Molecular characterization of a human BRCA2 homolog in Leishmania donovani.

The breast cancer susceptibility protein BRCA2 is implicated in the DNA double-strand break (DSB) repair pathway through its association with Rad51. It is almost a ubiquitous eukaryotic protein; homologs of the BRCA2 gene (BRH2) have been identified in many mammals, as well as nonmammals. As a part of our quest to understand the DNA damage, repair, and recombination process in the parasitic protozoan, Leishmania sp., we have cloned and characterized a BRCA2 homolog from Leishmania sp. (LBRH2). LBRH2 is coded by a single-copy gene (ORF = 3,498 bp) located at the 700-kb chromosome 16. The transcripts in both the promastigotes and the amastigotes are approximately 3.9 kilonucleotides (knt) in size, corresponding to a protein with a calculated molecular mass of 128 kDa. The primary transcript of the gene is alternatively trans-spliced to produce 3 distinct mRNAs with altered folded structures at their 5' ends. This study will contribute toward the understanding of a potential RAD51-mediated DNA recombination/repair pathway in Leishmania sp.