Counteraction by MutT Protein of Transcriptional Errors Caused by Oxidative Damage

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Science  03 Oct 1997:
Vol. 278, Issue 5335, pp. 128-130
DOI: 10.1126/science.278.5335.128

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Oxidized guanine (8-oxo-7,8-dihydroguanine; 8-oxo-G) is a potent mutagen because of its ambiguous pairing with cytosine and adenine. TheEscherichia coli MutT protein specifically hydrolyzes both 8-oxo-deoxyguanosine triphosphate (8-oxo-dGTP) and 8-oxo-guanosine triphosphate (8-oxo-rGTP), which are otherwise incorporated in DNA and RNA opposite template A. In vivo, this cleaning of the nucleotide pools decreases both DNA replication and transcription errors. The effect ofmutT mutation on transcription fidelity was shown to depend on oxidative metabolism. Such control of transcriptional fidelity by the ubiquitous MutT function has implications for evolution of RNA-based life, phenotypic expression, adaptive mutagenesis, and functional maintenance of nondividing cells.

  • * Present address: Institut National de la Santé et de la Recherche Médicale.

  • To whom correspondence should be addressed. E-mail: taddei{at}

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