areCBA Is an Operon in Acinetobacter sp. Strain ADP1 and Is Controlled by AreR, a ς(54)-Dependent Regulator

The areCBA genes in Acinetobacter sp. strain ADP1, determining growth on benzyl alkanoates, are shown to be transcribed as a single operon and regulated by areR, which encodes a regulatory protein of the NtrC/XylR family. Assays of the Are enzymes and of two insertions of lacZ as a reporter gene have shown that the operon is induced by benzyl acetate, benzyl alcohol, and benzaldehyde, as well as 2- and 4-hydroxybenzyl acetates and benzyl propionate and butyrate. Two adjacent sites of transcriptional initiation were 97 and 96 bp upstream of the start codon for areC, near a ς(54)-dependent −12, −24 promoter. Inactivation of areR and rpoN (for RNA polymerase ς(54)) drastically reduced growth rates on the Are substrates and induction of the operon.