Département de biochimie, de microbiologie et de bio-informatique, Faculté des sciences et de génie, Université Laval, Québec, Québec, Canada.
Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, Québec, Canada.
PLoS Genet. 2023 May 26;19(5):e1010756. doi: 10.1371/journal.pgen.1010756. eCollection 2023 May.
How changes in the different steps of protein synthesis-transcription, translation and degradation-contribute to differences of protein abundance among genes is not fully understood. There is however accumulating evidence that transcriptional divergence might have a prominent role. Here, we show that yeast paralogous genes are more divergent in transcription than in translation. We explore two causal mechanisms for this predominance of transcriptional divergence: an evolutionary trade-off between the precision and economy of gene expression and a larger mutational target size for transcription. Performing simulations within a minimal model of post-duplication evolution, we find that both mechanisms are consistent with the observed divergence patterns. We also investigate how additional properties of the effects of mutations on gene expression, such as their asymmetry and correlation across levels of regulation, can shape the evolution of paralogs. Our results highlight the importance of fully characterizing the distributions of mutational effects on transcription and translation. They also show how general trade-offs in cellular processes and mutation bias can have far-reaching evolutionary impacts.
蛋白质合成的各个步骤（转录、翻译和降解）的变化如何导致基因之间蛋白质丰度的差异尚不完全清楚。然而，越来越多的证据表明转录分歧可能起着突出的作用。在这里，我们表明酵母的同源基因在转录上比在翻译上更为多样化。我们探索了这种转录分歧优势的两个因果机制：基因表达的精确性和经济性之间的进化权衡，以及转录的更大突变靶标大小。在一个最小的复制后进化模型中进行模拟，我们发现这两个机制都与观察到的分歧模式一致。我们还研究了突变对基因表达的影响的其他特性，如它们在调控水平上的不对称性和相关性，如何塑造同源基因的进化。我们的结果强调了充分描述转录和翻译中突变效应分布的重要性。它们还表明，细胞过程和突变偏向的一般权衡如何产生深远的进化影响。
