Tóm tắt
Mutator mutants that show an increased frequency of spontaneous mutation have led to the elucidation of the multiple pathways of spontaneous mutagenesis. 8‐Oxo‐dGTP (8‐oxo‐7,8‐dihydrodeoxyguanosine triphosphate) is formed in the nucleotide pool of a cell during normal cellular metabolism, and when it is incorporated into DNA causes mutation. MutT protein of Escherichia coli and related mammalian enzymes specifically degrade 8‐oxo‐dGTP to 8‐oxo‐dGMP, thereby preventing occurrence of transversion mutation. The gene encoding the human enzyme, designated MTH1 (for mutT homologue 1), maps to chromosome 7p22. These proteins may be responsible for genomic stability.
