Chapter category: DNA Surveillance and Repair
Mammalian Base Excision Repair
Eukaryotic DNA Damage Surveillance and Repair
Edited by: Keith W. CaldecottISBN: 0-306-47987-7
» Get more information about this book at landesbioscience.com «
Chapter authors:
Grigory L. Dianov, Sarah L. Allinson, Helen Budworth and Kate Sleeth
In living cells DNA base lesions are formed continuously as a consequence of normal me tabolism and are also generated by a number of external factors. Simple base damages are repaired by base excision repair that includes two major pathways. These two pathways involve different subsets of enzymes and result in replacement of one (short-patch pathway) or more (long-patch pathway) nucleotides. Both pathways are initiated by a damage specific DNA glycosylase, which removes the damaged base creating an abasic site (apurinic/apyrimidinic, AP site). AP endonuclease then cleaves the phosphodiester bond 5' to the AP site and then DNA polymerase b adds the first nucleotide to the 3'-end of the incised AP site. Normally, the reaction continues through the short-patch repair pathway where Pol b removes the 5'-sugar phosphate residue and DNA ligase complete the repair. However, if the 5'-sugar phosphate is resistant to b-elimination, catalyzed by DNA polymerase b, then additional DNA synthesis is required to displace the 5'-sugar phosphate as part of a flap. This flap is then removed by flap endonuclease, and DNA ligase completes long-patch repair by ligating the DNA ends. These processes are directed and coordinated by multiple protein-protein interactions.
Additional chapters from this book:
Mammalian Base Excision Repair
Grigory L. Dianov, Sarah L. Allinson, Helen Budworth and Kate Sleeth
In living cells DNA base lesions are formed continuously as a consequence of normal me tabolism and are also generated by a number of external factors. Simple base damages are repaired by base ex...
Origin, Recognition, Signaling and Repair of DNA Double-Strand Breaks in Mammalian Cells
Larry H. Thompson and Charles L. Limoli
Achromosomal double-strand break (DSB) can arise from multiple sources including ionizing radiation and DNA replication itself. An understanding of the intricate pro tein pathways that recognize ...
The Detection and Repair of Nucleotide Damage and Coupling to Major Cellular Regulatory Processes in Mammalian Cells
James E. Cleaver
DNA repair serves to restore two of the main macromolecular functions in the cell: DNA replication and transcription. If either are irrevocably blocked cell death in the form of apoptosis or per...
Mammalian DNA Mismatch Repair
Helen M.R. Robinson and Robert Brown
Some DNA replication errors escape the proof reading activity of DNA polymerases and if allowed to persist will lead to mutations and potential creation of an abnormal mutant cell. Therefore suc...
