Control of ribosome synthesis in bacteria: the important role of rRNA chain elongation rate

摘要

Bacteria growth depends crucially on protein synthesis, which is limited by ribosome synthesis. Ribosomal RNA (rRNA) transcription is the rate-limiting step of ribosome synthesis. It is generally proposed that the transcriptional initiation rate of rRNA operon is the primary factor that controls the rRNA synthesis. In this study, we established a convenient GFP-based reporter approach for measuring the bacterial rRNA chain elongation rate. We showed that the rRNA chain elongation rate ofEscherichia coliremains constant under nutrient limitation and chloramphenicol inhibition. In contrast, rRNA chain elongation rate decreases dramatically under low temperatures. Strikingly, we found thatVibrio natriegens, the fastest growing bacteria known, has a 50% higher rRNA chain elongation rate thanE. coli, which contributes to its rapid ribosome synthesis. Our study demonstrates that rRNA chain elongation rate is another important factor that affects the bacterial ribosome synthesis capacity.

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