DNA - Repair Mechanism Lesion Bypass When does it happen?...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Repair Mechanism When does it happen? How does it work? What is the outcome? Lesion Bypass During replication- have to keep going! WIll replicate through Thymine dimer Switches normal Pol for special Pols that can blow through the damage. Are good at recognizing Tdimer Often causes mutation-- but lets cell live (replication doesn t stall) Direct Reversal When bases are chemically damaged (thymine dimer, methylation damage) Photoreactivation: reverses Tdimer with visible light. Methyltransferase: reverse met damage No mutations-- just reverses base damage Damage Removal: When you need to correct mistakes the Pol made or DNA damage Excise damaged area and repolymerize fresh DNA Generally corrects damage, no mutations (excepting ds Break repair non-homologous) 1. Base excision repair Single base is damaged or converted to U 1-2 base removed then residue removed, polymerase adds new NTP Corrects damage, no mutation-- uses other un-damaged strand as template 2. Mismatch excision repair Proofreading after
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 07/08/2009 for the course LIFESCI LS 3 taught by Professor Paulolague during the Fall '09 term at UCLA.

Ask a homework question - tutors are online