title: Negative regulation of adenylate cyclase gene (cya) expression by cyclic AMP-cyclic AMP receptor protein in Escherichia coli: studies with cya-lac protein and operon fusion plasmids.
abstract: We constructed cya-lac protein and operon fusion plasmids in vitro. The effect of cyclic AMP (cAMP) on cya expression was examined by measuring the synthesis of beta-galactosidase in Escherichia coli cells containing fused plasmids. In the cya-lacZ fused protein system, cya expression was strongly repressed by exogenous cAMP. Functional cAMP receptor protein (CRP) was necessary for this effect. On the other hand, in a tet-lacZ fused protein as a control system, tet expression was not affected by cAMP. The inhibition of cya expression by cAMP was also observed in the cya-lac fused operon system, although it was necessary to increase the amount of cAMP or CRP in the cells to detect the effect. The results indicate that cAMP-CRP is a negative regulator of cya expression at the level of transcription.
mesh_terms: D000262:Adenylyl Cyclases / Q000096:biosynthesis / Q000235:genetics*; D000242:Cyclic AMP / Q000494:pharmacology*; D004274:DNA, Recombinant; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005798:Genes, Bacterial; D009876:Operon; D010957:Plasmids; D011953:Receptors, Cyclic AMP / Q000494:pharmacology* / Q000502:physiology; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000096:biosynthesis
chemical_list: D004274:DNA, Recombinant; D011953:Receptors, Cyclic AMP; D000242:Cyclic AMP; D001616:beta-Galactosidase; D000262:Adenylyl Cyclases