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Cell division (Cytokinesis) defines the last stage in the division cycle, in which cell constriction leads to formation of daughter cells. The molecular mechanisms responsible for this fundamental process are poorly understood for any organism. In bacteria, such as Escherichia coli, cell division occurs through the coordinated circumferential ingrowth of the cell envelope layers at the midpoint of the mother cell. Our research aims to understand at a molecular level: I) How the cell selects the correct site for cell constriction, II) How cell constriction is executed, and III) How division is coordinated with other cell cycle events such as chromosome replication and segregation. A number of genes that play key roles in one or more aspects of cytokinesis are known and biochemical activities of some of the protein products have recently been identified. Our focus is on the FtsZ protein and the products of the minicell (min) locus, MinC, D and E. Cell constriction initiates with the assembly of the FtsZ GTPase into a ring-like structure which remains associated with the leading edge of the invaginating cell wall. The Min proteins ensure selection of the correct division site by blocking formation of the FtsZ-ring at the cell poles, but not at midcell. The molecular interactions/activities of these and other relevant proteins are studied in vivo and in vitro by a variety of genetic, biochemical, biophysical and microscopic techniques.
Selected Publications
Bernhardt, T. G. and de Boer, P. A. J. (2005) SlmA, a nucleoid-associated, FtsZ binding protein required for blocking septal ring assembly over Chromosomes in E. coli. Mol. Cell 18: 555-564. [PubMed]
Bernhardt, T. G. and de Boer, P. A. J. (2004) Screening for synthetic lethal mutants in Escherichia coli and identification of EnvC (YibP) as a periplasmic septal ring factor with murein hydrolase activity. Mol. Microbiol. 52: 1255-1269. [PubMed]
Johnson, J. E., Lackner, L. L., Hale, C. A., and de Boer, P. A. J. (2004) ZipA is required for targeting of DMinC/DicB, but not DMinC/MinD, complexes to septal ring assemblies in Escherichia coli. J. Bacteriol. 186: 2418-2429. [PubMed]
Bernhardt, T. G. and de Boer, P. A. J. (2003) The Escherichia coli amidase AmiC is a periplasmic septal ring component exported via the twin-arginine transport pathway. Mol. Microbiol. 48: 1171-1182. [PubMed]
Lackner, L. L., Raskin, D. M., and de Boer, P. A. J. (2003) ATP-dependent interactions between Escherichia coli Min proteins and the phospholipid membrane in vitro. J. Bacteriol. 185: 735-749. [PubMed]
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