Biogenesis of mRNA-derived telomerase long noncoding RNA

项目摘要 在哺乳动物细胞中转录的大多数RNA分子不编码蛋白质序列。其中 非编码RNA（ncRNA）是大于200 nt的长非编码RNA（lncRNA）的大家族。 LncRNA可以通过影响许多基因的转录来调节细胞蛋白质表达模式， mRNA和ncRNA的转录后命运，以及蛋白质的周转和定位。端粒酶 RNA是一类独特的lncRNA，作为端粒酶核糖核蛋白的组成部分发挥作用 在癌症和干细胞中维持基因组稳定性和细胞永生的复合物。总体 本项目的目的是了解一种新的mRNA衍生的生物合成的机制和调控， 玉米黑粉菌（Ustilago maydis）端粒酶RNA（lncRNA）研究 在子囊菌酵母和动物中，端粒酶RNA由RNA转录， 聚合酶II，并与小核RNA（snRNA）和盒H/ACA小共享生物发生途径 核仁RNA（snoRNA）。相反，纤毛虫和植物中的端粒酶RNA是由 RNA聚合酶III。这些同源端粒酶RNA所采用的不同的生物发生机制 来自不同真核生物界或群体的分子为理解 大量非编码RNA的生物发生和进化的基本原理 生物学中的物种 我们最近首次从U.玉米，一种真菌模型 有机体动物和酵母TR由RNA聚合酶II转录，在5 '端具有保护帽。 有趣的是，maydis TR缺乏保护性的5'帽，并且是从一个非编码区的3'非翻译区加工而来的。 蛋白质编码mRNA前体。在这项研究计划中，我们将确定TR前体中的决定因素， 调节成熟的美国大豆的生物发生。从编码蛋白质的mRNA中提取玉米TR。我们亦会研究 mRNA前体中编码的蛋白质的功能和表达。最后，我们将鉴定端粒酶 辅助蛋白在U.玉米，并确定他们的作用，在调节美国。玉米TR生物发生 这些具体目标的成功结果将提供全面和令人兴奋的细节， 了解端粒酶lncRNA前所未有的mRNA衍生的生物合成机制。

Project Summary Most RNA molecules transcribed in mammalian cells do not encode for protein sequences. Among these noncoding RNAs (ncRNA) is a vast family of long noncoding RNAs (lncRNAs) that are larger than 200 nt. LncRNAs can modulate cellular protein expression patterns by influencing the transcription of many genes, the post-transcriptional fate of mRNAs and ncRNAs, and the turnover and localization of proteins. Telomerase RNA is a unique class of lncRNA that functions as an integral component of the telomerase ribonucleoprotein complex which maintains genomic stability and cellular immortality in cancer and stem cells. The overarching goal of this project is to understand the mechanism and regulation of a novel mRNA-derived biogenesis of telomerase RNA (lncRNA) in Ustilago maydis, a basidiomycete fungus. Telomerase RNA in Ascomycete yeasts and animals, telomerase RNAs are transcribed by RNA polymerase II and share biogenesis pathways with small nuclear RNA (snRNA) and box H/ACA small nucleolar RNA (snoRNA), respectively. In contrast, telomerase RNAs in ciliates and plants are transcribed by RNA polymerase III. These distinct biogenesis mechanisms employed by these homologous telomerase RNA molecules from different eukaryotic kingdoms or groups provide unparalleled opportunities for understanding the fundamental principles underlying the biogenesis and evolution of the vast varieties of noncoding RNA species in biology. We have recently identified the first Basidiomycete telomerase RNA from U. maydis, a fungal model organism. Animal and yeast TRs are transcribed by RNA polymerase II with a protective cap at the 5’-end. intriguingly, the U. maydis TR lacks a protective 5’ cap and is processed from the 3’-untranslated region of a protein-coding mRNA precursor. In this research program, we will identify determinants in the TR precursor that regulate the biogenesis of the mature U. maydis TR from the protein-coding mRNA. We will also study the function and expression of the protein encoded in the mRNA precursor. Lastly, we will identify telomerase accessory proteins in U. maydis and determine their roles in regulating the U. maydis TR biogenesis. Successful outcomes of these specific aims will provide comprehensive and exciting details needed for understanding the unprecedented mRNA-derived biogenesis mechanism of telomerase lncRNA.