002460:Cell Line; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism; D019281:Dimerization; D004351:Drug Resistance; D052236:Fanconi Anemia Complementation Group D2 Protein / Q000378:metabolism; D051856:Fanconi Anemia Complementation Group Proteins / Q000378:metabolism; D006801:Humans; D016685:Mitomycin / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000235:genetics; D011995:Recombination, Genetic; D054875:Ubiquitination
D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; C518296:FAAP24 protein, human; C519921:FANCI protein, human; D052236:Fanconi Anemia Complementation Group D2 Protein; D051856:Fanconi Anemia Complementation Group Proteins; D034741:RNA, Small Interfering; D016685:Mitomycin; D000255:Adenosine Triphosphate; D004247:DNA; C518295:FANCM protein, human; D004265:DNA Helicases