Understand the function of the MOS4-associated complex in microRNA biogenesis

项目摘要 多细胞生物编码小的非编码RNA，称为microRNA（miRNAs）， 通过对它们的靶mRNA施加抑制来表达。miRNAs合成缺陷和异常 miRNA活性与发育缺陷和疾病相关，包括人类。因此， 作为诊断和治疗目的的目标或用于诊断和治疗目的。然而，有几个关键的上限， 在miRNA的生物发生中。我们的长期目标是阐明如何精确控制miRNA水平。 miRNA来源于初级miRNA转录物（pri-miRNA），其含有一个或多个miRNA转录物， 不完美的茎-环，其中存在miRNA。Pri-miRNA是共转录加工的。但据 目前尚不清楚加工复合物是如何形成和募集到pri-miRNAs的。此外，大多数pri-miRNAs 因此，非编码RNA可能是核RNA质量控制机制（QC）的目标。的确， 不能保护pri-miRNA免于降解导致发育缺陷。然而，保护过程 未定义降解产生的pri-miRNA。 来自植物的MOS 4-assoicated complex（MAC）是一种保守的复合物， 附件组件。MAC在后生动物和真菌中的直向同源复合物被称为PRP 19 复体和十九复体。它们与剪接体相关， 剪接、DNA损伤修复和基因组稳定性。我们以前的研究使我们提出，MAC链路pri- miRNA的转录、加工和稳定性。我们假设MAC对于共同- pri-miRNAs的转录加工和稳定性。我们的具体目标将测试以下假设：1） MAC作为一个整体复合物来调节miRNA的生物合成; 2）MAC结合pri-miRNAs来保护它们 3）磷酸化依赖性的泛素连接酶活性对于miRNA的表达至关重要。 生物起源 总的来说，我们的研究将通过描述MAC在 pri-miRNAs的转录，加工复合物的形成，pri-miRNAs的稳定化和 处理复杂的活动。因此，我们的研究将提高我们理解miRNA的能力- 介导的基因调控，并开发可用于改善人类健康的miRNA相关技术。 作物健康和农业性状

Project Summary Multicellular organisms encode small non-coding RNAs called microRNAs (miRNAs) to regulate gene expression by exerting repression on their target mRNAs. Defective synthesis of miRNAs and abnormal miRNA activity are associated with developmental defects and diseases, including human. Thus, miRNAs are being targeted or used for both diagnostic and therapeutic purposes. However, there are several critical caps in miRNA biogenesis. Our long-term goal is to elucidate how miRNA levels are precisely controlled. miRNAs are derived from the primary miRNA transcripts (pri-miRNAs), which contain one or more imperfect stem-loop (s) where miRNAs reside. Pri-miRNAs are co-transcriptionally processed. However, it is not clear how the processing complex is formed and recruited to pri-miRNAs. Moreover, most pri-miRNAs are non-coding RNAs, and therefore, are likely targets of the nuclear RNA quality control machinery (QC). Indeed, failure to protect pri-miRNA from degradation causes development defects. However, the process protecting pri-miRNA from degradation is not defined. The MOS4-assoicated complex (MAC) from plants is a conserved complex composed of core and accessory components. The ortholog complexes of MAC in metazoan and fungi are known as the PRP19 complex and the nineteen complex, respectively. They associate with spliceosome and are required for splicing, DNA damage repair and genome stability. Our previous study leads us to propose that MAC links pri- miRNA transcription, processing and stability together. We hypothesize is that MAC is important for co- transcriptional processing and stability of pri-miRNAs. Our specific aims will test the following hypotheses: 1) MAC functions as a whole complex to modulate miRNA biogenesis; 2) MAC binds pri-miRNAs to protect them from XRN2/3 activity; 3) Phosphorylation-dependent ubiquitin ligase activity of MAC3 is critical for miRNA biogenesis. Collectively, our research will produce a broad impact by characterizing the roles of MAC in the transcription of pri-miRNAs, formation of processing complex, stabilization of pri-miRNAs and regulation of the activity of processing complex. Consequently, our research will improve our ability to understand the miRNA- mediated gene regulation and to develop miRNA-related technologies that can be used to improve human health and agricultural trait of crops