title: Single-domain response regulator involved in the general stress response of Methylobacterium extorquens.
abstract: The general stress response of alphaproteobacteria is regulated by a partner-switching mechanism that involves the alternative sigma factor σ(EcfG), the anti-sigma factor NepR and the anti-sigma factor antagonist PhyR. To address the question of how the PhyR-NepR-σ(EcfG) cascade is activated and modulated in Methylobacterium extorquens, a forward genetic screen was applied. The screen identified the single-domain response regulator Mext_0407 as a novel regulatory element in the general stress response of M. extorquens. Analysis of phenotypes and of transcriptional fusions of PhyR-dependent genes shows that the mext_0407 deletion mutant fails to respond to various stresses. Mext_0407 requires the putative phosphorylatable aspartate-64 for its activity in vivo and genetic evidence indicates that Mext_0407 operates upstream of the PhyR-NepR-σ(EcfG) cascade.
authors.affiliation: Institute of Microbiology, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Lisa C
authors.initials: LC
authors.lastname: Metzger
authors.affiliation: Institute of Microbiology, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Anne
authors.initials: A
authors.lastname: Francez-Charlot
authors.affiliation: Institute of Microbiology, ETH Zurich, 8093 Zurich, Switzerland.
authors.forename: Julia A
authors.initials: JA
authors.lastname: Vorholt
mesh_terms: D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D020601:Methylobacterium extorquens / Q000235:genetics / Q000502:physiology*; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D014157:Transcription Factors