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CsgA, an extracellular protein essential for Myxococcus xanthus development
1Department of Microbiology, University of Georgia, Athens 30602.
Journal of Bacteriology
|September 1, 1990
Summary
Myxococcus xanthus mutants lacking the CsgA protein are deficient in producing an essential extracellular molecule. This CsgA protein is crucial for bacterial development and may function as a pheromone.
Area of Science:
- Microbiology
- Molecular Biology
- Developmental Biology
Background:
- Myxococcus xanthus exhibits complex developmental behaviors.
- Extracellular molecules play a role in bacterial development.
Purpose of the Study:
- To investigate the function and cellular location of the CsgA protein in Myxococcus xanthus development.
- To determine if CsgA is an extracellular molecule essential for development.
Main Methods:
- Utilized immunological probes and a lacZ-csgA translational gene fusion in E. coli to produce and purify CsgA protein.
- Employed affinity-purified polyclonal antibodies for colloidal gold labeling and transmission electron microscopy to locate native CsgA.
- Assessed the effect of anti-CsgA antibodies on wild-type M. xanthus development.
Main Results:
- Detected 1,100–2,200 extracellular CsgA molecules per cell, primarily in the extracellular matrix.
- Demonstrated that anti-CsgA antibodies inhibit wild-type development, with inhibition reversed by neutralizing the antibodies with CsgA fusion protein.
- Confirmed that the csgA gene encodes a 17.7-kilodalton polypeptide.
Conclusions:
- The CsgA gene product is an essential extracellular molecule in Myxococcus xanthus development.
- CsgA is localized to the extracellular matrix and likely functions as a developmental signaling molecule or pheromone.