Sos repair mechanism

SOS repair
a system that repairs severely damaged bases in DNA by base excision and replacement, even if there is no template to guide base selection. This process is a last resort for repair and is often the cause of mutations.

1. SOS REPAIR MECHANISM Submitted by : Varnit C hauhan Integrated B.Tech+M.tech 5 th sem .

2. Sos repair Stand for ‘Save Our Ship’. Occurs when cells are overwhelmed by UV damage. Triggered when other repair systems are overwhelmed by amount of damage. The error-prone(SOS) repair mechanism involves DNA pol. III and 2 other gene products encoded by umuCD .

3. The sos response In response to extensive genetic damage there is a regulatory system that co-ordinates the bacterial cell response. This results in the increased expression of >30 genes, involved in DNA repair, these include: recA - activator of SOS response, recombination sfiA ( sulA ) - a cell division inhibitor (repair before replication) umuC , D - an error prone bypass of thymine dimers (loss of fidelity in DNA replication) uvrA,B,C,D - excision repair The SOS response is regulated by two key genes: recA & lexA

4. SOS response is controlled by LexA and RecA