Format

Send to

Choose Destination
J Bacteriol. 2017 Jun 27;199(14). pii: e00212-17. doi: 10.1128/JB.00212-17. Print 2017 Jul 15.

A Mutation in the Bacillus subtilis rsbU Gene That Limits RNA Synthesis during Sporulation.

Author information

1
Graduate Program in Molecular Biology, Tufts University School of Medicine, Boston, Massachusetts, USA.
2
Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA.
3
Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA linc.sonenshein@tufts.edu.

Abstract

Mutants of Bacillis subtilis that are temperature sensitive for RNA synthesis during sporulation were isolated after selection with a 32P suicide agent. Whole-genome sequencing revealed that two of the mutants carried an identical lesion in the rsbU gene, which encodes a phosphatase that indirectly activates SigB, the stress-responsive RNA polymerase sigma factor. The mutation appeared to cause RsbU to be hyperactive, because the mutants were more resistant than the parent strain to ethanol stress. In support of this hypothesis, pseudorevertants that regained wild-type levels of sporulation at high temperature had secondary mutations that prevented expression of the mutant rsbU gene. The properties of these RsbU mutants support the idea that activation of SigB diminishes the bacterium's ability to sporulate.IMPORTANCE Most bacterial species encode multiple RNA polymerase promoter recognition subunits (sigma factors). Each sigma factor directs RNA polymerase to different sets of genes; each gene set typically encodes proteins important for responses to specific environmental conditions, such as changes in temperature, salt concentration, and nutrient availability. A selection for mutants of Bacillus subtilis that are temperature sensitive for RNA synthesis during sporulation unexpectedly yielded strains with a point mutation in rsbU, a gene that encodes a protein that normally activates sigma factor B (SigB) under conditions of salt stress. The mutation appears to cause RsbU, and therefore SigB, to be active inappropriately, thereby inhibiting, directly or indirectly, the ability of the cells to transcribe sporulation genes.

KEYWORDS:

Bacillus subtilis; RsbU; sigma factor B; sporulation

PMID:
28461450
PMCID:
PMC5494743
DOI:
10.1128/JB.00212-17
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center