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Monitoring Intraspecies Competition in a Bacterial Cell Population by Cocultivation of Fluorescently Labelled Strains
Published on: January 18, 2014
Multiple interactions among the competence proteins of Bacillus subtilis
Naomi Kramer1, Jeanette Hahn, David Dubnau
1Public Health Research Institute, 225 Warren Street, Newark, NJ 07103, USA.
Molecular Microbiology
|July 17, 2007
Summary
Bacterial transformation involves a polar protein complex. This complex, comprising membrane and cytosolic proteins, binds, protects, and integrates transforming DNA into the bacterial chromosome.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Genetics
Background:
- Bacterial transformation, the genetic alteration by DNA, relies on specific protein machinery.
- Proteins involved in transformation are typically membrane-associated or found in the cytosol.
- Previous studies indicated polar localization of key transformation proteins in competent Bacillus subtilis.
Purpose of the Study:
- To investigate the precise localization and interactions of proteins involved in Bacillus subtilis transformation.
- To elucidate the structural organization of the bacterial transformation complex.
- To identify the components and functions of the polar transformation machinery.
Main Methods:
- Localization studies of ComGA, ComFA, DprA, SsbB, RecA, and YjbF in competent Bacillus subtilis cells.
- Fluorescence resonance energy transfer (FRET) to assess proximity of Com proteins.
- Analysis of Com protein stability following com gene knockouts.
Main Results:
- Six key competent (Com) proteins (ComGA, ComFA, DprA, SsbB, RecA, YjbF) were found to colocalize at the cell poles.
- FRET confirmed close proximity among these six Com proteins, suggesting a functional complex.
- Com gene knockouts affected the stability of other Com proteins, supporting their interdependence.
- ComEC and ComEA were identified as additional components of the transformation complex.
- A large polar complex composed of both membrane-associated (ComGA, ComFA) and soluble (DprA, SsbB, RecA, YjbF) proteins was proposed.
Conclusions:
- A multiprotein polar complex is essential for Bacillus subtilis transformation.
- This complex binds, protects single-stranded DNA from nucleases, and facilitates its recombination.
- The findings provide a structural model for DNA uptake and integration during bacterial transformation.
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