The zebrafish midblastula transition.
The zebrafish midblastula transition.
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作者：
D. Kane;C. Kimmel
斑马鱼的中囊胚转变（MBT）开始于周期10。其特征是细胞周期延长、细胞同步性丧失、转录激活和细胞运动性出现。核质比取代了控制前9个周期的15分钟振荡器，似乎控制了MBT。这种定时机制是细胞自主运作的：标记细胞的克隆启动细胞周期延长独立于邻居，但依赖于直系祖先。当不平等分裂发生时，根据每个子代的体积产生不对称的细胞周期延长。在MBT开始后的几个周期中，周期长度与卵裂球体积的倒数相关，表明在我们称之为“MBT期”的间隔内，核质比继续调节细胞周期。
The zebrafish midblastula transition (MBT) begins at cycle 10. It is characterized by cell cycle lengthening, loss of cell synchrony, activation of transcription and appearance of cell motility. Superceding a 15 minute oscillator that controls the first nine cycles, the nucleocytoplasmic ratio appears to govern the MBT. This timing mechanism operates cell autonomously: clones of labeled cells initiate cell cycle lengthening independently of neighbors but dependent on immediate lineal ancestors. Unequal divisions, when they occur, produce asymmetric cell cycle lengthening based on the volume of each daughter. During the several cycles after the MBT begins, cycle length is correlated with the reciprocal of the blastomere volume, suggesting a continuation of cell cycle regulation by the nucleocytoplasmic ratio during an interval that we term the 'MBT period'.