中文摘要：

在卵母细胞成熟过程中,细胞周期蛋白A2（Cyclin A2,Cyc A2）可与不同周期蛋白依赖激酶（cyclindependent kinase,CDK）相互作用,通过其周期性表达和降解,参与调控细胞周期。为探讨Cyc A2基因对猪（Sus scrofa）卵母细胞体外成熟的影响,本研究从猪卵巢中克隆Cyc A2基因,构建野生型p Venus-Cyc A2和非降解型p Venus-DN157Cyc A2真核表达载体,转染至hela细胞,确认重组质粒的表达及定位情况。将p Venus-Cyc A2、p Venus-DN157Cyc A2体外转录为c RNA,对猪卵母细胞进行显微注射后,体外成熟培养一段时间后统计第一极体排出率,并观察其表达和定位。结果显示,显微注射了p Venus-Cyc A2、p Venus DN157Cyc A2c RNA的卵母细胞,其第一极体（first polar body,PB1）的排出率与对照组相比极其显著降低（P〈0.001,）;用Roscovitine处理的p Venus-DN157Cyc A2表达的卵可恢复排出PB1的能力,其PB1排出率与对照组相比差异不显著。本研究首次揭示了Cyc A2基因对猪卵母细胞体外成熟过程的影响,为探索Cyc A2参与染色体分离调控的分子机制提供理论依据,同时也为进一步研究第二次减数分裂过程中Cyc A2基因的作用提供了一个平台。

英文摘要：

During the process of oocyte maturation, CyclinA2（CycA2） controls the progression of cell cycle by activating different cyclin-dependent kinase （Cdk）, which regulates the cell cycle through its expression and degradation. Eukaryotes contain 2 distinct types of CycA2 of A1 and A2. The transcription of CycA2 initiates in late G1, peaks and plateaus in mid-S, declines in G2 and totally disappears in metaphase. CycA2 is also involved in the G1/S and G2/M transitions. CycA2 is degradated by ubiquitin-proteasome system in mitosis. In recent study, it is reported that CycA2 also plays an important role in the meiotic division of female germ cells. It can promote entry into the first meiosis in mouse （Mus musculus） oocyte, furthermore, there is an unexpected role for its requirement for the sister chromatid segregation in the second meiosis. These results all suggest that CycA2 has an important role in oocyte maturation and embryo development. In order to investigate the effect of CycA2 on porcine （Sus scrofa） oocytes during in vitro maturation （IVM） in the present study, firstly, CyeA2 gene was cloned from pig ovary by RT-PCR and constructed 2 eukaryotic vectors, the wild type pVenus-CycA2 and non-degradated pVenus-DN157CycA2, which were transfected into hela cells to confirm their expression and location by fluorescence microscopy observation and qRT-PCR. The cRNA of pVenus- CycA2 and pVenus-DN157CycA2 transcripted in vitro were microinjeted into porcine oocytes. Finally, the oocytes microinjected pVenus-CycA2 and pVenus-DN157CycA2 cRNA were collected for mature cultivation and the rate of the first polar body （PB1） extrusion were calculated. Besides, the CDK1 inhibitor roscovitine were used to treat the oocytes which were microinjected the DN157roscovitine cRNA and the rate of the PB 1 extrusion was also examined. The results showed that the recombinant vector pVenus-CycA2 and pVenus- DN157CycA2 were successfully constructed. After transfection or microinjection, the fusion protein could expres