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Selective cell cycle transcription requires membrane synthesis in Caulobacter
A K Brassinga1, B Gorbatyuk, M C Ouimet
1Department of Microbiology and Immunology, McGill University, 3775 University Street, Montreal, Quebec, Canada H3A 2B4.
The EMBO Journal
|February 17, 2000
Summary
Blocking membrane synthesis in Caulobacter crescentus impacts cell division by affecting transcription of key genes. This suggests a feedback mechanism linking membrane production to cellular processes like flagellar assembly and DNA replication.
Area of Science:
- Microbiology
- Cell Biology
- Molecular Biology
Background:
- Caulobacter crescentus exhibits asymmetric cell division, producing distinct daughter cells with specialized polar membrane surfaces.
- This asymmetry is crucial for cell cycle progression and differentiation.
Purpose of the Study:
- To investigate the relationship between membrane synthesis and transcriptional regulation in Caulobacter crescentus.
- To determine how blocking membrane synthesis affects the transcription of genes involved in cell division and associated processes.
Main Methods:
- Caulobacter crescentus cultures were subjected to conditions that blocked membrane synthesis.
- Transcriptional activity of various promoters, including sigma-54-dependent, CtrA-dependent, ccrM, che, and replication origin promoters, was analyzed.
Main Results:
- Blocked membrane synthesis completely inhibited transcription from sigma-54-dependent flagellar, ccrM, and che promoters.
- Transcription from CtrA-dependent flagellar promoters was reduced but activated, while transcription at the chromosome replication origin was initially inhibited then induced.
- Selective promoter activity suggests a feedback loop coupling membrane synthesis to specific cellular functions.
Conclusions:
- Membrane synthesis is tightly coupled to transcriptional regulation in Caulobacter crescentus.
- This feedback mechanism prioritizes transcription for membrane-associated processes like flagellar assembly, chemosensory system biogenesis, and chromosome replication.