中文摘要：

microRNA-200b（miR-200b）具有类似的调控哺乳动物体型大小的功能，但尚未在哺乳动物个体上进行验证。为研究microRNA-200b在小鼠发育过程中的表达，探讨microRNA-200b及其靶标基因在小鼠体型发育调控中的关键作用，本研究从小鼠（Musmusculus）基因组中扩增得到miR-200b前体序列，并验证了该miRNA的茎环前体结构；采用生物信息学软件预测miR-200b可能的靶基因，并通过双荧光素酶报告载体系统验证了miR-200b与靶基因3＇UTR的相互作用；通过荧光定量PCR技术分别分析了miR-200b在成年小鼠体内各组织中和miR-200b及其靶标基因在小鼠胚胎发育不同时期的表达变化。结果显示，克隆到的鼠miR-200b前体序列能够形成茎环结构；软件预测和细胞实验证实Fog2基因是miR-200b的靶标基因，且二者在小鼠胚胎发育第10．5天到第15天时表达呈负相关趋势；qRT—PCR结果表明，miR-200b在成年雌性小鼠各组织中均有表达，在肌肉、肾脏和子宫中表达量高，在心脏、脾脏和肺脏中表达量偏低。根据表达谱和靶标验证结果推测，miR-200b通过与靶基因Fog2的互作参与小鼠胚胎发育过程。

英文摘要：

microRNA-200b （miR-200b） has similar functions in regulating body size in mammals, while its exact roles has not been examined in mammals. To study the expression of miR-200b during the embryo development stage, and investigate the important roles of miR-200b and its target gene in regulating the body size of mouse, in this study, precursor miR-200b was amplified from the mouse （Mus musculus） genome DNA, RNA folding sofware was used to construct the secondary structure of miR-200b; potential target genes were predicted with bioinformatic software, and validated through Dual-luciferase reporter assay system; the expression profiles ofmiR-200b and its target gene Fog2 were detected using Real-time PCR in different tissues of adult mouse and embryos at the stage of 10.5-15.0 days after coitus. The results showed that the miR-200b precursor had the typical stem-loop structure of microRNA, and the Fog2 gene was predicted and tested to be a target gene of miR-200b, which showed negatively related expression to miR-200b in the embryos dpcl0. 5-15.0; qRT-PCR results showed that the miR-200b was expressed in almost all the tissues of female mouse, with higher expression in muscle, kidney and uterine, and lower expression in heart, spleen and lung tissues. From the expression profile and target gene testing results, we can conclude that miR-200b may play important roles in regulating mouse embryo development through acting with its target gene Fog2.