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RelA inhibits Bacillus subtilis motility and chaining
Qutaiba O Ababneh1, Jennifer K Herman2
1Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA.
Journal of Bacteriology
|October 22, 2014
Summary
Nucleotide second messengers guanosine tetraphosphate and pentaphosphate [(p)ppGpp] regulate bacterial growth. In Bacillus subtilis, the RelA enzyme and (p)ppGpp levels control cell chaining and motility by influencing the SigD factor.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Physiology
Background:
- Nucleotide second messengers guanosine tetraphosphate and pentaphosphate [(p)ppGpp] are key regulators of the bacterial stringent response.
- (p)ppGpp also influences non-stringent processes like virulence, persister cell formation, and biofilm production.
- In Bacillus subtilis, (p)ppGpp synthesis is mainly controlled by RelA, YwaC, and YjbM proteins.
Purpose of the Study:
- To investigate the role of RelA and (p)ppGpp in regulating cell chaining and motility in Bacillus subtilis.
- To understand how (p)ppGpp levels affect the activity of the alternative sigma factor SigD.
- To explore the impact of basal (p)ppGpp levels on bacterial developmental decisions.
Main Methods:
- Analysis of a relA mutant in Bacillus subtilis.
- Phenotypic characterization of cell chaining and motility.
- Assessment of SigD activity under different growth conditions.
Main Results:
- A relA mutant exhibits unchained, motile cell growth.
- The relA mutant appears locked in a SigD "on" state during exponential growth.
- Basal levels of (p)ppGpp significantly influence bacterial developmental pathways.
Conclusions:
- RelA and (p)ppGpp are crucial for regulating cell chaining and motility in Bacillus subtilis, likely through modulation of SigD.
- Fine-tuning of (p)ppGpp levels plays a significant role in bacterial decision-making processes.
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