Taylor M A, Smith L D
Dev Biol. 1987 May;121(1):111-8. doi: 10.1016/0012-1606(87)90144-8.
The competence of Xenopus laevis oocytes in various stages of growth to respond to progesterone treatment was investigated. Full-grown (stage 6) oocytes undergo nuclear membrane dissolution and resume meiosis in response to progesterone exposure, while smaller oocytes (stages 3-5; less than 1100 micron in diameter) do not. The defect which prevents 750- to 1050-micron oocytes from responding to progesterone can be overcome by microinjecting cytoplasm withdrawn from a stage 6 oocyte. Germinal vesicle breakdown in these small oocytes occurs on a timetable similar to that of stage 6 oocytes exposed to progesterone and is accompanied by a twofold increase in protein synthesis as well as the activation of MPF. The results argue that a cytoplasmic factor(s) which probably first appears at late stage 5 is required for progesterone responsiveness. The identity and role of the factor(s) in the development of maturation competence and the regulation of maternal mRNA translation are discussed.
研究了非洲爪蟾卵母细胞在不同生长阶段对孕酮处理的反应能力。成熟（6期）卵母细胞在暴露于孕酮时会经历核膜溶解并恢复减数分裂，而较小的卵母细胞（3 - 5期；直径小于1100微米）则不会。通过显微注射从6期卵母细胞中提取的细胞质，可以克服阻止750至1050微米卵母细胞对孕酮作出反应的缺陷。这些小卵母细胞中的生发泡破裂发生的时间进程与暴露于孕酮的6期卵母细胞相似，并伴随着蛋白质合成增加两倍以及MPF的激活。结果表明，孕酮反应性需要一种可能在5期末首次出现的细胞质因子。讨论了该因子在成熟能力发展和母体mRNA翻译调控中的身份和作用。
