title: Molecular basis of base substitution hotspots in Escherichia coli.
abstract: In the lacI gene of Escherichia coli spontaneous base substituion hotspots occur at 5-methylcytosine residues. The hotspots disappear when the respective cytosines are not methylated. We suggest that the hotspots may result from the spontaneous deamination of 5-methylcytosine to thymine, which is not excised by the enzyme DNA-uracil glycosidase.
mesh_terms: D015075:2-Aminopurine / Q000494:pharmacology; D001483:Base Sequence; D003062:Codon; D003596:Cytosine / Q000031:analogs & derivatives; D004926:Escherichia coli / Q000235:genetics*; D005796:Genes; D007785:Lactose / Q000235:genetics*; D009153:Mutagens; D009154:Mutation / Q000187:drug effects / Q000528:radiation effects; D010443:Peptide Chain Termination, Translational; D014466:Ultraviolet Rays
chemical_list: D003062:Codon; D009153:Mutagens; D015075:2-Aminopurine; D003596:Cytosine; D007785:Lactose