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Temporal controls of the asymmetric cell division cycle in Caulobacter crescentus.

Li S, Brazhnik P, Sobral B, Tyson JJ - PLoS Comput. Biol. (2009)

Bottom Line: The asymmetric cell division cycle of Caulobacter crescentus is orchestrated by an elaborate gene-protein regulatory network, centered on three major control proteins, DnaA, GcrA and CtrA.The model is validated against observed phenotypes of wild-type cells and relevant mutants, and it predicts the phenotypes of novel mutants and of known mutants under novel experimental conditions.Because the cell cycle control proteins of Caulobacter are conserved across many species of alpha-proteobacteria, the model we are proposing here may be applicable to other genera of importance to agriculture and medicine (e.g., Rhizobium, Brucella).

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.

ABSTRACT
The asymmetric cell division cycle of Caulobacter crescentus is orchestrated by an elaborate gene-protein regulatory network, centered on three major control proteins, DnaA, GcrA and CtrA. The regulatory network is cast into a quantitative computational model to investigate in a systematic fashion how these three proteins control the relevant genetic, biochemical and physiological properties of proliferating bacteria. Different controls for both swarmer and stalked cell cycles are represented in the mathematical scheme. The model is validated against observed phenotypes of wild-type cells and relevant mutants, and it predicts the phenotypes of novel mutants and of known mutants under novel experimental conditions. Because the cell cycle control proteins of Caulobacter are conserved across many species of alpha-proteobacteria, the model we are proposing here may be applicable to other genera of importance to agriculture and medicine (e.g., Rhizobium, Brucella).

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Simulation of ctrAΔ3Ω mutant.kd,ctrA2 = 0.0375 (15% of WT).
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pcbi-1000463-g006: Simulation of ctrAΔ3Ω mutant.kd,ctrA2 = 0.0375 (15% of WT).

Mentions: In our simulation of this mutant (Figure 6), CtrA and CtrA∼P fluctuate in a manner similar to wt cells. Notice that the steady state levels of CtrA and CtrA∼P during DNA synthesis phase are about 10-fold higher in the mutant than in wt cells because the degradation rate of CtrA (and CtrA∼P) protein 10-fold smaller in the mutants. Nevertheless, CtrA proteolysis is still sufficient to permit DNA synthesis. Later in the cell cycle, during the ∼50 min when the ctrA gene is hemimethylated and CtrA proteolysis is minimal, both wt cells and mutant cells accumulate nearly the same amount of CtrA and CtrA∼P. Hence, the mutant cell undergoes normal division cycle.


Temporal controls of the asymmetric cell division cycle in Caulobacter crescentus.

Li S, Brazhnik P, Sobral B, Tyson JJ - PLoS Comput. Biol. (2009)

Simulation of ctrAΔ3Ω mutant.kd,ctrA2 = 0.0375 (15% of WT).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2714070&req=5

pcbi-1000463-g006: Simulation of ctrAΔ3Ω mutant.kd,ctrA2 = 0.0375 (15% of WT).
Mentions: In our simulation of this mutant (Figure 6), CtrA and CtrA∼P fluctuate in a manner similar to wt cells. Notice that the steady state levels of CtrA and CtrA∼P during DNA synthesis phase are about 10-fold higher in the mutant than in wt cells because the degradation rate of CtrA (and CtrA∼P) protein 10-fold smaller in the mutants. Nevertheless, CtrA proteolysis is still sufficient to permit DNA synthesis. Later in the cell cycle, during the ∼50 min when the ctrA gene is hemimethylated and CtrA proteolysis is minimal, both wt cells and mutant cells accumulate nearly the same amount of CtrA and CtrA∼P. Hence, the mutant cell undergoes normal division cycle.

Bottom Line: The asymmetric cell division cycle of Caulobacter crescentus is orchestrated by an elaborate gene-protein regulatory network, centered on three major control proteins, DnaA, GcrA and CtrA.The model is validated against observed phenotypes of wild-type cells and relevant mutants, and it predicts the phenotypes of novel mutants and of known mutants under novel experimental conditions.Because the cell cycle control proteins of Caulobacter are conserved across many species of alpha-proteobacteria, the model we are proposing here may be applicable to other genera of importance to agriculture and medicine (e.g., Rhizobium, Brucella).

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.

ABSTRACT
The asymmetric cell division cycle of Caulobacter crescentus is orchestrated by an elaborate gene-protein regulatory network, centered on three major control proteins, DnaA, GcrA and CtrA. The regulatory network is cast into a quantitative computational model to investigate in a systematic fashion how these three proteins control the relevant genetic, biochemical and physiological properties of proliferating bacteria. Different controls for both swarmer and stalked cell cycles are represented in the mathematical scheme. The model is validated against observed phenotypes of wild-type cells and relevant mutants, and it predicts the phenotypes of novel mutants and of known mutants under novel experimental conditions. Because the cell cycle control proteins of Caulobacter are conserved across many species of alpha-proteobacteria, the model we are proposing here may be applicable to other genera of importance to agriculture and medicine (e.g., Rhizobium, Brucella).

Show MeSH
Related in: MedlinePlus