Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv, Israel.
Cell Mol Biol Lett. 2012 Sep;17(3):433-45. doi: 10.2478/s11658-012-0022-7. Epub 2012 Jun 5.
Oocyte maturation in mammals is a multiple-stage process that generates fertilizable oocytes. Ovarian oocytes are arrested at prophase of the first meiotic division characterized by the presence of a germinal vesicle. Towards ovulation, the oocytes resume meiosis and proceed to the second metaphase in a process known as maturation; they undergo nuclear and cytoplasmic changes that are accompanied by translation and degradation of mRNA. Protein phosphatase 1A, magnesium dependent, alpha isoform (PPM1A), which belongs to the metal-dependent serine/threonine protein phosphatase family, is highly conserved during evolution. PPM1A plays a significant role in many cellular functions such as cell cycle progression, apoptosis and cellular differentiation. It works through diverse signaling pathways, including p38 MAP kinase JNK and transforming growth factor beta (TGF-β). Herein we report that PPM1A is expressed in mouse oocytes and that its mRNA level rises during oocyte maturation. Using quantitative real-time polymerase chain reaction (qPCR) and western blot analysis, we found that PPM1A mRNA is synthesized at the beginning of the maturation process and remains elevated in the mature oocytes, promoting the accumulation of PPM1A protein. Since PPM1A function is mainly affected by its level, we propose that it might have an important role in oocyte maturation.
哺乳动物卵母细胞成熟是一个多阶段的过程，可产生可受精的卵母细胞。卵巢卵母细胞在第一次减数分裂的前期停滞，其特征是存在生发泡。在排卵过程中，卵母细胞恢复减数分裂，并在称为成熟的过程中进入第二次 metaphase；它们经历核和细胞质的变化，伴随着 mRNA 的翻译和降解。蛋白磷酸酶 1A，镁依赖性，α 同工型（PPM1A），属于金属依赖性丝氨酸/苏氨酸蛋白磷酸酶家族，在进化过程中高度保守。PPM1A 在许多细胞功能中发挥重要作用，如细胞周期进展、细胞凋亡和细胞分化。它通过多种信号通路发挥作用，包括 p38 MAP 激酶 JNK 和转化生长因子-β（TGF-β）。本文报道 PPM1A 在小鼠卵母细胞中表达，其 mRNA 水平在卵母细胞成熟过程中升高。通过定量实时聚合酶链反应（qPCR）和 Western blot 分析，我们发现 PPM1A mRNA 在成熟过程开始时合成，并在成熟卵母细胞中保持升高，促进 PPM1A 蛋白的积累。由于 PPM1A 的功能主要受其水平的影响，我们提出它可能在卵母细胞成熟中具有重要作用。
