核糖体蛋白表达缺失相关的核糖体组分异质性及翻译调控选择性研究

Ribosome is a kind of important cellular organelles, responsible for mRNA translation. While ribosomes have been traditionally taken as homogenous ribonucleoprotein complexes, recent studies revealed that ribosomal compositional heterogeneity could cause ribosome diversity, of which species and stoichiometry of ribosomal proteins (RP) are distinctive. Certain RP enriched ribosomes could selectively translate mRNA molecules; and genetic mutations or changed expression of different RPs have been related to different and specific phenotypes and human diseases. In our pilot study, RP expression changes were significantly related to specific transcriptional and translational changes. Nevertheless, till now, little is known about RP related translational specificity and their specificity in translational regulation or coordination. This project plans to parse this kind of specificity by combining transcriptome and translatome of cell lines treated using gene knockdown technology. We will deeply analyze RP related translational regulation events, and further study representative RP contribution to ribosome biogenesis and assembly as a paradigm. Our results will advance our knowledge about RP functionality and their specificity in translational regulation, widen the scope of gene expression network, and hence provide valuable hints on looking for pathological mechanisms or potential drug targets for human disease and cancer.

核糖体是一类重要的细胞器，负责mRNA翻译。传统认为核糖体是同质的核糖核蛋白复合物；新研究发现，核糖体组分异质性会导致核糖体多样性，不同核糖体中核糖体蛋白(Ribosomal protein，RP)的种类和化学计量关系不同。富含某RP的核糖体对mRNA的翻译具有选择性；不同RP的遗传突变和表达水平的变化还与特异的表型谱和疾病谱相关。我们的预实验表明， RP 的低表达与特异的转录组和翻译组变化相关。迄今，我们对于RP参与的翻译及其调控特异性和协同性知之甚少。本项目拟基于基因敲减技术，结合转录组和翻译组，解析RP 参与翻译调控的特异性，深入挖掘RP相关的翻译调控事件，进一步探讨个别RP对核糖体生成和正常组装的作用机制范例。我们的研究结果将促进对 RP 功能和翻译调控过程的深入了解，扩充基因表达调控网络，对RP相关人类复杂疾病和癌症的机理解析及药物靶点发掘具有一定的科学意义和潜在的临床应用价值。

核糖体是一类重要的细胞器，负责mRNA翻译。传统认为核糖体是同质的核糖核蛋白复合物；新研究发现，核糖体蛋白(Ribosomal protein，RP)的种类和化学计量关系在不同核糖体中不同，导致核糖体组分异质性。富集特定RP的核糖体对mRNA的翻译具有选择性；不同RP的遗传突变和表达水平的变化与特异的表型谱和疾病谱相关。总地来说，我们对于RP参与的基因表达及其调控特异性和协同性知之甚少。本研究通过Ribo-seq和RNA-seq系统分析了75个RP蛋白(44个来自大亚基60S和31个来自小亚基40S)敲除后的翻译和转录变化。单个RPs的缺乏在转录和翻译上改变了特定的基因子集。RP基因在核糖体应激下处于共翻译调控状态，60S RPs和40S RPs表达下调对基因转录和翻译具有相反的作用。RP缺乏改变了与八种主要功能类别相关的基因表达，包括细胞周期、细胞代谢、信号转导和发育。与40S RP缺乏相比，60S RP缺乏通过P53信号通路对细胞生长产生更大的抑制作用。特别地，该研究发现eS8/RPS8缺乏会刺激细胞凋亡，而eL13/RPL13或eL18/RPL18缺乏会促进细胞衰老。该研究还分别验证了uL5/RPL11和eL15/RPL15缺乏对视网膜发育和血管生成的表型影响。总体而言，该研究为核糖体在细胞表型、发育和疾病中的调控研究提供了宝贵的资源和新的见解。