title: Comparison of transcription of beta-lactamase genes specified by various ampicillin transposons.
abstract: The beta-lactamase gene from four kinds of ampicillin transposons, Tn2601, Tn3, Tn2602 and Tn1, specifying the type I (or TEM type, alternatively) beta-lactamase was cloned onto plasmid pACYC184, and the level of in vivo transcription from each beta-lactamase gene was determined by DNA-RNA hybridization. Type I beta-lactamase is very uniform enzymologically, but heterogeneous in absolute levels of enzyme activity. The results demonstrated that the heterogeneity can be explained by the efficiency of transcription of each beta-lactamase gene, suggesting a difference in its promoter efficiency. A comparison of the levels of transcription of the beta-lactamase gene and the whole ampicillin transposon suggested that the beta-lactamase gene has the strongest promoter all of the genes in the ampicillin transposon.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology*; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000235:genetics; D005796:Genes; D005798:Genes, Bacterial; D009876:Operon; D014158:Transcription, Genetic; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D004251:DNA Transposable Elements; D000667:Ampicillin; D001618:beta-Lactamases