Isolation und Charakterisierung der sporulationsspezifischen Protease LonB von Bacillus subtilis
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Philipps-Universität Marburg
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Abstract
The use of proteases for the regulation of
physiological and regulatory processes in Microorganisms is a
widely distributed phenomenon. Most of all proteolytic
breakdown is dependent on the energetic status of the cell. The
genome of Bacillus subtilis codes for two members of the family
of ATP-dependent Serine proteases.The synthesis of the first
one,which is LonA, increases in response to heat stress,
ethanol, osmotic and oxidative stress and after treatment with
puromycin. Furthermore a role in the negative regulation of
SigA-activity under non sporulation inducing conditions is
suspected. The gen of the second protease, lonB, is located
immediately upstream of lonA. This study shows that
transcription of lonB is controlled by the first forespore
specific sigma factor, SigF, and that it?s expression is
restricted to that compartment. DNA-array analysis of cells
after artificial induction of sigF expression revealed a
significant increase of the amount of lonB transcript and
Northern analysis showed a monocystronic transcript.
Flourescence of strains carrying a lonb-GFP fusion was
exclusively detected in the forespore and depended on the
presence of the transcription factor SigF. Transcription was
initiated at a specific start point that was identified by
primer extension analysis and that is located downstream of
sequences similar to known sigF dependent sequences. Both LonB
and LonA were proven to be present in crude cell extracts using
specific polyclonal antibodies. LonB appeared 90 min after
onset of sporulation, whereas LonA could be found allready
during vegetative growth. In vitro both peptidase and
ATP-dependent protease activity could be demonstrated for both
enzymes, and an associated ATPase activity is very likely.
Inactivation of lonA and lonB by insertion showed no effect on
the phenotype of vegetative and sporulating cells, and
transcription of genes controlled by the sporulation sigma
factors SigF, SigG and SigK was not affected in a lonB-mutant.
Comparative 2D-gel analysis of wildtype and lon-mutants lead to
the assumption that LonB may influence the ammount of the
mothercell specific serin protein kinase PrkA, but as LonB and
PrkA are restricted to different compartments the effect may be
indirect.
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Dates
Created: 2003Issued: 2004-01-22Updated: 2011-08-10
Faculty
Fachbereich Biologie
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
Bacillus subtilus, Lon-proteasesBacillus subtilis, Lon-Proteasen
DFG-subjects
Proteasen
DDC-Numbers
570
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Hövel, Sven (128700882): Isolation und Charakterisierung der sporulationsspezifischen Protease LonB von Bacillus subtilis. : Philipps-Universität Marburg 2004-01-22. DOI: https://doi.org/10.17192/z2004.0068.
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This item has been published with the following license: In Copyright