DNA replication initiation is required for mid-cell positioning of FtsZ rings in Caulobacter crescentus.
Mol Microbiol
; 45(3): 605-16, 2002 Aug.
Article
in En
| MEDLINE
| ID: mdl-12139609
ABSTRACT
Polymerization of the GTPase FtsZ to form a structure called the Z-ring is the earliest known step in bacterial cell division. Mid-cell Z-ring assembly coincides with the beginning of the replication cycle in the differentiating bacterium Caulobacter crescentus. Z-ring disassembly occurs at the end of the division cycle, resulting in the complete degradation of FtsZ from both stalked and swarmer progeny cells. New Z-rings can only form in the replicative stalked cell. Conditional mutants in DNA replication were used to determine what role DNA replication events play in the process of Z-ring assembly at different stages in the cell cycle. Z-ring assembly occurred even when early stages of DNA replication were blocked; however, the Z-rings were localized at a subpolar region of the cell. Z-rings only assembled at the proper mid-cell location if DNA replication had initiated. Z-ring assembly coincided with areas containing little or no DNA, and Z-rings could not form over an unreplicated chromosome. Overexpressed FtsZ in the absence of DNA replication did not stimulate productive mid-cell Z-ring assembly but, instead, caused the ends of cells to constrict over an extended area away from the nucleoid. These results indicate that the state of chromosome replication is a major determinant of Z-ring localization in Caulobacter.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacterial Proteins
/
DNA, Bacterial
/
Caulobacter crescentus
/
Cytoskeletal Proteins
/
DNA Replication
Language:
En
Journal:
Mol Microbiol
Year:
2002
Document type:
Article