中文摘要：

microRNA（miRNA）是一类长度为22nt左右的单链非编码小RNA分子，通过与靶mRNA分子结合而沉默其表达．目前，虽然在多种生物中发现了大量的miRNA，但对它们的功能还知之甚少．为了深入研究miRNA的功能，构建了一个包括170多种人源miRNA表达载体的miRNA分子表达库，并对部分表达载体采用RNA印迹及双荧光素酶分析技术进行验证．实验证明：这些miRNA表达载体在HEK-293细胞内可以高水平表达miRNA前体和成熟的miRNA，并且能抑制含有相应靶位点的报告基因的表达．这些结果表明：该miRNA表达库可以表达功能miRNA，并可用于miRNA功能的筛选和研究．

英文摘要：

The microRNAs （miRNAs） are a kind of single strand small noncoding RNAs （approximately 22nt） with probable roles in the silencing gene expressions. To date, a large number of miRNAs have been identified in several organisms, but the function of the vast majority of these molecules remains to be determined. To study their functions, a library of vectors expressing miRNAs, including more than 170 kinds of human miRNAs were developed. The ability of some miRNA vectors to express miRNAs was validated with Northern blot and dual luciferase assays. The results indicated that these vectors could express pre-miRNAs and mature miRNAs in HEK-293 cells. Furthermore, they could suppress the expression of luciferase tagged with a sequence complementary to corresponding miRNAs. All these data show that these miRNA expression vectors can drive functional miRNA expression, and they can be used to screen functional miRNAs.