Multiple regulatory signals in the control region of the Escherichia coli carAB operon.

ABSTRACT: The first reaction in pyrimidine and arginine biosynthesis in Escherichia coli is catalyzed by a single enzyme, carbamoyl-phosphate synthetase (EC 6.3.5.5), the product of the carAB operon. Expression of this operon is cumulatively repressed by arginine and pyrimidines. The nucleotide sequence of the carAB control region was determined and transcriptional starts were localized. Two adjacent promoters, 70 base pairs apart, appear to be used in vivo, the downstream one overlapping a typical arginine operator. The absence of any attenuation-like sequence excludes such a mechanism for pyrimidine-mediated repression. Various fragments of the carA promoter-proximal region were fused in vitro with the lacZ gene. Results obtained with these fusions indicate that (i) translation of the carA gene ca

SUBMITTER: Bouvier J 

PROVIDER: S-EPMC345384 | biostudies-literature | 1984 Jul

REPOSITORIES: biostudies-literature