GcvA-mediated activation of gcvT-lacZ expression involves the carboxy-terminal domain of the alpha subunit of RNA polymerase

Several LysR-type transcriptional regulators have been shown to require the carboxy-terminal domain of the alpha subunit (alpha CTD) of RNA polymerase to activate their target genes. We show here that GcvA, a LysR-type protei n, also uses the alpha CTD to activate the Escherichia coli gcvTHP operon. Amino acid residues in the alpha CTD important for GcvA-dependent activatio n, however, have no effect on GcvA-mediated repression bf the operon. (C) 1 999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.