Avazeri N, Pesty A, Lefèvre B
Institut national de la santé et de la recherche médicale Unité 355, Clamart, France.
Reprod Nutr Dev. 1998 Nov-Dec;38(6):671-82. doi: 10.1051/rnd:19980609.
The role of the nuclear phosphoinositide (PI) cycle during meiotic resumption in mouse oocytes was examined. First, using indirect immunofluorescence staining with specific monoclonal antibodies (mAbs) against elements of this cycle, the presence of inositol trisphosphate receptors (IP3Rs) (IP3R-1 or IP3R-3) or phosphoinositide-phospholipase (PLC) isoforms (PLC beta 1 or PLC gamma 1) was monitored in the germinal vesicle (GV). Using confocal laser scanning microscopy, we analysed the effects of the nuclear microinjection of these antibodies on both spontaneous nuclear calcium oscillations and meiosis resumption. Immunostainings showed that IP3R-1 and PLC beta 1 isoforms were both present in the GV, whereas IP3R-3 and PLC gamma 1 isoforms were not. The anti-IP3R-1 mAbs or the anti-PLC beta 1 mAbs microinjected into the GV, induced inhibition of both the nuclear Ca2+ oscillations and the meiotic process, whereas the anti-IP3R-3 mAbs and the anti-PLC gamma 1 mAbs did not. We concluded that a specific nuclear PI cycle is present in the mouse oocyte and meiosis resumption requires a specific nuclear phosphoinositide-dependent Ca2+ signal.
研究了核磷酸肌醇（PI）循环在小鼠卵母细胞减数分裂恢复过程中的作用。首先，使用针对该循环元件的特异性单克隆抗体（mAb）进行间接免疫荧光染色，监测生发泡（GV）中三磷酸肌醇受体（IP3R）（IP3R-1或IP3R-3）或磷酸肌醇-磷脂酶（PLC）同工型（PLCβ1或PLCγ1）的存在情况。利用共聚焦激光扫描显微镜，我们分析了向细胞核显微注射这些抗体对自发核钙振荡和减数分裂恢复的影响。免疫染色显示，IP3R-1和PLCβ1同工型均存在于GV中，而IP3R-3和PLCγ1同工型则不存在。向GV中显微注射抗IP3R-1 mAb或抗PLCβ1 mAb，可诱导核Ca2+振荡和减数分裂过程受到抑制，而抗IP3R-3 mAb和抗PLCγ1 mAb则无此作用。我们得出结论，小鼠卵母细胞中存在特定的核PI循环，减数分裂恢复需要特定的核磷酸肌醇依赖性Ca2+信号。
