Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan.
Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka 415-0025, Japan.
Dev Cell. 2016 Apr 18;37(2):148-61. doi: 10.1016/j.devcel.2016.03.013.
During neurulation of chordate ascidians, the 11th mitotic division within the epidermal layer shows a posterior-to-anterior wave that is precisely coordinated with the unidirectional progression of the morphogenetic movement. Here we show that the first sign of this patterned mitosis is an asynchronous anterior-to-posterior S-phase length and that mitotic synchrony is reestablished by a compensatory asynchronous G2-phase length. Live imaging combined with genetic experiments demonstrated that compensatory G2-phase regulation requires transcriptional activation of the G2/M regulator cdc25 by the patterning genes GATA and AP-2. The downregulation of GATA and AP-2 at the onset of neurulation leads to loss of compensatory G2-phase regulation and promotes the transition to patterned mitosis. We propose that such developmentally regulated cell-cycle compensation provides an abrupt switch to spatially patterned mitosis in order to achieve the coordination between mitotic timing and morphogenesis.
在脊索动物海鞘的神经胚形成过程中，表皮层的第 11 次有丝分裂显示出一个从前向后的波，与形态发生运动的单向进展精确协调。在这里，我们表明这种有组织的有丝分裂的第一个迹象是 S 期长度的异步从前向后，并且有丝分裂的同步性通过补偿性的异步 G2 期长度重新建立。活细胞成像与遗传实验相结合表明，补偿性 G2 期调节需要形态发生基因 GATA 和 AP-2 对 G2/M 调节剂 cdc25 的转录激活。神经胚形成开始时 GATA 和 AP-2 的下调导致补偿性 G2 期调节的丧失，并促进向有组织的有丝分裂的转变。我们提出，这种发育调控的细胞周期补偿为空间模式化有丝分裂提供了一个突然的转变，以实现有丝分裂时间和形态发生之间的协调。
