Chapter 10 Homologous Recombination 27 and 29 September, 2004
Overview • Homologous recombination relies on regions of nearly identical sequence. • The Holliday model of the mechanism of recombination involves recognition, strand invasion, branch migration, and resolution. • The Double-strand Break Repair model is similar, but involves two Holliday junctions. • Homologous recombination is mediated by protein enzymes. • RecA (Rad51p) pairs homologous regions and promotes strand exchange. • RecBCD (Rad 50/58/60p; MRXp) generates single strand for invasion. • RuvAB and RuvC (?) promote branch migration and resolution. • Homologous recombination is required for successful meiosis. • In meiosis, Spo11 generates DSB, MRXp extends the break, and Rad51 promotes strand invasion. • Some events, including mating-type switching in yeast and VDJ recombination involve regulated, specific recombination.
The mechanism of mating-type conversion involves replication to bring about gene conversion.