MBB 222 Lecture Notes - Lecture 19: Robin Holliday, Holliday Junction, Homologous Recombination

• School: Simon Fraser University
• Department: Molec Biol & Biochem
• Course: MBB 222
• Professor: dr.chu

Document Summary

Dna recombinaion: rearrangement of geneic informaion within and among dna molecules. Some examples: crossing over between non-sister chromaids in meiosis, integraion of viral genomes into host cell chromosomes, generaing molecular diversity in anibodies, repair of the replicaion forks stalled at the site of dna damage. Strand invasion : nicks are sealed - the crossover point is a four-stranded structure called a holliday juncion, the holliday juncion can move in either direcion of the duplex by unwinding and rewinding - branch migraion. Non-recombinant duplexes: each also contains a segment of one strand that is diferent from the original strand, called a heteroduplex region. Recombinant duplexes: the strands will have swapped alleles, both having a heteroduplex region. Isomerizaion and resoluion (cleavage), non-recombinant and recombinant duplexes will be generated, as seen for the holliday model. Reca protein polymerizes on single stranded dna to form a nucleoprotein ilament.