Role of the catabolite activator protein in the expression of the maltose regulon of Escherichia coli.
Using malT-lacZ strains deleted for gene crp, we have shown that the expression of malT is controlled by the catabolite activator protein (CAP), the product of gene crp. malT X mutations were obtained which allowed a malT-lacZ hybrid gene to be expressed at a high level even in the absence of CAP. These mutations were shown to be located in or close to the promoter of the malT gene. We transferred the malT X mutation cis to a wild type malT gene. In the resulting strains, the study of the expression of the three operons in absence or presence of CAP led us to the following conclusion. CAP appears to control malPQ expression mainly if not only by regulating the concentration of MalT protein in the cell. On the other hand it controls the two other operons more stringently both by regulating malT expression and by a more direct action probably exerted on the promoters of these operons.
D001425:Bacterial Outer Membrane Proteins; D010582:Bacteriophage lambda; D000242:Cyclic AMP / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D008320:Maltose / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D018272:Porins; D011953:Receptors, Cyclic AMP / Q000378:metabolism*; D011991:Receptors, Virus / Q000235:genetics
D001425:Bacterial Outer Membrane Proteins; D018272:Porins; D011953:Receptors, Cyclic AMP; D011991:Receptors, Virus; C016532:maltoporins; D008320:Maltose; D000242:Cyclic AMP