Laboratoire Jean Perrin, Sorbonne Université, UMR 8237, 75005 Paris, France.
Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France.
Sci Adv. 2020 Oct 7;6(41). doi: 10.1126/sciadv.abc3478. Print 2020 Oct.
It is generally accepted that prokaryotes can tune gene expression noise independently of protein mean abundance by varying the relative levels of transcription and translation. Here, we address this question quantitatively, using a custom-made library of 40 strains expressing a fluorescent protein under the control of different transcription and translation control elements. We quantify noise and mean protein abundance by fluorescence microscopy and show that for most of the natural transcription range of , expression noise is equally sensitive to variations in the transcription or translation rate because of the prevalence of extrinsic noise. In agreement, analysis of whole-genome transcriptomic and proteomic datasets suggests that noise optimization through transcription and translation tuning during evolution may only occur in a regime of weak transcription. Therefore, independent control of mean abundance and noise can rarely be achieved, which has strong implications for both genome evolution and biological engineering.
人们普遍认为，原核生物可以通过改变转录和翻译的相对水平，独立于蛋白质平均丰度来调节基因表达噪声。在这里，我们使用一个定制的 40 株菌文库来定量解决这个问题，这些菌株在不同的转录和翻译控制元件的控制下表达荧光蛋白。我们通过荧光显微镜定量测量噪声和平均蛋白质丰度，并表明对于大多数自然转录范围，由于外在噪声的普遍存在，表达噪声对转录或翻译速率的变化同样敏感。一致地，对全基因组转录组和蛋白质组数据集的分析表明，通过进化过程中的转录和翻译调节进行噪声优化可能仅发生在转录较弱的范围内。因此，平均丰度和噪声的独立控制很少能够实现，这对基因组进化和生物工程都有重要影响。
