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E. coli filament formation induced by heterologous S-layer expression.
Franziska L Lederer1, Tobias J Günther, Johannes Raff
1Institute of Radiochemistry, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.
Bioengineered Bugs
|June 4, 2011
Summary
Heterologous expression of S-layer proteins in Escherichia coli (E. coli) caused unusual cell elongation, forming filaments and tube-like structures. This indicates a novel stable cell form resulting from disordered cell division in E. coli.
Area of Science:
- Microbiology
- Molecular Biology
- Biotechnology
Background:
- Escherichia coli (E. coli) is a well-studied bacterium widely used in genetic engineering due to its rapid growth and simple requirements.
- E. coli BL21(DE3) is a common host for heterologous protein expression.
- S-layer proteins are surface proteins found in various microorganisms, often forming crystalline arrays.
Purpose of the Study:
- To investigate the heterologous expression of S-layer proteins from Lysinibacillus sphaericus JG-A12 in E. coli BL21(DE3).
- To analyze the morphological changes and cell division processes in E. coli upon expression of these S-layer proteins.
- To understand the underlying mechanisms of altered cell morphology during high-level recombinant protein production.
Main Methods:
- Heterologous expression of Lysinibacillus sphaericus JG-A12 S-layer proteins in E. coli BL21(DE3).
- Microscopic analysis (fluorescence microscopy) of E. coli cell morphology, including staining with membrane stain FM 5-95 and DAPI.
- Observation of cell division patterns and filament formation under stationary growth phase conditions.
Main Results:
- Expression of S-layer proteins induced significant cell elongation in E. coli, forming filaments exceeding 100 µm.
- Tube-like structures originating from the cell membrane were observed in E. coli filaments during the stationary growth phase.
- Disordered cell division, likely due to the high accumulation of recombinant S-layer proteins, was inferred from DAPI staining of GFP-S-layer expressing cells.
Conclusions:
- Heterologous expression of L. sphaericus S-layer proteins in E. coli leads to a novel stable cell form characterized by extreme filamentation.
- The formation of membrane-derived tubes and disordered cell division are consequences of high-level recombinant protein production in E. coli.
- Further research is needed to fully elucidate the molecular mechanisms driving these morphological changes in E. coli.
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