基于逆向挖掘技术获取水稻和拟南芥新的miRNAs-靶基因调控网络

MicroRNAs (miRNAs) play an important role in the regulation of eukaryotic gene expression. More and more novel miRNA genes are being cloned in recent years. Identification of the target genes of the miRNAs is a hot topic of the miRNA research area, which is required to elucidate the undetermined functions of the already registered miRNAs in miRBase. The newly developed high-throughput sequencing (HTS) technology provides a powerful tool for the identification of new miRNAs and their targets. In plants, by using degradome sequencing data, the miRNA-guided target cleavages could be reliably identified. In this proposed research project, we will establish a novel framework for the extraction of new miRNA-target regulatory relationships through a backward approach. Using this strategy, a large-scale data mining will be carried out based on the publicly available HTS data. The study includes: 1. identification of new miRNA genes; 2. identification of the downstream targets of the miRBase-registered miRNAs with undetermined functions; 3. construction of miRNA-mediated gene regulatory networks. Moreover, we will investigate the alternative splicing of miRNA/miRNA* duplexes on certain pre-miRNAs (precursor microRNAs). Based on these studies, we hope to expand the current understanding of the biological roles of the miRNA genes in plants.

microRNA（miRNA）在真核生物基因表达调控中起着重要作用。近年来，新的miRNA基因不断被发现。下游靶基因鉴定是miRNA生物学功能研究的重点；在目前已报道的miRNA中，仍有一大部分功能不详。高通量测序技术为miRNA及其靶基因的鉴定提供了帮助, 基于降解组测序数据获得的miRNA介导的靶mRNA切割位点信息，我们将建立一种逆向挖掘植物中miRNA-target互作的全新技术流程。运用该策略，将对拟南芥、水稻海量高通量测序数据进行大规模分析：1. 期望发现一批新的miRNA基因,2. 揭示miRBase中功能不详的miRNA与潜在靶基因间的调控关系,3构建特定miRNA参与的基因表达调控网络。此外，我们还将研究miRNA/miRNA*短双链结构在同一个miRNA前体上的可变剪切形式及其生物学意义。以上研究将拓展人们对miRNA在植物中的调控功能的认识。

microRNA在真核生物基因表达调控中起着重要作用。 miRNA新基因的挖掘及其功能研究是目前miRNA研究的前沿热点。在国家自然科学基金的支持下,我们围绕“水稻和拟南芥新的 microRNA-靶基因调控网络”开展了如下工作:（1）建立了一种全新的 microRNA挖掘算法；（2）在水稻和拟南芥中找到了一批新的 microRNA及其靶基因；（3）发现了一批水稻发育时期特异积累的sRNA，并构建了其介导的基因调控网络；（4）发现了miRNA新的调控机制； （5）修正了microRNA激发的ta-siRNA合成模型，并找到了一批ta-siRNA新基因及其靶基因。以上研究拓展人们对 microRNA 在植物中的调控功能的认识。