title: A simple and rapid method to obtain substitution mutations in Escherichia coli: isolation of a dam deletion/insertion mutation.
abstract: We describe the isolation of a strain of Escherichia coli bearing a deletion/insertion (i.e., a substitution mutation) in the dam gene (dam-16). The mutagenesis protocol used should be applicable to any cloned non-essential gene of E. coli. The substitution mutation confers resistance to kanamycin and can easily be transferred to other strains by standard genetic techniques. The amount of Dam methyltransferase (MTase) in dam-16 strains as determined either in vitro or in vivo is below the level of detection. We conclude that the Dam MTase is not required for viability of E. coli.
authors.affiliation: Department of Pharmacology, University of Massachusetts Medical School, Worcester 01655.
authors.forename: B
authors.initials: B
authors.lastname: Parker
authors.forename: M G
authors.initials: MG
authors.lastname: Marinus
mesh_terms: D002872:Chromosome Deletion; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D003433:Crosses, Genetic; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005796:Genes; D005798:Genes, Bacterial; D005838:Genotype; D009154:Mutation; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000235:genetics*; D014161:Transduction, Genetic
chemical_list: D004251:DNA Transposable Elements; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)