Masui Yoshio
Department of Zoology, University of Toronto, 25 Harbord St., Ontario, Canada M5S 1A1.
Dev Growth Differ. 1991 Dec;33(6):543-551. doi: 10.1111/j.1440-169X.1991.00543.x.
Cytostatic Factor (CSF) is a cytoplasmic factor found in unfertilized eggs of the frog that causes metaphase arrest of cell cycles in the oocyte and zygote. CSF appears in maturing oocyte cytoplasm, but disappears during egg activation. CSF-injected zygotes are arrested at metaphase and show morphology and cellular activities strikingly similar to those of unfertilized eggs. Fresh cytosols extracted from unfertilized eggs contain unstable CSF, called "primary" CSF, which is highly sensitive to Ca ions. Cytosols incubated with Ca ions develop stable CSF, called "secondary" CSF, which is resistant to Ca ions. It has been hypothesized that primary CSF is responsible for the metaphase arrest of meiosis in the unfertilized egg, and its inactivation by a surge of Ca ions during fertilization releases the egg from metaphase arrest. Studies of molecular characteristics of partially purified primary and secondary CSFs suggest that they are both proteins. Recent studies in other laboratories indicate that primary CSF is the c-mos proto-oncogene product. The effect of CSF appears to be primarily stabilization of maturation-promoting factor (MPF), another oocyte cytoplasmic factor, that causes transition of the cell from interphase to metaphase. This paper will summarize the studies on CSF in the author's laboratory over the past 20 years, describe the development of the concept of CSF as a cell cycle regulator, and speculate on the mechanism of its action based on current knowledge.
细胞静止因子（CSF）是在青蛙未受精卵中发现的一种细胞质因子，它会导致卵母细胞和受精卵的细胞周期中期停滞。CSF出现在成熟卵母细胞的细胞质中，但在卵子激活过程中消失。注射了CSF的受精卵停滞在中期，其形态和细胞活动与未受精卵惊人地相似。从未受精卵中提取的新鲜胞质溶胶含有不稳定的CSF，称为“初级”CSF，它对钙离子高度敏感。与钙离子一起孵育的胞质溶胶会产生稳定的CSF，称为“次级”CSF，它对钙离子具有抗性。据推测，初级CSF负责未受精卵减数分裂的中期停滞，受精过程中钙离子的激增使其失活，从而使卵子从中期停滞中释放出来。对部分纯化的初级和次级CSF分子特性的研究表明它们都是蛋白质。其他实验室最近的研究表明，初级CSF是c-mos原癌基因产物。CSF的作用似乎主要是稳定成熟促进因子（MPF），MPF是另一种卵母细胞细胞质因子，它会导致细胞从间期过渡到中期。本文将总结作者实验室过去20年对CSF的研究，描述CSF作为细胞周期调节因子这一概念的发展，并根据现有知识推测其作用机制。
