【摘要】 本研究探讨了原癌基因c-erbB2和c-myb对小鼠卵母细胞成熟的影响及其在调控卵母细胞成熟中与丝裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)和成熟促进因子(maturation promoting factor,MPF)的上下游关系。c-erbB2反义寡脱氧核苷酸(antisense oligodeoxynucleotide,ASODN)和c-mybASODN均呈剂量依赖方式抑制卵母细胞的生发泡破裂(germinal vesicle breakdown,GVBD)率和第一极体(first polar body,PB1)排放率,并显著延迟其成熟时间。小鼠卵母细胞显微注射重组人c-erbB2蛋白和c-myb蛋白后,培养6h其GVBD率分别比对照组上升了23.1%(P<0.05)和32.2%(P<0.05),培养12h其PB1排放率分别比对照组上升了17.3%(P<0.05)和23.5%(P<0.05)。RT-PCR结果显示,小鼠卵母细胞中存在c-erbB2mRNA和c-mybmRNA表达;c-erbB2ASODN能明显抑制卵母细胞中c-erbB2mRNA和c-mybmRNA的表达,c-mybASODN能明显抑制卵母细胞中c-mybmRNA的表达,对c-erbB2mRNA无明显影响;MAPK抑制剂PD98059以及MPF抑制剂roscovitine在抑制卵母细胞成熟的同时,均能阻断显微注射重组人c-erbB2蛋白和重组人c-myb蛋白对卵母细胞成熟的促进作用,但对卵母细胞中c-erbB2mRNA和c-mybmRNA表达无明显影响。Westernblot结果显示,c-erbB2ASODN、c-mybASODN、PD98059、roscovitine均使卵母细胞中MAPK磷酸化水平和cyclinB1含量下降。结果提示,原癌基因c-erbB2、c-myb在卵母细胞成熟中起重要作用,可能是调控卵母细胞成熟中关键蛋白激酶如MAPK、MPF的上游激活物。更多还原

【Abstract】 It is important to study the mechanism of oocyte maturation because oocyte maturation is essential for the female procreation. The present study was designed to observe the effects of protooncogenes c-erbB2 and c-myb on oocyte maturation and the upstream and downstream relationship with mitogen-activated protein kinase (MAPK) and maturation promoting factor (MPF). The investigation was designed as follows: (1) In order to explore the effects of protooncogenes on oocyte maturation, the dose- and time-dependent effects of c-erbB2 antisense oligodeoxynucleotide (ASODN) and c-myb ASODN on oocyte maturation were examined, and the effects of oocyte microinjection with recombinant c-erbB2 and c-myb proteins on oocyte maturation were investigated; (2) In order to study the upstream and downstream relationship among protooncogenes of c-erbB2, c-myb and protein kinases of MAPK and MPF in regulating oocyte maturation, mouse oocytes were cultured in the medium treated with c-erbB2 ASODN, c-myb ASODN, PD98059 (the MAPK inhibitor) or roscovitine (the MPF inhibitor) for 8 h, respectively, and the expressions of c-erbB2 mRNA, c-myb mRNA, MAPK and MPF were examined. The results showed that both c-erbB2 ASODN and c-myb ASODN inhibited the rate of germinal vesicle breakdown (GVBD) and the first polar (PB1) extrusion of denuded oocytes (DOs) in a dose- and time-dependent way, and delayed their maturation time significantly. When recombinant c-erbB2 and c-myb proteins were microinjected into cytoplasm of germinal vesiclestage oocyte, we found that the GVBD rate increased by 23.1% (P<0.05) and 32.2% (P<0.05), respectively, for 6-hour culture, and the PB1 extrusion rate increased by 17.3% (P<0.05) and 23.5% (P<0.05), respectively, for 12-hour culture. RT-PCR showed that the mRNA expressions of c-erbB2 and c-myb were detected in oocytes; c-erbB2 ASODN inhibited c-erbB2 mRNA and c-myb mRNA expressions; c-myb ASODN inhibited c-myb mRNA expression but had no effect on c-erbB2 mRNA expression. Nonsense tat ODN had no effects on the expressions of c-erbB2 mRNA and c-myb mRNA. Neither PD98059 nor roscovitine changed the expressions of c-erbB2 mRNA and c-myb mRNA though both of them inhibited recombinant c-erbB2 and c-myb proteins-induced oocyte maturation. Furthermore, MAPK phosphorylation and cyclinB1 synthesis in oocytes were inhibited remarkably when oocytes were treated with c-erbB2 ASODN, c-myb ASODN, PD98059 and roscovitine. Nonsense tat ODN had no effects on MAPK phosphorylation and cyclinB1 content. The results suggest that protooncogenes c-erbB2 and c-myb play an important role in oocyte maturation; the effects of c-erbB2 and c- myb depend upon the action of MAPK and MPF, and their activation is the event that occurs downstream of c-erbB2 and c-myb in the maturation signal pathway.更多还原