Approaches to the Analysis of Fidelity of DNA Repair in Mammalian Cells

This chapter discusses approaches to the analysis of fidelity of DNA repair in mammalian cells. The different types of DNA repair includes: (1) photoreactivation, (2) excision and DNA repair synthesis, (3) repair of single-strand breaks, depurinated Sites, and small base adducts, (4) post replication repair and recombination, and (5) host cell reactivation. There are two major approaches to the analysis of fidelity in mammalian cells. The first involves structural (chemical) analysis of restored areas, while the other involves biological evaluation (survival, host cell reactivation, genetic analysis) of cells damaged with various agents. Physical and chemical studies of repair synthesis following excision of damage indicate that in mammalian cells restoration of the damaged region is an orderly accurate process which appears to use the undamaged, complementary strand as a template for nucleotide insertion. An important aspect of repair processes in relation to carcinogenesis is the degree to which these processes themselves may introduce errors that may be carcinogenic. Several studies in bacteria emphasized error-prone and error-free repair processes.