Cyclic AMP-dependent expression of the Escherichia coli serC-aroA operon.
The Escherichia coli serC-aroA operon encodes biosynthetic enzymes for unrelated amino acid biosynthetic pathways leading to the synthesis of serine and the aromatic amino acids. A serC-aroA-lac translational fusion was constructed in the vector pMC1403. Synthesis of beta-galactosidase from the serC-aroA-lac fusion was found to be enhanced in the presence of lactose as the sole carbon source. This enhancement was not observed in strains containing a cya or crp mutant. However, the exogenous addition of cAMP greatly increased the beta-galactosidase synthesis in the cya mutant strain. The serC-aroA mRNA content, analyzed by a dot blot assay, also appeared to increase in the serC+ aroA+ cells after the exogenous addition of cAMP. These findings unambiguously indicate that the expression of the serC-aroA operon is positively controlled by cAMP.
Department of Biochemistry, Kangwon National University, South Korea.
C J
CJ
Lim
W
W
Hwang
E H
EH
Park
J A
JA
Fuchs
D001483:Base Sequence; D000242:Cyclic AMP / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D010957:Plasmids; D012333:RNA, Messenger / Q000032:analysis; D011994:Recombinant Proteins / Q000096:biosynthesis; D001616:beta-Galactosidase / Q000096:biosynthesis
D012333:RNA, Messenger; D011994:Recombinant Proteins; D000242:Cyclic AMP; D001616:beta-Galactosidase