HR is initiated by the recognition of a DSB, which is then processed to produce single-stranded DNA (ssDNA) tails. Proteins such as Rad51 bind to these ssDNA tails to form nucleoprotein filaments, which search for a homologous sequence on a sister chromatid. Once a homologous sequence is found, strand invasion occurs, forming a Holliday junction. The process is completed by DNA synthesis, branch migration, and resolution of the Holliday junction, resulting in the accurate repair of the DSB.
