Escherichia coliCreBC Is a Global Regulator of Gene Expression That Responds to Growth in Minimal Media*

We have identified nine genes, the expression of which are regulated by the CreBC two-component system: the first members of the cre regulon. They are divided into eight transcriptional units, each having a promoter-proximal TTCACnnnnnnTTCAC “cre-tag” motif. The cre regulon genes are: theackA/ptaoperon, the products of which collectively catalyze the conversion of acetyl-CoA into acetate and ATP; talA, which encodes an enzyme involved in the mobilization of glyceraldehyde-3-phosphate into the pentose phosphate pathway; radC, which encodes a RecG-like DNA recombination/repair function; malE, which is the first gene in the malEFGmaltose transporter operon;trgB, which encodes an ADP-ribose pyrophosphorylase; and three other genes, creD, yidSandyieI, the products of which have not been assigned a function. Expression of each of these cre regulon genes is induced via CreBC during growth in minimal media, with the exception ofmalE, which is more tightly repressed. The diverse functions encoded by the cre regulon suggest that CreBC is a global regulator that sits right at the heart of metabolic control inEscherichia coli.