An in Vivo approach to identifying sequence context of 8-oxoguanine mutagenesis

Takashi Watanabe, Tatsuo Nunoshiba, Masakado Kawata, Kazuo Yamamoto

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Base substitution mutations are not distributed randomly in that most are located at a few specific hotspots sites. We have been studying 7,8-dihydro-8-oxoguanine mutagenesis in Escherichia coli in the supF gene carried in a plasmid. Among hotspots, guanine within the 5′-AGA-3′ located in the anticodon site was susceptible to the induction of G:CT→:A transversion. In this study, we constructed variants of the supF gene in which the hotspot 5′-AGA-3′ was modified to 5′-AGT-3′, 5′-AGG-3′ and 5′-AGC-3′ to determine the influence of 3′ neighboring base on G:C→T:A mutational activity. Using these variant supF genes propagated in a 7,8-dihydro-8-oxoguanine repair-deficient host, we found that guanine within 5′-AGA-3′ and 5′-AGG-3′ produce G:C→T:A, but guanine within 5′-AGT-3′ and 5′-AGC-3′ reduce the formation of G:C→T:A. These changes were thus due to the effect of sequence context on the efficiency of mutation formation at the sites of 7,8-dihydro-8-oxoguanine. We also observed a longer range base-pair effect on hotspot formation.

Original languageEnglish
Pages (from-to)179-184
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - 2001


  • 7,8-dihydro-8-oxoguanine
  • Mutation hotspot
  • MutM
  • MutY
  • supF gene


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