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Does RNA polymerase help drive chromosome segregation in bacteria?
Jonathan Dworkin1, Richard Losick
1Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Summary
Bacterial chromosome segregation relies on RNA polymerase, a molecular motor. Inhibiting RNA polymerase prevents duplicated DNA separation, suggesting its role in bacterial cell division.
Area of Science:
- Microbiology
- Molecular Biology
- Cell Biology
Background:
- Bacteria segregate chromosomes without a mitotic apparatus.
- Chromosome replication initiates bidirectionally from a single origin (oriC).
- Origin regions move poleward during the cell cycle, but the driving motor is unknown.
Purpose of the Study:
- To investigate the role of RNA polymerase as a motor for bacterial chromosome segregation.
- To determine if transcription contributes to the separation of replicating chromosomes.
Main Methods:
- Utilized fluorescence microscopy in living Bacillus subtilis cells.
- Observed the effect of RNA polymerase inhibitors on DNA separation.
Main Results:
- Inhibiting RNA polymerase significantly impeded the separation of newly duplicated DNAs near the replication origin.
- This suggests that the force generated by RNA polymerase is crucial for chromosome movement.
Conclusions:
- RNA polymerase acts as a molecular motor contributing to bacterial chromosome segregation.
- The biased orientation of genes away from oriC, coupled with transcription-driven forces, likely drives chromosome separation.