DataSheet2_On translational control by ribosome speed in S. cerevisiae.PDF

Introduction: In addition to the widespread and well documented control of protein synthesis by translation initiation, recent evidence suggests that translation elongation can also control protein synthesis rates. One of the proposed mechanisms leading to elongation control is the interference of slow ribosome movement around the start codon with efficient translation initiation. Here we estimate the frequency with which this mode of control occurs in baker’s yeast growing in rich medium.Methods: We interrogate published genome-wide datasets for evidence of transcripts associated with queueing small ribosomal subunits, and confirm results from these surveys using additional experimental work.Results: Our analyses reveal that transcripts from around 20% of yeast genes show evidence of queueing ribosomes, which may be indicative of translation elongation control. Moreover, this subset of transcripts is sensitive to distinct regulatory signals compared to initiation-controlled mRNAs, and such distinct regulation occurs, for example, during the response to osmotic stress.Discussion: Our analyses provide a first quantitative estimate for the prevalence of translational control exerted via the elongation stage in a commonly used model organism, and suggest that transcript under elongation control form a separately addressable RNA regulon.

引言：除了广泛且记录详尽的通过翻译起始对蛋白质合成的控制外，近期的研究证据表明，翻译延伸阶段亦能调控蛋白质合成的速率。导致延伸控制的一种假说机制是，缓慢的核糖体在起始密码子周围的移动干扰了高效的翻译起始。在本研究中，我们估算在富含培养基中生长的酿酒酵母中，这种控制模式的频率。方法：我们通过分析已发表的基因组广域数据集，寻找与排队的小型核糖体亚单位相关的转录本证据，并使用额外的实验工作验证这些调查的结果。结果：我们的分析揭示，约20%的酵母基因的转录本显示出排队核糖体的证据，这可能是翻译延伸控制的指标。此外，与起始控制的mRNA相比，此子集的转录本对不同的调控信号敏感，例如在渗透压应激反应期间，这种不同的调控现象发生。讨论：我们的分析为在常用模式生物中通过延伸阶段施加的翻译控制的普遍性提供了首次定量估计，并暗示处于延伸控制下的转录本形成了一个可单独处理的RNA调控子集。