title: Combinatorial stress responses: direct coupling of two major stress responses inEscherichia coli.
abstract: Nitrogen is an essential element for all life, and this is no different for the bacterial cell. Numerous cellular macromolecules contain nitrogen, including proteins, nucleic acids and cell wall components. InEscherichia coliand related bacteria, the nitrogen stress (Ntr) response allows cells to rapidly sense and adapt to nitrogen limitation by scavenging for alternative nitrogen sources through the transcriptional activation of transport systems and catabolic and biosynthetic operons by the global transcriptional regulator NtrC. Nitrogen-starved bacterial cells also synthesize the (p)ppGpp effector molecules of a second global bacterial stress response - the stringent response. Recently, we showed that the transcription ofrelA, the gene which encodes the major (p)ppGpp synthetase inE. coli, is activated by NtrC during nitrogen starvation. Our results revealed that inE. coliand related bacteria, NtrC functions in combinatorial stress and serves to couple two major stress responses, the Ntr response and stringent response.
authors.affiliation: MRC Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ, UK.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Brown
authors.affiliation: Centre for Systems Biology and Bioinformatics, Division of Biosciences, Imperial College London, SW7 2AZ, UK.
authors.forename: Geraint
authors.initials: G
authors.lastname: Barton
authors.affiliation: MRC Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ, UK.
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Pan
authors.affiliation: Department of Life Sciences, Imperial College London, SW7 2AZ, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Buck
authors.affiliation: MRC Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ, UK.
authors.forename: Sivaramesh
authors.initials: S
authors.lastname: Wigneshweraraj
keywords: (p)ppGpp; NtrC; RNA polymerase; sigma 54; stringent response; transcription