Bacillus subtilis remains translationally active after CRISPRi-mediated replication initiation arrest

Area of Science:

• Microbiology
• Molecular Biology
• Bacterial Genetics

Background:

• Bacterial DNA replication initiates at oriC, involving DnaA protein binding to DnaA boxes.
• Replication control is crucial during development and stress, impacting bacterial survival and adaptation.
• Understanding non-replicating states is key to bacterial persistence, dormancy, and environmental adjustment.

Purpose of the Study:

• To investigate the physiological and molecular outcomes of halting bacterial DNA replication initiation.
• To precisely block DnaA binding to oriC without affecting other DnaA functions.
• To analyze the effects of early replication arrest on Bacillus subtilis.

Main Methods:

• Utilized clustered regularly interspaced short palindromic repeats interference (CRISPRi) in Bacillus subtilis.
• Targeted specific DnaA boxes (6 and 7) within the oriC region to prevent DnaA binding.
• Monitored cell growth, translation, and stress responses (SOS response) after replication arrest.

Main Results:

• Successfully arrested DNA replication initiation by specifically blocking DnaA binding to oriC.
• Observed continued cell growth and translation in non-replicating cells.
• Demonstrated that this specific replication arrest did not trigger a global SOS response.

Conclusions:

• Precise inhibition of replication initiation is achievable using CRISPRi targeting DnaA boxes.
• Bacillus subtilis can maintain growth and translation while arrested from replication.
• This method provides a valuable tool for studying bacterial non-replicating phenotypes and adaptive strategies.