Analysis of the nag regulon from Escherichia coli K12 and Klebsiella pneumoniae and of its regulation.
Four genes, nagR, A, B and E, clustered in the nag locus of Escherichia coli K12 and Klebsiella pneumoniae, were cloned and physically mapped, and the corresponding gene products involved in amino sugar metabolism identified. Expression of the nag genes was also analysed using a series of lacZ fusions. In both bacteria, the genes are arranged in two divergent operons and controlled by a common NagR repressor. The corresponding gene nagR was found to map in the first operon together with the promoter proximal gene nagB, encoding the enzyme D-glucosamine isomerase (deaminase) (NagB) and the middle gene nagA, coding for N-acetyl-glucosamine deacetylase (NagA). Polar mutations in nagB and nagA prevent the efficient expression of nagR and cause constitutive expression of all nag genes. This includes the gene nagE encoding Enzyme IINag of the phosphoenolpyruvate-dependent carbohydrate phosphotransferase system (PTS), encoded in the second divergently transcribed operon. No further gene is found in this operon which in both organisms is directly adjacent to the gene glnS. It is interesting that the NagR repressor also affects the mannose PTS (genes manX, Y, Z), the second transport system involved in amino sugar uptake and phosphorylation.
Vogler
A P
AP
Universität Osnabrück, Fachbereich Biologie/Chemie, Federal Republic of Germany.
Lengeler
J W
JW
D000117:Acetylglucosamine / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D004303:Dosage Compensation, Genetic; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator; D005838:Genotype; D005944:Glucosamine / Q000031:analogs & derivatives*; D007711:Klebsiella pneumoniae / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D009876:Operon; D010641:Phenotype; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics; D010957:Plasmids; D012097:Repressor Proteins / Q000235:genetics*; D015183:Restriction Mapping; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C067862:nagC protein, E coli; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D005944:Glucosamine; D000117:Acetylglucosamine