FANCJ (BACH1) helicase forms DNA damage inducible foci with replication protein A and interacts physically and functionally with the single-stranded DNA-binding protein
Department of Cancer Biology
Basic-Leucine Zipper Transcription Factors; Cell Line; DNA Damage; DNA Helicases; DNA-Binding Proteins; Fanconi Anemia; Fanconi Anemia Complementation Group Proteins; Humans; Kinetics; Mutation; Protein Binding; RNA, Small Interfering; Replication Protein A
The BRCA1 associated C-terminal helicase (BACH1, designated FANCJ) is implicated in the chromosomal instability genetic disorder Fanconi anemia (FA) and hereditary breast cancer. A critical role of FANCJ helicase may be to restart replication as a component of downstream events that occur during the repair of DNA cross-links or double-strand breaks. We investigated the potential interaction of FANCJ with replication protein A (RPA), a single-stranded DNA-binding protein implicated in both DNA replication and repair. FANCJ and RPA were shown to coimmunoprecipitate most likely through a direct interaction of FANCJ and the RPA70 subunit. Moreover, dependent on the presence of BRCA1, FANCJ colocalizes with RPA in nuclear foci after DNA damage. Our data are consistent with a model in which FANCJ associates with RPA in a DNA damage-inducible manner and through the protein interaction RPA stimulates FANCJ helicase to better unwind duplex DNA substrates. These findings identify RPA as the first regulatory partner of FANCJ. The FANCJ-RPA interaction is likely to be important for the role of the helicase to more efficiently unwind DNA repair intermediates to maintain genomic stability.
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Citation: Blood. 2007 Oct 1;110(7):2390-8. Epub 2007 Jun 27. Link to article on publisher's site