Wang Zhong-Wei, Zhang Guang-Li, Schatten Heide, Carroll John, Sun Qing-Yuan
State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA.
Sci Rep. 2016 Jan 27;6:19827. doi: 10.1038/srep19827.
Spindle sizes are different in diverse species and cell types. In frogs, the meiotic spindle size is positively correlated with the egg cell volume. Across species, relatively small mouse oocytes (70-80 μm) have a relatively large spindle while larger pig oocytes (about 120 μm) have a considerably smaller spindle. In this study we investigated whether species-specific oocyte spindle size was determined by cytoplasmic or nuclear factors. By exchanging the germinal vesicle between mouse and pig oocytes, we obtained two kinds of reconstructed oocytes: one with mouse ooplasm and pig GV (mCy-pGV oocyte), and the other with pig ooplasm and mouse GV (pCy-mGV oocyte). We show that the MII spindle size of the mCy-pGV oocyte is similar to that of the mouse meiotic spindle and significantly larger than that of the pig meiotic spindle. The timing of oocyte maturation also followed that of the species from which the oocyte cytoplasm arose, although some impact of the origin of the GV was observed. These data suggest that spindle size and the timing of meiotic progression are governed by cytoplasmic components rather than cytoplasmic volume and GV materials.
纺锤体的大小在不同物种和细胞类型中有所不同。在青蛙中，减数分裂纺锤体的大小与卵细胞体积呈正相关。在不同物种间，相对较小的小鼠卵母细胞（70 - 80μm）具有相对较大的纺锤体，而较大的猪卵母细胞（约120μm）具有相当小的纺锤体。在本研究中，我们调查了物种特异性卵母细胞纺锤体大小是由细胞质还是核因子决定的。通过交换小鼠和猪卵母细胞之间的生发泡，我们获得了两种重构卵母细胞：一种具有小鼠卵质和猪生发泡（mCy - pGV卵母细胞），另一种具有猪卵质和小鼠生发泡（pCy - mGV卵母细胞）。我们发现，mCy - pGV卵母细胞的MII纺锤体大小与小鼠减数分裂纺锤体相似，且显著大于猪减数分裂纺锤体。卵母细胞成熟的时间也遵循卵母细胞细胞质来源物种的时间，尽管观察到了生发泡来源的一些影响。这些数据表明，纺锤体大小和减数分裂进程的时间是由细胞质成分而非细胞质体积和生发泡物质决定的。
