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A novel mutator of Escherichia coli carrying a defect in the dgt gene, encoding a dGTP triphosphohydrolase
- Source :
- Journal of Bacteriology. Nov, 2008, Vol. 190 Issue 21-22, p6931, 9 p.
- Publication Year :
- 2008
-
Abstract
- A novel mutator locus in Escherichia coli was identified from a collection of random transposon insertion mutants. Several mutators in this collection were found to have an insertion in the dgt gene, encoding a previously characterized dGTP triphosphohydrolase. The mutator activity of the dgt mutants displays an unusual specificity. Among the six possible base pair substitutions in a lacZ reversion system, the G * C[right arrow]C * G transversion and A * T [right arrow] G * C transition are strongly enhanced (10- to 50-fold), while a modest effect (two- to threefold) is also observed for the G * C [right arrow] A * T transition. Interestingly, a two- to threefold reduction in mutant frequency (antimutator effect) is observed for the G * C [right arrow] T * A transversion. In the absence of DNA mismatch repair (mutL) some of these effects are reduced or abolished, while other effects remain unchanged. Analysis of these effects, combined with the DNA sequence contexts in which the reversions take place, suggests that alterations of the dGTP pools as well as alterations in the level of some modified dNTP derivatives could affect the fidelity of in vivo DNA replication and, hence, account for the overall mutator effects.
- Subjects :
- DNA replication
Escherichia coli
Genetic research
Water quality
Biological sciences
Subjects
Details
- Language :
- English
- ISSN :
- 00219193
- Volume :
- 190
- Issue :
- 21-22
- Database :
- Gale General OneFile
- Journal :
- Journal of Bacteriology
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.189160366