Argonaute（AGO）蛋白是小RNA介导的基因沉默途径的核心效应分子。多细胞生物通常有多个AGO蛋白。在果蝇、线虫等低等生物中，多个AGO已演变出专门的职能参与不同的RNA沉默途径。相比之下，关于哺乳动物不同AGO蛋白在细胞中如何分工及其机制如何仍有待阐明。我们前期研究发现：在胚胎发育的小鼠肝脏中，四个AGO（AGO1-4）的表达模式有很大差异，为我们解析体内AGO之间的分工提供了良好的研究模型。在此基础上，本项目拟采用HITS-CLIP技术 (紫外交联免疫沉淀获得RNA进行高通量测序)，结合生物信息分析，在转录组水平系统研究小鼠胚肝细胞中不同AGO蛋白在小RNA分拣和靶标选择上的异同，解析肝脏发育过程中不同AGO蛋白-小RNA-靶标组成的基因调控网络的动态变化，阐明四种AGO蛋白的特异性职能及其独特的表达模式对于肝脏发育的重要意义。

Argonaute (AGO) proteins are the core effectors of small RNA-mediated gene silencing pathways. Multicellular organisms usually have multiple AGO family proteins. In lower organisms such as Caenorhabditis elegans and Drosophila melanogaster, multiple AGOs have evolved specialized functions for distinct RNA silencing pathways. By contrast, in mammalian cells the functional division of different AGO proteins as well as the mechanisms remain to be elucidated. In the previous study we found that the expression patterns of four AGO proteins (AGO1-4) are significantly different in the livers of developing mouse embryos, providing an excellent model for the research on the functional division of mammalian AGO proteins in vivo. On this basis, we will utilize the HITS-CLIP approach (high-throughput sequencing of RNAs isolated by crosslinking immunoprecipitation) combined with bioinformatic analysis to systematically identify and compare the AGOs-associated small RNAs and their targets in mouse embryonic liver cells at transcriptome-wide level, demonstrate the dynamic changes of the gene regulatory networks composed by individual AGOs-small RNAs-target RNAs during liver development. Altogether, this study will clarify the specialized role of each AGO protein and shed light on the biological significance of the unique expression patterns of AGO proteins during liver development.