Practice question

Rad51 is eukaryotic ortholog of bacterial RecA and central recombinase for homologous recombination. Expression is not restricted to meiotic tissue; it operates in mitotic somatic cells repairing collapsed forks and double-strand breaks using sister chromatid template, and in meiotic cells alongside Dmc1. Rad51 forms presynaptic filament that executes homology search, invasion, and D-loop formation. Its activity regulated by mediators BRCA2, Rad52, and Rad51 paralogs that facilitate RPA displacement. Loss causes hypersensitivity to ionizing radiation, embryonic lethality, and cancer predisposition in both mitotic and meiotic contexts.