DataSheet1_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：除了蛋白质合成调控的广泛且详尽的翻译起始控制之外，近期的研究证据表明，翻译延伸过程同样可以调控蛋白质合成的速率。所提出的导致延伸调控的一种机制是，在起始密码子周围，缓慢的核糖体移动对高效翻译起始的干扰。在本研究中，我们评估了这种调控模式在富含培养基中生长的酵母菌中发生的频率。方法：我们通过分析已发表的基因组范围数据集，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证实了这些调查结果。结果：我们的分析揭示，大约20%的酵母菌基因的转录本显示出排队核糖体的证据，这可能表明翻译延伸调控的存在。此外，与起始控制的信使RNA相比，这个转录本子集对不同的调控信号敏感，例如，在渗透压应激反应期间，这种独特的调控现象会发生。讨论：我们的分析为在常用模式生物中通过延伸阶段实施的翻译控制的普遍性提供了首次定量估计，并表明处于延伸调控下的转录本形成了一个可独立处理的RNA调控子集。