Murine Brca2: sequence, map position, and expression pattern.

Mutations in the human BRCA2 gene are responsible for about 45% of hereditary early onset breast cancer. Recently, the human BRCA2 gene was cloned, and several germline mutations were identified. Here we describe the cloning of the mouse homologue of BRCA2. The mouse cDNA sequence predicts a 3328-amino-acid Brca2 protein, 90 amino acids shorter than the human protein. The overall identity between the mouse and the human proteins is 59%, while the similarity is 72%. At the nucleotide level the homology is 74%. By comparing the amino acid sequences of the two homologues we have identified five highly conserved novel domains that may be functionally significant. Brca2 has been mapped to the distal end of mouse chromosome 5, a region of the mouse genome that contains other genes that also map to human chromosome 13q12-q13, confirming the conservation of this linkage group between the two species. Expression of Brca2 was detected in midgestation embryos and adult testis, thymus, and ovary.