中文摘要：

【目的】MicroRNAs（miRNAs）是一类长度约22 nt的非编码RNA,通过转录后调控的方式在多种生命活动中发挥重要功能。Argonaute1（AGO1）蛋白作为miRNA沉默复合物（miRNA silencing complex RISC）的重要组成部分,在miRNA调控通路中起着关键作用。论文旨在研究AGO1的生物学功能及其对飞蝗（Locusta moratoria）生长发育的影响,为探索昆虫miRNA的生物合成和农业害虫的有效控制提供理论依据。【方法】采用生物信息学方法在飞蝗转录组数据库中获得Lm AGO1 c DNA序列;使用在线蛋白翻译软件（Ex PASy）对Lm AGO1进行蛋白翻译,利用SMART分析Lm AGO1蛋白的功能结构域;选取家蚕（Bombyx mori）、果蝇（Drosophila melanogaster）和赤拟谷盗（Tribolium castaneum）等模式昆虫的同源序列与Lm AGO1氨基酸序列进行聚类分析,采用Phyml软件构建昆虫AGO蛋白的系统发育树;为了进一步研究Lm AGO1在飞蝗生长发育过程中的作用,使用T7 RiboMAX~（TM） Express RNAi System体外合成Lm AGO1的ds RNA,在飞蝗4龄第2天和5龄第2天若虫期连续两次注射ds RNA进行干扰,同时注射ds GFP作为对照。分别收集注射ds RNA后48 h和72 h的整虫样品提取RNA,反转录为c DNA。通过实时荧光定量PCR（RT-q PCR）检测Lm AGO1在不同时间点的干扰效率并观察虫体的发育表型。同时,为了检测Lm AGO1沉默是否会影响miRNA的生物合成,采用RT-q PCR对飞蝗体内5个高丰度miRNA表达进行定量分析。【结果】Lm AGO1蛋白含845个氨基酸,具有典型的AGO蛋白家族保守结构域,即位于213—348位点的PAZ结构域和502—804位点的PIWI结构域。聚类分析表明,Lm AGO1蛋白与其他昆虫的AGO1蛋白聚为一类。通过AGO1氨基酸序列同源比对结果显示Lm AGO1与模式昆虫果蝇、家蚕AGO1的氨基酸序列一致度高达82.2%和86.9%。RNAi结果表明,虫体注射ds Lm AGO1 48 h和72 h后,与对照组相比,Lm AGO1表达量均显著降低,干扰效率分别为88

英文摘要：

[Objective] MicroRNAs （miRNAs） are small （approximately 22 nt）, noncoding RNA molecules that play important roles through post-transcriptional regulation in a wide range of biological process. As an essential component of miRNA silencing complex （RISC）, Argonautel （AGO1） protein plays a key role in miRNA regulatory pathway. The purpose of this study is to explore the biological function of LmAG01, and determine its impacts on growth and development in the migratory locust. These results will provide an important theoretical basis for biogenesis mechanism of insect miRNAs and effective pest control. [ Method] The cDNA sequence of LmAGO1 was identified from the locust transcriptome database by using bioinformatics approaches, and was translated into protein sequence using online protein translation software （ExPASy）. The conserved domains were analyzed by SMART based on the deduced protein sequence. A phylogenetic tree of insect AGO was constructed with the locust AGO1, the homologous amino acid sequences from Bombyx mori, Drosophila melanogaster, Tribolium castaneum and other insects using the Phyml program. The double-strand RNAs （dsRNAs） of AGO1 gene were synthesized in vitro using T7 RiboMAX^TM Express RNAi System. The RNA interference （RNAi） experiment was preformed to explore the biological function of LmAGO1 during growth and development in locusts. The dsLmAGO1 was injected into the locust nymphs on day 2 of the 4th-instar and 5th-instar stages, respectively. The injection of dsGFP was used as the control. At the 48 h and 72 h after dsRNA injection, the whole body of locust nymphs was collected for total RNA isolation and cDNA synthesis. The reverse transcript quantitative PCR （RT-qPCR） analyses of the LmAGO1 were performed to determine the gene silencing efficiency. In order to evaluate the influences of the LmAGO1 RNAi on miRNA biogenesis, the five abundantly expressed miRNAs were selected to quantify their expression level by using RT-qPCR after dsLmAGO1 injection. [ Resul