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DnaA couples DNA replication and the expression of two cell cycle master regulators
Justine Collier1, Sean Richard Murray, Lucy Shapiro
1Department of Developmental Biology, School of Medicine, Stanford University Medical Center, Beckman Center, Stanford, CA 94305, USA.
The EMBO Journal
|January 6, 2006
Summary
The master regulators of the Caulobacter cell cycle, CtrA and GcrA, are influenced by DnaA. This DNA replication protein activates gcrA, linking replication initiation to cell cycle progression.
Area of Science:
- Microbiology
- Molecular Biology
- Cell Biology
Background:
- Cell cycle progression in Caulobacter is regulated by CtrA and GcrA.
- CtrA and GcrA levels are inversely regulated and oscillate during the cell cycle.
Purpose of the Study:
- To investigate the role of DnaA in Caulobacter cell cycle regulation.
- To elucidate the regulatory cascade involving DnaA, GcrA, and CtrA.
Main Methods:
- Transcriptional analysis of gcrA.
- Cell cycle analysis of DnaA and GcrA protein levels.
- Investigation of proteolysis of GcrA.
Main Results:
- DnaA activates gcrA transcription.
- DnaA levels peak at replication initiation, coinciding with gcrA induction.
- Regulated proteolysis of GcrA contributes to its cell cycle variation.
- DnaA, GcrA, and CtrA form a regulatory cascade.
Conclusions:
- DnaA couples DNA replication initiation with the expression of GcrA and CtrA.
- The DnaA/GcrA/CtrA cascade drives Caulobacter cell cycle progression.