The role of small RNA derived tRNAs in gene regulation: Mechanism and Therapeutic Applications

摘要 现代遗传学中最重要的概念之一是认识到超过90%的哺乳动物 基因组被转录成RNA。这些非蛋白质编码RNA被称为暗物质 作为大多数这些RNA的功能，基因组的功能还有待确定。五年前，我们 偶然发现了一组新的tRNA衍生的小RNA（tsRNA）。这些tRNA衍生片段也是 通常称为trfRNA，最初被认为是降解产物。但现在 很明显，在哺乳动物细胞中产生了成百上千种不同的RNA片段， 越来越多的证据表明这些功能很重要。作为一个群体， 在许多不同的水平上调节基因。我们计划研究3 'tsRNA（来自于DNA的3'末端）， 成熟的tRNA）目前是各种类型的片段中研究得最少的，并且没有确定的 功能还有待描述。我们已经确定了一种特异性RNA，22 nt CAG-亮氨酸， 当在快速分裂的细胞中通过加入反义寡核苷酸下调3 'tsRNA时， 通过首先限制至少一种核糖体蛋白质mRNA的翻译来控制核糖体生物发生。这导致 快速细胞凋亡。相比之下，添加3 '-tsRNA模拟物增加细胞增殖，并可 补充细胞中的核糖体生物合成缺陷。这些数据揭示了一个以前未知的职位- 转录基因调控途径。我们计划进一步探讨这种具体的机制， 3 'tsRNA介导的翻译基因调控以及使用新的高通量测序方法 鉴定并测试其他可能参与类似基因调控的3 'tsRNA。最后我们 建议使用基因治疗和寡核苷酸反义递送来追求 在治疗影响肝脏的医学病症中操纵3 'tsRNA。我们相信解开 这种调控回路的分子机制对于进一步了解基因是如何 调节并将提供新的治疗靶点。

ABSTRACT One of the most important concepts in modern genetics is the realization that over 90% of the mammalian genome is transcribed into RNA. These non-protein coding RNAs have been described as the dark matter of the genome as the function of most of these RNAs has yet to be determined. Just over 5 years ago, we stumbled onto a novel set of tRNA derived small RNAs (tsRNAs). These tRNA derived fragments are also commonly called trfRNAs, and were originally thought to represent degradation products. However, it is now clear there are hundreds or perhaps thousands of different RNA fragments generated in mammalian cells and there is increasing evidence that these are functionally important. As a group, they have been proposed to regulate genes at many different levels. We plan to study the 3’tsRNAs (derived from the 3’ end of the mature tRNA) currently the least well studied of the various types of fragments, and for which no definitive function has yet to be described. We have established that one specific RNA, the 22nt CAG-Leucine 3’tsRNA when down regulated by the addition of antisense oligonucleotides in rapidly dividing cells inhibits ribosome biogenesis by first limiting the translation of at least one ribosomal protein mRNA. This results in rapid cellular apoptosis. In contrast, the addition of a 3’tsRNA mimic increases cellular proliferation and can complement the ribosome biogenesis defects in cells. These data bring to light a previously unknown post- transcriptional gene regulatory pathway. We plan to further explore the mechanism of how this specific 3’tsRNA-mediates translational gene regulation as well as use new high-throughput sequencing approaches to identify and then test other 3’tsRNAs that may participate in similar types of gene regulation. Finally, we propose to use gene therapy and oligonucleotide antisense delivery to pursue the therapeutic potential of manipulating 3’tsRNAs in treating medical conditions that affect the liver. We believe unraveling the molecular mechanism of this regulatory circuit is important both to further understand how genes are regulated and will provide novel therapeutic targets.