Studies of mRNA translational regulations in erythropoiesis

项目总结 本研究的目的是了解信使核糖核酸的翻译控制如何调节细胞的终末分化。 正常和病理条件下的红系细胞。红血球生成，红血球的产生， 对哺乳动物来说是必不可少的。这种细胞分化过程的故障会导致严重的贫血和IS 与大量的人类血液系统疾病有关，包括许多骨髓衰竭 像骨髓增生异常综合征这样的综合征。因此，表征控制的分子机制 红细胞生成具有生物学意义和临床意义。以前的研究已经描述了许多 控制红系细胞分化的转录调控网络。此外，转录本 已对红细胞生成过程中的动力学进行了广泛调查。这些RNA的变化是如何被“读”和 由翻译机构，核糖体，在分化的红系细胞中解释，以产生适当的 然而，蛋白质的数量在很大程度上仍然是未知的。最近，我们发现了广泛存在的关于 用平行RNA和核糖体图谱研究原发红系终末期红细胞的蛋白质合成 处于不同发育阶段的细胞。具体地说，在终末期红细胞生成过程中，我们发现了数百例 差异翻译的mRNAs及其3‘非翻译区的结合基序显著丰富。 几个红系特异的RNA结合蛋白，暗示翻译调控网络。此外，我们 发现了新形式的翻译规则，包括动态使用上游开放阅读框架， 多亚基复合体的化学计量合成，可选的翻译末端。这些结果 强烈主张动态翻译控制在红细胞生成中的关键作用。有趣的是，基因突变 细胞翻译装置的几个组成部分，核糖体，可以引起几种人类基因 表现为无效的红细胞生成的疾病，如钻石-布莱克凡贫血和5q- 综合症。这些临床观察突显了研究红系翻译调控的重要性。 细胞分化。在这项研究中，我们将：a)表征KEY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)确定疾病与 核糖体蛋白突变改变了红系细胞中的mRNA翻译。这项研究的结果不仅将填补 在红细胞生成方面的重要知识缺口，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.