DksA potentiates direct activation of amino acid promoters by ppGpp.

ABSTRACT: Amino acid starvation in Escherichia coli results in a spectrum of changes in gene expression, including inhibition of rRNA and tRNA promoters and activation of certain promoters for amino acid biosynthesis and transport. The unusual nucleotide ppGpp plays an important role in both negative and positive regulation. Previously, we and others suggested that positive effects of ppGpp might be indirect, resulting from the inhibition of rRNA transcription and, thus, liberation of RNA polymerase for binding to other promoters. Recently, we showed that DksA binds to RNA polymerase and greatly enhances direct effects of ppGpp on the negative control of rRNA promoters. This conclusion prompted us to reevaluate whether ppGpp might also have a direct role in positive control. We show here that ppGpp

SUBMITTER: Paul BJ 

PROVIDER: S-EPMC1142371 | biostudies-literature | 2005 May

REPOSITORIES: biostudies-literature