bacillus subtilis responses to stress
DESCRIPTION
Environmental stresses. Bacillus subtilis responses to stress. Competence development. Chemotaxis/motility. Sporulation. Degradation enzymes. Heat shock stress. clpC. Clp family in E. coli - degradation of many regulatory proteins. ClpC function in B. subtilis. stress. clpC. ClpC. - PowerPoint PPT PresentationTRANSCRIPT
Bacillus subtilis responses to stress
Competence development
Chemotaxis/motility
Degradation enzymes
Sporulation
Environmental stresses
Heat shock stress clpC
Clp family in E. coli - degradation of many regulatory proteins
clpC
comKClpC
ComKLate
competence genes
stress
ClpC function in
B. subtilis
SigH is also required for the transcription of many sporulation genes
RNA polymerase sigma factor H is essential for normal competence development
H H H H H H
H H
H
H H H
Exponential growth Sporulation
SigH expression in cell cycle
H
H H H H H H
H H
H
H H H
Exponential growth Sporulation
SigH half-life increases during sporulation
H
H H H H
H H
H H H
Exponential growth Sporulation
SigH half-life increases during sporulation
H
H H
H H
H H
Exponential growth Sporulation
SigH half-life increases during sporulation
H H
What needs to happen in order for ClpC to be involved in SigH expression?
ClpC has to be expressed when SigH is at the onset of sporulation
bgaBclpCA B
heat shockresponse
Integrate into chromosome
Evaluate beta-galactosidase activity in various situations
Transcriptional fusion used to detect clpC expression:
Induction of clpC expression
T0 T4
sporulation
wildtype
sigB null
spo0H null
T3.5
T3.5
>T4
clpCS (deletion mutation)
>T4
What needs to happen in order for ClpC to be involved in SigH expression?
ClpC should have an effect on SigH accumulation
ClpC has to be expressed when SigH is at the onset of sporulation
Western blot analysis of σH accumulation
T-0.5 T1 T4T0 T3T2 T-0.5 T1 T4T0 T3T2
clpC+ clpCS
Possible causes of this result:
Deficiency in active degradation of SigH
Deficiency in active transcription of spo0H
Degradation of SigH vs. Transcription of spo0H
bgaBspo0H
spo0H::bgaB fusion
No difference between spo0H expression in wildtype and clpC deletion mutant strains.
50% of SigH disappeared after 12 minutes in wildtype.
At 12 min, 85% of SigH was still present in clpCS.
SigH half-life analysis:
Because this occurred in the clpCC deletion mutant, it appears that ClpC is somehow involved in
the degradation of H.
Accumulation of SigH is due to a deficiency in its degradation.