Rotter, Christine and Muehlbacher, Susanne and Salamon, Daniel and Schmitt, Ruediger and Scharf, Birgit (2006) Rem, a new transcriptional activator of motility and chemotaxis in Sinorhizobium meliloti. JOURNAL OF BACTERIOLOGY, 188 (19). pp. 6932-6942. ISSN 0021-9193,
Full text not available from this repository. (Request a copy)Abstract
The expression of 51 known genes clustered in the flagellar regulon of Sinorhizobium meliloti is organized as a three-class hierarchy: class IA comprises the master regulatory genes, visN and visR; class 11, controlled by VisNR, comprises flagellar assembly and motility genes; and class III comprises flagellin and chemotaxis genes requiring class II for expression. The expression of visN-visR is constitutive throughout growth, whereas that of class II and class III genes is limited to exponential growth. A new OmpR-like, 25-kDa transcription factor, Rem, whose synthesis is confined to exponential growth, was shown to positively control swimming motility. No phosphorylation of the receiver domain of Rem was required for its activity. Gene expression in tester strains with known deficiencies placed the rem gene (class IB) below visN-visR (class IA) and above class 11 genes in the regulatory cascade. Footprinting analysis demonstrated that the Rem protein binds to class II gene promoters as well as to its own promoter, indicating that this protein is autoregulatory. An alignment of the Rem-protected DNA sequences revealed a conserved binding motif of imperfect tandem repeats overlapping a predicted -35 promoter box by 3 bp. This new promoter was confirmed by mapping the transcription start site of a typical class II gene,flgB, 5 nucleotides downstream of the -10 promoter box. The transcription of rem is under dual control of an upstream (Rem-activated) class II-type promoter and a downstream (VisNR-activated) sigma(70)-like promoter. The central role of Rem as the growth-dependent transcriptional activator intermediate between the master regulator, VisNR, and the flagellar and motility genes is a new distinguishing feature of the S. meliloti regulatory cascade.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | RHIZOBIUM-LUPINI H13-3; GRAM-NEGATIVE BACTERIA; CELL-CYCLE PROGRESSION; SIGNAL-TRANSDUCTION; RESPONSE REGULATOR; CONSERVED ASPARTATE; HELICOBACTER-PYLORI; MUTATIONAL ANALYSIS; FLAGELLAR FILAMENT; EXPRESSION; |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 25 Jan 2021 09:31 |
| Last Modified: | 25 Jan 2021 09:31 |
| URI: | https://pred.uni-regensburg.de/id/eprint/33948 |
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