Miyara F, Pesty A, Migne C, Djediat C, Huang X B, Dumont-Hassan M, Debey P, Lefèvre B
INRA, UMR 1198, INRA Domaine de Vilvert, Jouy en Josas Cedex, France.
Mol Reprod Dev. 2008 Feb;75(2):392-402. doi: 10.1002/mrd.20749.
Our aim was to investigate if human oocytes, like mouse oocytes, exhibit spontaneous Ca(2+) oscillations and nuclear translocation of PLC-beta1 prior to germinal vesicle breakdown (GVBD), and to correlate these events with the evolution of chromatin configuration as a landmark for the meiosis resumption kinetics. Human germinal vesicle (GV) oocytes were either loaded with Fluo-3 probe to record Ca(2+) signals or fixed for subsequent fluorescent labeling of both chromatin and PLC-beta1, and immunogold labeling of PLC-beta1. Here for the first time, we show that human oocytes at the GV-stage exhibit spontaneous Ca(2+) oscillations. Interestingly, only oocytes with a large diameter and characterized by a compact chromatin surrounding the nucleolus of the GV could reveal these kind of oscillations. We also observed a translocation of PLC-beta1 from the cytoplasm towards the nucleus during in vitro maturation of human oocytes. Spontaneous calcium oscillations and nuclear translocation of PLC-beta1 may reflect some degree of oocyte maturity. The impact of our results may be very helpful to understand and resolve many enigmatic problems usually encountered during the in vitro meiotic maturation of human GV oocytes.
我们的目的是研究人类卵母细胞是否像小鼠卵母细胞一样，在生发泡破裂（GVBD）之前表现出自发性Ca(2+)振荡和PLC-β1的核转位，并将这些事件与染色质构型的演变相关联，作为减数分裂恢复动力学的一个标志。人类生发泡（GV）卵母细胞要么用Fluo-3探针加载以记录Ca(2+)信号，要么固定用于随后对染色质和PLC-β1进行荧光标记，以及对PLC-β1进行免疫金标记。在此，我们首次表明处于GV期的人类卵母细胞表现出自发性Ca(2+)振荡。有趣的是，只有直径较大且以围绕GV核仁的致密染色质为特征的卵母细胞才能显示出这类振荡。我们还观察到在人类卵母细胞体外成熟过程中，PLC-β1从细胞质向细胞核的转位。自发性钙振荡和PLC-β1的核转位可能反映了一定程度的卵母细胞成熟度。我们结果的影响可能对理解和解决人类GV卵母细胞体外减数分裂成熟过程中通常遇到的许多神秘问题非常有帮助。
