The BRCA2 is located in region 12 of the long arm of chromosome 13 and consists of 27 coding exons, the largest being exon 11 (4.9 kb). BRCA2 encodes a protein of 3418 amino acids (10.2 kb). The N-terminus of BRCA2 binds to PALB2. In addition, BRCA2 contains 8 BRC repeats located between amino acid residues 1009 to 2083 and binds to RAD51. The BRCA2 gene DNA binding domain contains 5 components: a 190 amino acid alpha helix domain (H), 3 oligonucleotide binding folds (single-stranded DNA binding module), and a tower-like domain (T) that extends from 3 oligonucleotide binding 2 and binds to dsDNA to bind single-stranded DNA. The C-terminus of BRCA2 contains an NLS and a phosphorylation site S3291 for cyclin-dependent kinase, which also binds to RAD51.
The BRCA2 gene mediates the recruitment of RAD51 filaments to the DNA double-strand break site and interacts in the repair process to form the RAD51-BRCA2-DSS1 complex, which uses sister chromatids as a template to repair damage through “error-free” homologous recombination. The BRCA2 gene also appears to participate in cytoplasmic division; when its function is disrupted, cytoplasmic division is impaired, and the incidence of binucleated cells is increased. Studies have also shown that BRCA2 gene-deficient cells exhibit alterations in chromosome number (aneuploidy) as well as structurally abnormal chromosomes, resulting in BRCA2 gene-deficient tumors that are frequently aneuploid. In addition to its DNA repair function, BRCA2 inhibits tumor development by suppressing cancer cell growth.