A Genetic Oscillator and the Regulation of Cell Cycle Progression in Caulobacter crescentus

Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA.
Cell cycle (Georgetown, Tex.) (Impact Factor: 4.57). 11/2004; 3(10):1252-4. DOI: 10.4161/cc.3.10.1181
Source: PubMed


Analyses of cell polarity, division, and differentiation in prokaryotes have identified several regulatory proteins that exhibit dramatic changes in expression and spatial localization over the course of a cell cycle. The dynamic behavior of these proteins is often intrinsically linked to their function as polarity determinants.(1-3) In the alpha-proteobacterium, Caulobacter crescentus, the CtrA global transcriptional regulator exhibits a spatially and temporally dynamic expression pattern across the cell cycle. CtrA plays key roles in asymmetric cell division and in the timing of chromosome replication.(3,4) An additional global regulator, GcrA, has recently been discovered that both regulates and is regulated by CtrA.(5) Together, these regulatory proteins create a genetic circuit in which the cellular concentrations of CtrA and GcrA oscillate spatially and temporally to control daughter cell differentiation and cell cycle progression.

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    • "GcrA could interact directly with the promoter DNA or alternatively, could interact with a protein bound to the promoter DNA. Since GcrA lacks any detectable functional motifs, if an interaction with DNA occurs it is likely to be via a novel mechanism (Crosson et al., 2004). If GcrA does not interact directly with DNA, the mechanism of transcriptional regulation by this protein is likely to be novel. "
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    ABSTRACT: Caulobacter crescentus has become the predominant bacterial model system to study the regulation of cell-cycle progression. Stage-specific processes such as chromosome replication and segregation, and cell division are coordinated with the development of four polar structures: the flagellum, pili, stalk, and holdfast. The production, activation, localization, and proteolysis of specific regulatory proteins at precise times during the cell cycle culminate in the ability of the cell to produce two physiologically distinct daughter cells. We examine the recent advances that have enhanced our understanding of the mechanisms of temporal and spatial regulation that occur during cell-cycle progression.
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