Park Soojin, Yang Jina, Yang Sora, Han Yong Hee, Kim Giho, Seo Sang Woo, Lee Nam Ki
Department of Chemistry, Seoul National University, Seoul 08826, Korea.
Department of Chemical and Biological Engineering, Jeju National University, Jeju 63243, Korea.
Nucleic Acids Res. 2025 Sep 5;53(17). doi: 10.1093/nar/gkaf896.
The functional coupling of transcription and translation contributes significantly to maintaining messenger RNA (mRNA) expression in bacterial cells. Premature transcription termination and fast mRNA decay are known to limit the expression of mRNAs when transcription is decoupled from translation. Here, we report that inhibiting the generation of untranslatable mRNAs from the promoter-proximal region is a newly identified but essential pathway of mRNA quality control by transcription-translation decoupling. The promoter-proximal region of mRNAs, the amount of which reflects early transcription in the 5'-untranslated region, is not generated without translation. The decoupling between transcription and translation results in RNA polymerase (RNAP) traffic within 250 bp from the transcription start site, hindering productive early transcription. The limited processivity of RNAP without a coupled ribosome in the promoter-proximal region is further supported by the observation that decoupled RNAP elongates mRNA by only 80-90 bp on average in vivo. Our results demonstrate that ribosome coupling near the promoter-proximal region is critical for the efficient synthesis of translatable mRNAs by RNAPs.
转录与翻译的功能偶联对维持细菌细胞中信使核糖核酸（mRNA）的表达起着重要作用。当转录与翻译解偶联时，已知过早的转录终止和快速的mRNA降解会限制mRNA的表达。在此，我们报告称，抑制从启动子近端区域产生不可翻译的mRNA是一种新发现的、但通过转录-翻译解偶联进行mRNA质量控制的重要途径。mRNA的启动子近端区域在没有翻译的情况下不会产生，其数量反映了5'非翻译区的早期转录情况。转录与翻译的解偶联导致RNA聚合酶（RNAP）在距转录起始位点250 bp范围内移动，阻碍了有效的早期转录。在启动子近端区域没有偶联核糖体的情况下RNAP的有限持续性，进一步得到了如下观察结果的支持：在体内，解偶联的RNAP平均仅使mRNA延伸80 - 90 bp。我们的结果表明，启动子近端区域附近的核糖体偶联对于RNAP高效合成可翻译的mRNA至关重要。
