Biomaterial Database

Multiple regulatory signals in the control region of the Escherichia coli carAB operon. 1984

J Bouvier, and J C Patte, and P Stragier

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 can be initiated in vivo without an AUG codon but very likely with an UUG or an AUU codon; (ii) the carAB downstream promoter is repressed by arginine; and (iii) the carAB upstream promoter is repressed by pyrimidines and subject to stringent control. When carried by a multicopy plasmid the carAB control region escapes repression by arginine and pyrimidines. The existence of a pyrimidine repressor, present in limiting amounts in the cell, is therefore postulated.

UI	MeSH Term	Description	Entries
D008025	Ligases	A class of enzymes that catalyze the formation of a bond between two substrate molecules, coupled with the hydrolysis of a pyrophosphate bond in ATP or a similar energy donor. (Dorland, 28th ed) EC 6.	Ligase,Synthetases,Synthetase
D009876	Operon	In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.	Operons
D002223	Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing)	An enzyme that catalyzes the formation of carbamoyl phosphate from ATP, carbon dioxide, and glutamine. This enzyme is important in the de novo biosynthesis of pyrimidines. EC 6.3.5.5.	Carbamyl Phosphate Synthase (Glutamine),Carbamoyl-Phosphate Synthase (Glutamine),Carbamoylphosphate Synthetase II,Carbamyl Phosphate Synthase II,Carbamyl-Phosphate Synthase (Glutamine),Synthetase II, Carbamoylphosphate
D003562	Cytidine	A pyrimidine nucleoside that is composed of the base CYTOSINE linked to the five-carbon sugar D-RIBOSE.	Cytosine Ribonucleoside,Cytosine Riboside,Ribonucleoside, Cytosine,Riboside, Cytosine
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005796	Genes	A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.	Cistron,Gene,Genetic Materials,Cistrons,Genetic Material,Material, Genetic,Materials, Genetic
D005798	Genes, Bacterial	The functional hereditary units of BACTERIA.	Bacterial Gene,Bacterial Genes,Gene, Bacterial
D005809	Genes, Regulator	Genes which regulate or circumscribe the activity of other genes; specifically, genes which code for PROTEINS or RNAs which have GENE EXPRESSION REGULATION functions.	Gene, Regulator,Regulator Gene,Regulator Genes,Regulatory Genes,Gene, Regulatory,Genes, Regulatory,Regulatory Gene
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D001120	Arginine	An essential amino acid that is physiologically active in the L-form.	Arginine Hydrochloride,Arginine, L-Isomer,DL-Arginine Acetate, Monohydrate,L-Arginine,Arginine, L Isomer,DL Arginine Acetate, Monohydrate,Hydrochloride, Arginine,L Arginine,L-Isomer Arginine,Monohydrate DL-Arginine Acetate