RAD-51-Dependent and -Independent Roles of a Caenorhabditis elegans BRCA2-Related Protein during DNA Double-Strand Break Repair

JS Martin, N Winkelmann, MIR Petalcorin… - … and cellular biology, 2005 - Taylor & Francis
JS Martin, N Winkelmann, MIR Petalcorin, MJ McIlwraith, SJ Boulton
Molecular and cellular biology, 2005Taylor & Francis
The BRCA2 tumor suppressor is implicated in DNA double-strand break (DSB) repair by
homologous recombination (HR), where it regulates the RAD51 recombinase. We describe
a BRCA2-related protein of Caenorhabditis elegans (CeBRC-2) that interacts directly with
RAD-51 via a single BRC motif and that binds preferentially to single-stranded DNA through
an oligonucleotide-oligosaccharide binding fold. Cebrc-2 mutants fail to repair meiotic or
radiation-induced DSBs by HR due to inefficient RAD-51 nuclear localization and a failure to …
The BRCA2 tumor suppressor is implicated in DNA double-strand break (DSB) repair by homologous recombination (HR), where it regulates the RAD51 recombinase. We describe a BRCA2-related protein of Caenorhabditis elegans (CeBRC-2) that interacts directly with RAD-51 via a single BRC motif and that binds preferentially to single-stranded DNA through an oligonucleotide-oligosaccharide binding fold. Cebrc-2 mutants fail to repair meiotic or radiation-induced DSBs by HR due to inefficient RAD-51 nuclear localization and a failure to target RAD-51 to sites of DSBs. Genetic and cytological comparisons of Cebrc-2 and rad-51 mutants revealed fundamental phenotypic differences that suggest a role for Cebrc-2 in promoting the use of an alternative repair pathway in the absence of rad-51 and independent of nonhomologous end joining (NHEJ). Unlike rad-51 mutants, Cebrc-2 mutants also accumulate RPA-1 at DSBs, and abnormal chromosome aggregates that arise during the meiotic prophase can be rescued by blocking the NHEJ pathway. CeBRC-2 also forms foci in response to DNA damage and can do so independently of rad-51. Thus, CeBRC-2 not only regulates RAD-51 during HR but can also function independently of rad-51 in DSB repair processes.
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