Induction of precocious germinal vesicle breakdown (GVB) by GVB-incompetent mouse oocytes: possible role of mitogen-activated protein kinases rather than p34cdc2 kinase.
Induction of precocious germinal vesicle breakdown (GVB) by GVB-incompetent mouse oocytes: possible role of mitogen-activated protein kinases rather than p34cdc2 kinase.
复制标题
DOI：
10.1095/biolreprod52.4.895
复制
发表时间：
1995-04
影响因子：
3.6
通讯作者：
Franck Chesnel;J. Eppig
中科院分区：
文献类型：
--
作者：
Franck Chesnel;J. Eppig
与完全发育的小鼠卵母细胞相反，从腔前卵泡中释放出来的正在生长的卵母细胞不能自发地恢复减数分裂。然而，当这些脱落的生长卵母细胞在对照培养基中孵育2-3天，然后用冈田酸处理时，95%的卵母细胞在24小时内发生了早衰性生发囊泡破裂（GVB）和染色体凝聚。本研究表明，这两个事件显然是通过p34cdc2激酶不依赖的途径发生的，因为只有在卵母细胞经历了冈田酸刺激的GVB后，才检测到该激酶的活性。相比之下，微管相关或丝裂原活化蛋白（MAP）激酶1和2在GVB发生前被激活，其活性水平与卵母细胞发生GVB的百分比相关，表明这些激酶可能在这些实验条件下促进GVB和染色体凝聚。此外，研究表明MAP激酶在体内正常卵母细胞生长过程中积累，但在体外培养的脱毛卵母细胞中没有积累，即使这些卵母细胞能够接受冈田酸刺激的GVB。与p34cdc2不同，MAP激酶的积累需要卵母细胞和颗粒细胞之间密切的物理相互作用，但不是卵母细胞成为gvb胜任的必要条件。因此，如果MAP激酶在正常卵母细胞成熟过程中确实参与了GVB的诱导和染色体凝聚，那么GVB能力的获得需要卵母细胞自主积累MAP激酶激活剂，而不是MAP激酶本身。
In contrast to fully grown mouse oocytes, growing oocytes released from their preantral follicles are not capable of resuming meiosis spontaneously. However, when these denuded growing oocytes are incubated for 2-3 days in control medium and then treated with okadaic acid, 95% undergo precocious germinal vesicle breakdown (GVB) and chromosome condensation within 24 h. This study shows that both events apparently occur through a p34cdc2 kinase-independent pathway, since activity of this kinase was detected only after the oocytes had undergone okadaic acid-stimulated GVB. In contrast, microtubule-associated or mitogen-activated protein (MAP) kinases 1 and 2 were activated before GVB and their level of activity was correlated with the percentage of oocytes undergoing GVB, suggesting that these kinases may promote GVB and chromosome condensation under these experimental conditions. In addition, it is shown that MAP kinases accumulate during normal oocyte growth in vivo, but not in cultured denuded oocytes in vitro even when these oocytes become competent to undergo okadaic acid-stimulated GVB. Unlike p34cdc2, the accumulation of MAP kinases requires close physical interactions between the oocytes and the granulosa cells but is not necessary for the oocyte to become GVB-competent. Therefore, it MAP kinases are actually involved in the induction of GVB and chromosome condensation during normal oocyte maturation, acquisition of GVB competence requires oocyte-autonomous accumulation of MAP kinase activator(s) rather than the MAP kinases themselves.