Introduction to Genetic Analysis 461

Introduction to Genetic Analysis 461 - 44200_14_p451-480...

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

View Full Document Right Arrow Icon
460 Chapter 14 Mutation, Repair, and Recombination polymerase (DNA polymerase III) stalls at a site of DNA damage, the DNA ahead of the polymerase continues to be unwound, exposing regions of single-stranded DNA that become bound by single-strand-binding protein (SSB). Next, RecA proteins join the SSB and form a protein– DNA Flament. The RecA Flament is the biologically active form of this protein. In this situation, RecA acts as a signal that leads to the induction of the error-prone polymerase and attracts it to the stalled fork. Mutagens that create bases unable to form stable base pairs are thus dependent on SOS and similar sys- tems for their mutagenic action, because the incorpora- tion of incorrect nucleotides requires the activation of the SOS system. The category of SOS-dependent mu- tagens is important because it includes most cancer- causing agents (carcinogens), such as ultraviolet (UV) light and a±atoxin B 1 . Indeed, a great deal of work has been done on the relationship of mutagens to carcino- gens. The connections between mutation and cancer will
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 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.

Ask a homework question - tutors are online