Dataset Information

The Caulobacter crescentus smc gene is required for cell cycle progression and chromosome segregation.

ABSTRACT: The highly conserved SMC (Structural Maintenance of Chromosomes) proteins function in chromosome condensation, segregation, and other aspects of chromosome dynamics in both eukaryotes and prokaryotes. A null mutation in the Caulobacter crescentus smc gene is conditionally lethal and causes a cell cycle arrest at the predivisional cell stage. Chromosome segregation in wild-type and smc null mutant cells was examined by monitoring the intracellular localization of the replication origin and terminus by using fluorescence in situ hybridization. In wild-type cells, the origin is located at the flagellated pole of swarmer cells and, immediately after the initiation of DNA replication in stalked cells, one of the origins moves to the opposite pole, giving a bipolar localization of the origins. The terminus moves from the end of the swarmer cell opposite the origin to midcell. A subpopulation of the smc null mutant cells had mislocalized origins or termini, showing that the smc null mutation gives DNA segregation defects. Nucleoid morphology was also abnormal. Thus, we propose that the Caulobacter chromosomal origins have specific cellular addresses and that the SMC protein plays important roles in maintaining chromosome structure and in partitioning. The specific cell cycle arrest in the smc null mutant indicates the presence of a cell cycle checkpoint that senses perturbations in chromosome organization or segregation.

SUBMITTER: Jensen RB

PROVIDER: S-EPMC17939 | biostudies-literature | 1999 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The Caulobacter crescentus smc gene is required for cell cycle progression and chromosome segregation.

Jensen R B RB Shapiro L L

Proceedings of the National Academy of Sciences of the United States of America 19990901 19

The highly conserved SMC (Structural Maintenance of Chromosomes) proteins function in chromosome condensation, segregation, and other aspects of chromosome dynamics in both eukaryotes and prokaryotes. A null mutation in the Caulobacter crescentus smc gene is conditionally lethal and causes a cell cycle arrest at the predivisional cell stage. Chromosome segregation in wild-type and smc null mutant cells was examined by monitoring the intracellular localization of the replication origin and termin ...[more]

PMID: 10485882

Similar Datasets

Project description:BackgroundSecond messengers, c-di-GMP and (p)ppGpp, are vital regulatory molecules in bacteria, influencing cellular processes such as biofilm formation, transcription, virulence, quorum sensing, and proliferation. While c-di-GMP and (p)ppGpp are both synthesized from GTP molecules, they play antagonistic roles in regulating the cell cycle. In C. crescentus, c-di-GMP works as a major regulator of pole morphogenesis and cell development. It inhibits cell motility and promotes S-phase entry by inhibiting the activity of the master regulator, CtrA. Intracellular (p)ppGpp accumulates under starvation, which helps bacteria to survive under stressful conditions through regulating nucleotide levels and halting proliferation. (p)ppGpp responds to nitrogen levels through RelA-SpoT homolog enzymes, detecting glutamine concentration using a nitrogen phosphotransferase system (PTS Ntr). This work relates the guanine nucleotide-based second messenger regulatory network with the bacterial PTS Ntr system and investigates how bacteria respond to nutrient availability.ResultsWe propose a mathematical model for the dynamics of c-di-GMP and (p)ppGpp in C. crescentus and analyze how the guanine nucleotide-based second messenger system responds to certain environmental changes communicated through the PTS Ntr system. Our mathematical model consists of seven ODEs describing the dynamics of nucleotides and PTS Ntr enzymes. Our simulations are consistent with experimental observations and suggest, among other predictions, that SpoT can effectively decrease c-di-GMP levels in response to nitrogen starvation just as well as it increases (p)ppGpp levels. Thus, the activity of SpoT (or its homologues in other bacterial species) can likely influence the cell cycle by influencing both c-di-GMP and (p)ppGpp.ConclusionsIn this work, we integrate current knowledge and experimental observations from the literature to formulate a novel mathematical model. We analyze the model and demonstrate how the PTS Ntr system influences (p)ppGpp, c-di-GMP, GMP and GTP concentrations. While this model does not consider all aspects of PTS Ntr signaling, such as cross-talk with the carbon PTS system, here we present our first effort to develop a model of nutrient signaling in C. crescentus.

Dataset Information

The Caulobacter crescentus smc gene is required for cell cycle progression and chromosome segregation.

Publications

The Caulobacter crescentus smc gene is required for cell cycle progression and chromosome segregation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets