MOLECULAR CHARACTERIZATION OF ADIY, A REGULATORY GENE WHICH AFFECTS EXPRESSION OF THE BIODEGRADATIVE ACID-INDUCED ARGININE DECARBOXYLASE GENE (ADIA) OF ESCHERICHIA-COLI

A transcriptional regulator gene, designated adiY, was found downstrea m of the biodegradative arginine decarboxylase (adiA) gene (previously known as adi) of Escherichia coli, The arginine decarboxylase system is maximally induced under conditions of acidic ph, anaerobiosis and r ich medium, and AdiY was found to increase the expression of adiA. The DNA sequence of adiY encodes a protein of 253 amino acids. Primer ext ension analysis defined the promoter. The amino acid sequence of AdiY showed homology to the XylS/AraC family of transcriptional regulators, which includes EnvY and AppY. Studies suggested that sequences requir ed for acid induction were also necessary to observe the stimulation b y AdiY. An examination of the substitution of AdiY, AppY and EnvY show ed that these three proteins can, to some extent, stimulate the other systems.