RAD51

Rad51 is the eukaryotic homolog of the prokaryotic RecA protein. It is well conserved from yeast to humans.

Function
In humans, Rad51 is a 339-amino acid protein that plays a major role in homologous recombination of DNA during double strand break repair. In this process, an ATP dependent DNA strand exchange takes place in which a template strand invades base-paired strands of homologous DNA molecules. Rad51 is involved in the search for homology and strand pairing stages of the process.

Unlike other proteins involved in DNA metabolism, the RecA/Rad51 family forms a helical nucleoprotein filament on DNA.

The structural basis for Rad51 filament formation and its functional mechanism still remain poorly understood.

Pathology
The Rad51 gene is located on chromosome 15 and several alterations of the gene have been associated with an increased risk of developing breast cancer. The breast cancer susceptibility protein BRCA2 controls the function of Rad51 in the pathway for DNA repair by homologous recombination.

Family
In mammals, seven recA-like genes have been identified: Rad51, Rad51L1/B, Rad51L2/C, Rad51L3/D, XRCC2, XRCC3 and DMC1. Of these, with the exception of meiosis-specific DMC1, are essential for development in mammals.