A specific inhibition of induction of adaptive response by [formula omitted]-vanillin, a potent comutagen

Abstract

The present study revealed that potent comutagenic activity of o -vanillin in mutagenesis by N -methyl- N -nitrosourea (MNU) is a consequence of inhibition of the transcriptional promoting capacity of methylated O 6-methylguanine-DNA methyltransferase (MGTase). As evidence of this, in the presence of o -vanillin, there were (i) dose-dependent decreases in MGTase induced in E. coli exposed to MNU, (ii) inhibition of ada gene promotion determined in the ada′ - lacZ′ assay system, and (iii) minimal inhibition of the methyl transfer capacity of MGTase in a subcellular system.