中文摘要：

miR-148a是miR-148/152家族中的一员,对细胞增殖、细胞分化、癌症发生等生物过程有重要的调控作用.本研究采用Real-time quantitative PCR（qRT-PCR）方法,定量检测miR-148a在金华猪（Sus scrofa）不同发育时期肝脏中的表达变化,结果显示,miR-148a在胚胎期的肝脏中表达量最高;出生后,随着日龄的增加表达量逐渐降低;为了了解miR-148a的生物学功能和过程,对其进行GO （gene ontology）功能注释和KEGG （kyoto encyclopedia of genes and genomes）通路分析.结果显示,miR-148a参与肝脏的生长发育调控过程.为了验证miR-148a的靶基因,利用胎鼠（Mus musculus）肝细胞构建miR-148a过表达和抑制表达的细胞模型,以此来探究miR-148a的表达变化对靶基因在mRNA水平的影响.结果发现,在小鼠胎肝细胞中过表达miR-148a可以显著降低CCAAT增强子结合蛋白α基因（CCAAT-enhancer binding protein-alpha,Cebpa）的表达量（P＜0.05）.进一步检测发现,在金华猪肝脏生长过程中Cebpa与miR-148a的表达呈负相关.根据这些结果推测,miR-148a可能在肝脏发育过程中通过降低Cebpa的表达来调控细胞增殖和分化效应之间的平衡。

英文摘要：

miR-148a is a member of the miR-148/152 family, which participate in the regulation of many biological processes, such as cell proliferation and differentiation, cancer formation, and so on. In the present study, the expression of miR- 148a was detected in Jinhua pig （Sus scrofa） liver at various developmental stages by qRT-PCR. The result showed that its expression was abundant in embryonic period and became lower as the days increased after birth. To understand its biological functions and processes, GO （Gene ontology） annotation and KEGG （kyoto encyclopedia of genes and genomes） pathway analyses were subsequently performed on miR-148a. Bioinformatics comprehensive analysis indicated that miR-148a participated in the regulation of liver growth and development, especially in cell proliferation and differentiation. To confirm the putative miR-148a target genes, the expression changes of ten predicted genes were quantitatively analyzed at mRNA in over-expressed miR-148a mouse （Mus musculus） embryonic hepatocytes. The results revealed that over-expression of miR-148a could significantly reduced the mRNA expression of CCAAT-enhancer binding protein-alpha gene （Cebpa） （P〈0.05）. Moreover, the expression of miR- 148a and Cebpa also showed an inverse correlation in Jinhua pig liver at various developmental stages.These results suggested that miR-148a might reduce the expression of Cebpa to regulate the balance between cell proliferation and differentiation in liver development.