MBIO 4600 Lecture Notes - Lecture 18: Damage Tolerance, Homologous Recombination, Dna Replication
25 Dec 2015
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Pria system: pria, prib, pric, dnat, helicase activity, restart of replication forks, if mutated, reduced recombination (cid:1) Entails use of recombination functions to allow fork to bypass dna damage. Leading and lagging strands exchange information allowing reassembly of replication apparatus to reassemble on other side of damage. Oh: helicase drives holliday junction past damage (cid:1) (cid:1, pria system loads dnab; replication resumes. Two bases in the opposite strands of the dna are covalently joined to each other. Often caused by exposure to chemicals (e. g. ems) Problematic damage for repair systems: excision repair double-strand breakage cell death, cross linkage prevents strand separation, so no recombination function repair. Observed that irradiated survived better in pre-irradiated e. coli cells than in non-irradiated cells. Induced repair system could repair e. coli dna and dna: class of genes that comprise induced repair system din (damage inducible) genes, include products of uvr and recombination repair pathways.
