Characterization of ftsZ mutations that render Bacillus subtilis resistant to MinC

• Published in: PloS one Vol. 5; no. 8; p. e12048
• Main Authors: de Oliveira, Inês Filipa Fernandes, de Sousa Borges, Anabela, Kooij, Viola, Bartosiak-Jentys, Jeremy, Luirink, Joen, Scheffers, Dirk-Jan
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 11-08-2010; Public Library of Science (PLoS)
• Subjects: Bacillus subtilis; Bacillus subtilis - cytology; Bacillus subtilis - genetics; Bacillus subtilis - metabolism; Bacteria; Bacterial Proteins - antagonists & inhibitors; Bacterial Proteins - biosynthesis; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biochemistry; Biochemistry/Macromolecular Assemblies and Machines; Cell Division; Cloning; Cytoskeletal Proteins - antagonists & inhibitors; Cytoskeletal Proteins - chemistry; Cytoskeletal Proteins - genetics; Cytoskeletal Proteins - metabolism; Deoxyribonucleic acid; DNA; E coli; Enzymes; Escherichia coli; Genetic aspects; Genetic screening; Genetic testing; Gram-negative bacteria; Gram-positive bacteria; Guanosine triphosphate; Hydrolysis; Laboratories; Lymphocytes B; Microbiology; Microbiology/Microbial Growth and Development; Mutants; Mutation; Nucleoids; Occlusion; Polymerization; Protein Multimerization; Protein Structure, Quaternary; Proteins; Proteomics; Netherlands
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0012048

Cell division in Bacillus subtilis occurs precisely at midcell. Positional control of cell division is exerted by two mechanisms: nucleoid occlusion, through Noc, which prevents division through nucleoids, and the Min system, where the combined action of the MinC, D and J proteins prevents formation of the FtsZ ring at cell poles or recently completed division sites.
We used a genetic screen to identify mutations in ftsZ that confer resistance to the lethal overexpression of the MinC/MinD division inhibitor. The FtsZ mutants were purified and found to polymerize to a similar or lesser extent as wild type FtsZ, and all mutants displayed reduced GTP hydrolysis activity indicative of a reduced polymerization turnover. We found that even though the mutations conferred in vivo resistance to MinC/D, the purified FtsZ mutants did not display strong resistance to MinC in vitro.
Our results show that in B. subtilis, overproduction of MinC can be countered by mutations that alter FtsZ polymerization dynamics. Even though it would be very likely that the FtsZ mutants found depend on other Z-ring stabilizing proteins such as ZapA, FtsA or SepF, we found this not to be the case. This indicates that the cell division process in B. subtilis is extremely robust.