Cooperation Between Translating Ribosomes and RNA Polymerase in Transcription Elongation

TLDR

In bacteria, RNA polymerase is typically followed by a translating ribosome during transcription of protein‑coding genes. Our in vivo data show that transcription elongation rate is tightly coupled to translation speed, with ribosome dynamics modulating RNAP velocity, preventing backtracking, and that genes with more rare codons exhibit slower transcription, thereby aligning transcription output with translational demand.

Abstract

During transcription of protein-coding genes, bacterial RNA polymerase (RNAP) is closely followed by a ribosome that translates the newly synthesized transcript. Our in vivo measurements show that the overall elongation rate of transcription is tightly controlled by the rate of translation. Acceleration and deceleration of a ribosome result in corresponding changes in the speed of RNAP. Moreover, we found an inverse correlation between the number of rare codons in a gene, which delay ribosome progression, and the rate of transcription. The stimulating effect of a ribosome on RNAP is achieved by preventing its spontaneous backtracking, which enhances the pace and also facilitates readthrough of roadblocks in vivo. Such a cooperative mechanism ensures that the transcriptional yield is always adjusted to translational needs at different genes and under various growth conditions.