Characterization of mutations induced by N-methyl-N'-nitro-N-nitrosoguanidine in an industrial Corynebacterium glutamicum strain

Mutat Res. 2008 Jan 8;649(1-2):239-44. doi: 10.1016/j.mrgentox.2007.10.003. Epub 2007 Oct 18.

Abstract

Mutations induced by classical whole-cell mutagenesis using N-methyl-N'-nitro-N-nitrosoguanidine (NTG) were determined for all genes of pathways from glucose to L-lysine in an industrial L-lysine producer of Corynebacterium glutamicum. A total of 50 mutations with a genome-wide distribution were identified and characterized for mutational types and mutagenic specificities. Those mutations were all point mutations with single-base substitutions and no deletions, frame shifts, and insertions were found. Among six possible types of base substitutions, the mutations consisted of only two types: 47 G.C-->A.T transitions and three A.T-->G.C transitions with no transversion. The findings indicate a limited repertoire of amino acid substitutions by classical NTG mutagenesis and thus raise a new possibility of further improving industrial strains by optimizing key mutations through PCR-mediated site-directed mutagenesis.

MeSH terms

  • Corynebacterium glutamicum / drug effects*
  • Corynebacterium glutamicum / genetics*
  • DNA Mutational Analysis
  • Genome, Bacterial
  • Methylnitronitrosoguanidine / toxicity*
  • Mutagenicity Tests
  • Point Mutation / drug effects*

Substances

  • Methylnitronitrosoguanidine