Enhancement of cell death due to decrease in Mg2+ uptake by OmpC (cation-selective porin) deficiency in ribosome...

Area of Science:

• Microbiology
• Molecular Biology
• Cell Biology

Background:

• Ribosome modulation factor (RMF) stabilizes ribosomes during growth phase transitions in Escherichia coli.
• RMF deficiency reduces cell viability, while spermidine overaccumulation decreases both viability and RMF/OmpC synthesis.

Purpose of the Study:

• To investigate if OmpC porin deficiency exacerbates cell death caused by RMF deficiency.
• To understand the role of RMF, OmpC, and Mg2+ in maintaining cell viability during stationary phase.

Main Methods:

• Comparative analysis of single (rmf, ompC) and double (rmf ompC) mutants in Escherichia coli.
• Assessment of protein synthesis, cell viability, ribosome content, and Mg2+ levels.
• Evaluation of OmpF porin synthesis in RMF-deficient strains.

Main Results:

• The double rmf ompC mutant showed significantly reduced protein synthesis and cell viability compared to the single rmf mutant.
• A decrease in ribosome content and Mg2+ was observed in the double mutant, with partial viability restoration upon Mg2+ addition.
• RMF deficiency inhibited OmpF synthesis, leading to a combined deficiency of OmpC and OmpF in the double mutant, impacting Mg2+ uptake.

Conclusions:

• Both RMF and Mg2+ are vital for stabilizing ribosomes and ensuring cell viability in the stationary growth phase.
• The combined deficiency of OmpC and OmpF porins, alongside RMF deficiency, severely compromises cell viability due to impaired Mg2+ uptake.
• Ribosome stabilization is a key mechanism underlying the importance of RMF and Mg2+ for stationary phase survival.