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The chromosomal origin and terminus of replication are precisely localized in bacterial cells. We examined the cellular position of 112 individual loci that are dispersed over the circular Caulobacter crescentus chromosome and found that in living cells each locus has a specific subcellular address and that these loci are arrayed in linear order along the(More)
Correct positioning of the division plane is a prerequisite for the generation of daughter cells with a normal chromosome complement. Here, we present a mechanism that coordinates assembly and placement of the FtsZ cytokinetic ring with bipolar localization of the newly duplicated chromosomal origins in Caulobacter. After replication of the polarly located(More)
The global transcriptional regulator CtrA controls multiple events in the Caulobacter cell cycle, including the initiation of DNA replication, DNA methylation, cell division, and flagellar biogenesis. CtrA is a member of the response regulator family of two component signal transduction systems and is activated by phosphorylation. We report here that this(More)
Dividing cells must coordinate cell cycle events to ensure genetic stability. Here we identify an essential two-component signal transduction protein that controls multiple events in the Caulobacter cell cycle, including cell division, stalk synthesis, and cell cycle-specific transcription. This protein, CtrA, is homologous to response regulator(More)
Faithful chromosome segregation is an essential component of cell division in all organisms. The eukaryotic mitotic machinery uses the cytoskeleton to move specific chromosomal regions. To investigate the potential role of the actin-like MreB protein in bacterial chromosome segregation, we first demonstrate that MreB is the direct target of the small(More)
Bacteria are often highly polarized, exhibiting specialized structures at or near the ends of the cell. Among such structures are actin-organizing centers, which mediate the movement of certain pathogenic bacteria within the cytoplasm of an animal host cell; organized arrays of membrane receptors, which govern chemosensory behavior in swimming bacteria; and(More)
The master CtrA response regulator functions in Caulobacter to repress replication initiation in different phases of the cell cycle. Here, we identify an essential histidine kinase, CckA, that is responsible for CtrA activation by phosphorylation. Although CckA is present throughout the cell cycle, it moves to a cell pole in S phase, and upon cell division(More)
Bacterial replication origins move towards opposite ends of the cell during DNA segregation. We have identified a proline-rich polar protein, PopZ, required to anchor the separated Caulobacter crescentus chromosome origins at the cell poles, a function that is essential for maintaining chromosome organization and normal cell division. PopZ interacts(More)
The actin cytoskeleton represents a key regulator of multiple essential cellular functions in both eukaryotes and prokaryotes. In eukaryotes, these functions depend on the orchestrated dynamics of actin filament assembly and disassembly. However, the dynamics of the bacterial actin homolog MreB have yet to be examined in vivo. In this study, we observed the(More)
The commonly used, monomeric EYFP enabled imaging of intracellular protein structures beyond the optical resolution limit ('super-resolution' imaging) in living cells. By combining photoinduced activation of single EYFP fusions and time-lapse imaging, we obtained sub-40 nm resolution images of the filamentous superstructure of the bacterial actin protein(More)