Studies of mRNA translational regulations in erythropoiesis

项目摘要 本研究的目的是了解mRNA的翻译调控是如何调节终末分化的。 在正常和病理条件下的红系细胞。红细胞生成，红细胞的产生， 是哺乳动物的必需品这种细胞分化过程的功能障碍可导致严重的贫血， 与大量人类血液系统疾病相关，包括许多骨髓衰竭 综合征，如骨髓增生异常综合征。因此，表征控制 红细胞生成具有生物学和临床意义。以前的研究已经描述了许多 控制红系细胞分化的转录调节网络。此外，转录组学 红细胞生成过程中的动力学已被广泛研究。这些RNA变化是如何被“读取”的， 在分化的红细胞中，由翻译装置核糖体解释，以产生适当的 然而，蛋白质的量在很大程度上仍然是未知的。最近，我们发现了广泛的法规， 初级红系细胞蛋白质合成的RNA和核糖体平行分析 不同发育阶段的细胞。具体来说，在终末红细胞生成过程中，我们发现了数百个 差异翻译的mRNA，其3'非翻译区具有显著富集的结合基序， 几个红细胞特异性RNA结合蛋白，这意味着翻译调控网络。而且我们 发现了新形式的翻译调节，包括上游开放阅读框架的动态使用， 替代翻译终止和多亚基复合物的化学计量合成。这些结果 有力地论证了动态翻译控制在红细胞生成中的关键作用。有趣的是， 细胞翻译装置的几种成分，核糖体，可以引起几种人类遗传学上的疾病。 具有无效红细胞生成表现的疾病，如Diamond-Blackfan贫血和5 q- 综合征这些临床观察突出了研究红系细胞翻译调控的重要性。 细胞分化在这项研究中，我们将：a）表征关键介导的翻译调控网络， 正常红细胞生成中的红系特异性RNA结合蛋白; B）确定疾病相关性RNA结合蛋白如何与红系特异性RNA结合蛋白结合。 核糖体蛋白突变改变红系细胞中的mRNA翻译。这项研究的结果不仅将填补 这是红细胞生成方面的一个重要知识缺口，但也将提供重要的分子见解， 核糖体病，并有可能确定这些人类疾病的治疗靶点。

PROJECT SUMMARY The goal of this study is to understand how mRNA translational control regulates the terminal differentiation of erythroid cells under both normal and pathological conditions. Erythropoiesis, the production of red blood cells, is essential to mammals. Malfunction of this cell differentiation process can cause severe anemias and is associated with a large number of human hematological disorders, including many bone marrow failure syndromes such as the myelodysplastic syndrome. Thus, characterizing the molecular mechanisms controlling erythropoiesis is of both biological and clinical significance. Previous studies have characterized many transcriptional regulatory networks controlling the erythroid cell differentiation. In addition, the transcriptomic dynamics during erythropoiesis have been extensively surveyed. How these RNA changes are “read” and interpreted by the translational apparatus, the ribosome, in the differentiating erythroid cells to generate proper amounts of proteins, however, is still largely unknown. Recently, we uncovered widespread regulations of protein synthesis during terminal erythropoiesis by parallel RNA and ribosome profiling on primary erythroid cells at different developmental stages. Specifically, during terminal erythropoiesis, we identified hundreds of differentially translated mRNAs, and their 3' untranslated regions have significantly enriched binding motifs of several erythroid-specific RNA-binding proteins, implying translational regulatory networks. Moreover, we found novel forms of translational regulations including dynamic usage of upstream open reading frames, alternative translation terminations, and stoichiometric synthesis of multi-subunit complexes. These results strongly argue for critical roles of dynamic translational control in erythropoiesis. Interestingly, mutations in several components of the cellular translational apparatus, the ribosome, can cause several human genetic diseases with manifestations of ineffective erythropoiesis, such as the Diamond-Blackfan anemia and the 5q- syndrome. These clinical observations highlight the importance of studying translational regulations in erythroid cell differentiation. In this study, we will: a) characterize the translational regulatory networks mediated by key erythroid-specific RNA-binding proteins in normal erythropoiesis; b) determine how disease-associated ribosomal protein mutations alter mRNA translation in erythroid cells. The results from this study will not only fill an important knowledge gap in erythropoiesis, but also will provide important molecular insights into ribosomopathies and potentially identify therapeutic targets for these human diseases.