Transcriptional induction of Streptomyces cacaoi beta-lactamase by a beta-lactam compound.
The soil bacterium Streptomyces cacaoi produces an extracellular beta-lactamase. The beta-lactamase expression could be induced by the beta-lactam compound 6-amino penicillinoic acid (6-APA). In liquid cultures, a 50-fold increase in beta-lactamase expression was observed within the first three hours after addition of 6-APA. Using the cloned beta-lactamase gene as a probe, it was shown that this increase was mediated at the level of transcriptional initiation. The start point of the induced beta-lactamase transcript was determined, and the nucleotide sequence of the promoter region was analysed. No noticeable homology was found to control regions of inducible beta-lactamase genes of other bacteria. A striking feature was the presence of six direct repeats (ten base pairs each) upstream of the promoter region. Thus, an example of an inducible regulatory gene system in this Gram-positive microorganism is presented. Also, the primary structure of the beta-lactamase was deduced, showing a high degree of homology with class A beta-lactamases.
Forsman
M
M
Department of Cell- and Microbiology, National Defence Research Establishment, Umeå, Sweden.
Lindgren
L
L
Häggström
B
B
Jaurin
B
B
D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D010397:Penicillanic Acid / Q000494:pharmacology* / Q000031:analogs & derivatives; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics; D014158:Transcription, Genetic / Q000502:physiology; D001618:beta-Lactamases / Q000235:genetics*
D010397:Penicillanic Acid; D001618:beta-Lactamases; C004408:aminopenicillanic acid