m6A mRNA modifications and myogenesis

项目摘要 N6-甲基腺苷（m6 A）是真核生物mRNA中最丰富的内部修饰， RNA。m6 A由Mettl 3复合物诱导，最常见于mRNA中的终止密码子和3'UTR附近。m6A 募集m6 A结合蛋白的YTH结构域家族，然后控制RNA的几乎每个方面 代谢，包括选择性剪接，核输出，稳定性和翻译。几千个mRNA 在给定的细胞群中，m6 A主要在DRACH的共有序列（D=A， G或U; R=A或G; H=A、C或U）。反映了m6 A的多种分子功能，它还调节广泛的 一系列生物现象，如癌细胞增殖、神经发育和多能干细胞 分化然而，m6 A在肌细胞分化中的作用在很大程度上仍然难以捉摸。PI的团队 最近发现肽基脯氨酰异构酶的Fkbp家族成员之一与Mettl 3复合物相互作用。 此外，Fkbp的缺失抑制了成肌细胞的分化，并降低了成肌细胞中m6 A的总水平。 细胞，这两种细胞都通过Mettl 3耗尽而重现。在分子水平上，Fkbp促进顺式-反式 Mettl 3及其相关蛋白Mettl 14的体外异构化。基于这些发现，他们假设， Fkbp通过Mettl 3和Mettl 14的异构化调节成肌细胞mRNA的m6 A水平。三个目标 被提出来调查这个假设。目的1将确定m6 A在成肌细胞中的全基因组分布 在单核苷酸水平上，研究Fkbp的耗尽如何改变模式。目标2将描述 m6 A如何影响几种最丰富修饰的成肌细胞特异性mRNA的代谢。目标3将研究 Fkbp 8如何调节Mettl 3和Mettl 14，重点是蛋白质的磷酸化和异构化。这些 这些研究有望为进一步研究m6 A在肌细胞中的作用奠定坚实的基础。

Project Summary N6-methyladenosine (m6A) is the most abundant internal modification of eukaryotic mRNA and long noncoding RNAs. m6A is induced by the Mettl3 complex most commonly near stop codons and 3’ UTRs in mRNAs. m6A recruits the YTH domain family of m6A-binding proteins, which then control almost every aspect of RNA metabolism, including alternative splicing, nuclear export, stability, and translation. Several thousand mRNA regions are modified by m6A in a given cell population, primarily at the consensus sequence of DRACH (D=A, G, or U; R=A or G; H=A, C, or U). Reflecting the diverse molecular functions of m6A, it also regulates a wide range of biological phenomena, such as cancer cell proliferation, neural development, and pluripotent stem cell differentiation. However, the roles of m6A in muscle cell differentiation remain largely elusive. The PI’s group recently found that one of the Fkbp family member of peptidyl prolyl isomerases interacts with the Mettl3 complex. In addition, depletion of the Fkbp inhibited myoblast differentiation and decreased the total level of m6A in the cells, both of which were recapitulated by Mettl3 depletion. At a molecular level, the Fkbp promotes cis-trans isomerization of Mettl3 and its related protein Mettl14 in vitro. Based on these findings, they hypothesized that the Fkbp regulates the m6A level of myoblast mRNAs through isomerization of Mettl3 and Mettl14. Three aims were proposed to investigate this hypothesis. Aim 1 will determine genome-wide distribution of m6A in myoblasts at a single nucleotide level and study how the pattern changes by depletion of the Fkbp. Aim 2 will characterize how m6A affects metabolism of several most abundantly modified myoblast-specific mRNAs. Aim 3 will study how Fkbp8 regulates Mettl3 and Mettl14, focusing on phosphorylation and isomerization of the proteins. These studies are expected to lay a solid foundation for a future study of the roles of m6A in muscle cells.