Abstract
Nudix hydrolases are a family of proteins that hydrolyze a variety of nucleoside diphosphate derivatives. E.coli MutT hydrolyzes 8-oxo-dGTP and 8-oxo-GTP, the oxidized form of free guanine nucleotide, to prevent the mutation induced by such nucleotides. We found that Arabidopsis thaliana contains a number of cytosolic MutT/Nudix hydrolases (AtNUDX1-11). In this study, we characterized AtNUDX1, a MutT homolog, in Arabidopsis thaliana. The recombinant AtNUDX1 protein had the ability to hydrolyze not only 8-oxo-dGTP but also 8-oxo-GTP. In addition, AtNUDX1 completely suppressed increased frequency of spontaneous mutations in the E.coli mutT strain. These results indicate that AtNUDX1 functions to prevent the mutation of both DNA and RNA in A. thaliana. No phenotypic difference was observed between the wild-type plants and AtNUDX1-KO mutant under the oxidative stress caused by the treatment with 2μM paraquat. We are progressing toward to examine the 8-oxo-dG content in their plants.
