[细胞周期蛋白G1在小鼠卵巢中的表达及其与卵泡发育的关系]

Liu Zhao-Hua, Zhang Hui, He Ya-Ping, Zhang Jin-Hu, Yue Li-Min

Department of Physiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.

Sichuan Da Xue Xue Bao Yi Xue Ban. 2006 Nov;37(6):893-7.

OBJECTIVE

In this experiment, we investigated the expression of Cyclin G1 in mouse ovaries and explored the role of Cyclin G1 during ovarian folicular development and oocyte maturation.

METHODS

Immature female Kunming mice were treated with Pregnant Mare Serum Gonadotropin (PMSG) to induce the follicular development, with PMSG/human Chorionic Gonadotropin (hCG) to promote the ovulation and luteinization. The expression pattern of Cyclin G1 in ovary sections was determined by immunohistochemical analysis. The expression and localization of Cyclin G1 in isolated oocytes were evaluated by indirect immunofluorescence analyses.

RESULTS

The immunohistochemical staining showed that with the development of follicles, granulose cells showed to have the gradually increased Cyclin G1 levels and the expressing protein G1 localized clearly in cell nuclei. The Cyclin G1 was observed to express at all stage follicles of oocytes by immunohistochemical analysis. The localization of Cyclin G1 in oocytes was related to the developing stage of follicle. With the development of follicle, Cyclin G1 protein in the oocytes was transferred from the cell nucleus to the cytoplasm. Following anovulatory dose of hCG, the positive reactivity of Cyclin G1 in preovulatory granulosa cells was decreased. Furthermore, the luteinized granulosa cells showed the weak staining. And the expression of Cyclin G1 in atretic follicles was very low. Indirect immunofluorescence analyses demonstrated that Cyclin G1 was present in both GV (germinal vesicle) oocytes and those after GVBD (germinal vesicle breakdown), with increasing expression in oocytes after GVBD. Cyclin G1 was also present in both metaphase II (M II) eggs and fertilized eggs. Comparing with M II eggs, the positive immunostaining was increased in fertilized eggs.

CONCLUSION

The expression of Cyclin G1 in mouse ovary is in spatiotemporal pattern, which indicates that Cyclin G1 may play the role as a positive modulator of cell cycle in ovarian follicular development and oocyte maturation.

目的

在本实验中，我们研究了细胞周期蛋白G1（Cyclin G1）在小鼠卵巢中的表达，并探讨了Cyclin G1在卵巢卵泡发育和卵母细胞成熟过程中的作用。

方法

对未成熟雌性昆明小鼠注射孕马血清促性腺激素（PMSG）以诱导卵泡发育，注射PMSG/人绒毛膜促性腺激素（hCG）以促进排卵和黄体化。通过免疫组织化学分析确定卵巢切片中Cyclin G1的表达模式。通过间接免疫荧光分析评估分离的卵母细胞中Cyclin G1的表达和定位。

结果

免疫组织化学染色显示，随着卵泡的发育，颗粒细胞中Cyclin G1水平逐渐升高，且表达的蛋白G1清晰地定位于细胞核。通过免疫组织化学分析观察到Cyclin G1在卵母细胞的各个卵泡阶段均有表达。Cyclin G1在卵母细胞中的定位与卵泡的发育阶段有关。随着卵泡的发育，卵母细胞中的Cyclin G1蛋白从细胞核转移至细胞质。给予无排卵剂量的hCG后，排卵前颗粒细胞中Cyclin G1的阳性反应性降低。此外，黄体化颗粒细胞显示出弱阳性染色。而Cyclin G1在闭锁卵泡中的表达非常低。间接免疫荧光分析表明，Cyclin G1存在于生发泡（GV）期卵母细胞和生发泡破裂（GVBD）后的卵母细胞中，在GVBD后的卵母细胞中表达增加。Cyclin G1也存在于中期II（M II）期卵子和受精卵中。与M II期卵子相比，受精卵中的阳性免疫染色增加。