title: The one-component system ArnR: a membrane-bound activator of the crenarchaeal archaellum.
abstract: Linking the motility apparatus to signal transduction systems enables microbes to precisely control their swimming behaviour according to environmental conditions. Bacteria have therefore evolved a complex chemotaxis machinery, which has presumably spread through lateral gene transfer into the euryarchaeal subkingdom. By contrast Crenarchaeota encode no chemotaxis-like proteins but are nevertheless able to connect external stimuli to archaellar derived motility. This raises fundamental questions about the underlying regulatory mechanisms. Recently, we reported that the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius becomes motile upon nutrient starvation by promoting transcription of flaB encoding the filament forming subunits. Here we describe two transcriptional activators as paralogous one-component-systems Saci_1180 and Saci_1171 (ArnR and ArnR1). Deletions of arnR and arnR1 resulted in diminished flaB expression and accordingly the deletion mutants revealed impaired swimming motility. We further identified two inverted repeat sequences located upstream of the flaB core promoter of S. acidocaldarius. These cis-regulatory elements were shown to be critical for ArnR and ArnR1 mediated flaB gene expression in vivo. Finally, bioinformatic analysis revealed ArnR to be conserved not only in Sulfolobales but also in the crenarchaeal order of Desulfurococcales and thus might represent a more general control mechanism of archaeal motility.
authors: Molecular Biology of Archaea, Max Planck Institute for terrestrial Microbiology, Karl-von-Frisch-Strasse 10, 35043 Marburg, Germany.
authors: Kerstin
authors: K
authors: Lassak
authors: Eveline
authors: E
authors: Peeters
authors: Sandra
authors: S
authors: Wróbel
authors: Sonja-Verena
authors: SV
authors: Albers
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002462:Cell Membrane / Q000378:metabolism*; D019848:Gene Expression Regulation, Archaeal; D008969:Molecular Sequence Data; D009068:Movement; D005810:Multigene Family / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D016945:Sulfolobus acidocaldarius / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D019843:Archaeal Proteins; D015534:Trans-Activators