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Involvement of Noncanonical Short RNAs in gene repression through the RNA-induced-silencing complex

非规范短 RNA 通过 RNA 诱导沉默复合物参与基因抑制

基本信息

批准号：
10701797
负责人：
Anindya Dutta
金额：
$ 32.91万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-09 至 2026-06-30
项目状态：
未结题

项目摘要

ABSTRACT MicroRNAs have been studied for over two decades and found to impact extensively on various cellular functions like differentiation, proliferation and oncogenesis through regulation of gene expression using the Argonaute (Ago) containing RNA-induced silencing complex (RISC). In the cell, however, microRNAs co-exist with a nearly equal abundance of non-canonical short RNAs (ncsRNAs) that were not believed to enter the RISC. This has begun to change with our discovery that some members of the ncsRNAs, the tRNA derived fragments (tRFs) enter into RISC and silence gene expression, and others do not. The 18-26 base long tRF-3a molecules are derived from tRNAs by processes very different from the biogenesis of microRNAs, and yet repress gene expression by incorporation into Ago-RISC (RISC). In Aim 1 we will focus on specific tRF sub-classes, tRF-3b and tRF-1, that do not enter into Ago-RISC, to identify the surveillance pathways that keep short RNAs from dysregulating gene expression through RISC. We will study a methyltransferase that inactivates tRF-3b molecules by modifications on the RNA, a modification that is also regulated by demethylases that are inactivated by Isocitrate Dehydrogenase (IDH) mutations, seen in many cancers. We will also focus on an RNAse that degrades tRF-1 molecules to prevent them from entering into RISC and silencing gene expression. The results will reveal how the surveillance mechanisms work and how pathogenic or therapeutic alteration of the surveillance mechanisms will alter gene expression and improve RNA mediated therapy. In Aim 2 we will turn to ncsRNAs, exemplified by three tRF-3a molecules, that enter into RISC, silence gene expression and alter phenotypes of cancers and cancer cell-lines. We will test whether even in these cell line the tRF-3a molecules regulate gene expression by hijacking microRNA specific mechanisms and thus alter cellular phenotypes. We will also determine whether the ncsRNAs help or hinder microRNAs from doing their function. The field of short RNA mediated post-transcriptional gene regulation will be altered fundamentally by the recognition that microRNAs work in a complex milieu of other short RNAs that compete with or assist microRNAs, and that the cell has evolved mechanisms to protect the integrity of microRNA-mediated gene regulation.

抽象的 MicroRNA 已经被研究了二十多年，并被发现对多种疾病具有广泛的影响。通过基因调节实现分化、增殖和肿瘤发生等细胞功能使用含有 RNA 诱导沉默复合物 (RISC) 的 Argonaute (Ago) 进行表达。在然而，在细胞中，microRNA 与几乎相同丰度的非规范短 RNA 共存据信不会进入 RISC 的 RNA (ncsRNA)。随着我们的努力，这种情况已经开始改变发现 ncsRNA 的一些成员、tRNA 衍生片段 (tRF) 进入 RISC 和沉默基因表达，而其他则不然。 18-26个碱基长的tRF-3a分子是通过与 microRNA 的生物发生非常不同的过程从 tRNA 衍生而来的，但是通过纳入 Ago-RISC (RISC) 来抑制基因表达。在目标 1 中，我们将重点关注未进入 Ago-RISC 的特定 tRF 子类 tRF-3b 和 tRF-1，以识别通过 RISC 防止短 RNA 失调基因表达的监视途径。我们将研究一种甲基转移酶，它通过修饰 tRF-3b 分子来灭活 tRF-3b 分子。 RNA，一种也受异柠檬酸灭活的去甲基酶调节的修饰脱氢酶 (IDH) 突变，见于许多癌症。我们还将重点关注一种 RNAse 降解 tRF-1 分子，防止其进入 RISC 并沉默基因表达。结果将揭示监测机制如何运作以及致病性如何或监测机制的治疗改变将改变基因表达并改善 RNA介导的治疗。在目标 2 中，我们将转向 ncsRNA，以三个 tRF-3a 为例分子，进入RISC，沉默基因表达并改变癌症的表型癌细胞系。我们将测试即使在这些细胞系中，tRF-3a 分子是否也能调节通过劫持 microRNA 特定机制来改变细胞的基因表达表型。我们还将确定 ncsRNA 是否有助于或阻碍 microRNA 履行他们的职责。短RNA介导的转录后基因调控领域将是由于认识到 microRNA 在其他短链的复杂环境中工作，因此发生了根本性的改变。与 microRNA 竞争或协助的 RNA，并且细胞已经进化出机制保护 microRNA 介导的基因调控的完整性。