Chu Francie H, Afonin Bonnie, Gustin Jean K, Bost Alyssa, Sanchez Michael, Domingo Carmen R
Department of Biology, San Francisco State University, San Francisco, California 94132, USA.
Dev Dyn. 2007 Nov;236(11):3007-19. doi: 10.1002/dvdy.21326.
Disruption of axis specification leads to defects in dorsal tissue patterning and cell movements. Here, we examine how beta-catenin coordinately affects gastrulation movements and dorsal mesoderm differentiation. The reduction of beta-catenin protein levels by morpholino oligonucleotides complementary to beta-catenin mRNA causes a disruption in gastrulation movements. Time-lapse imaging of beta-catenin morphants during gastrulation reveals that involution occurs simultaneously around the blastopore in the absence of convergent extension cell movements. Transplantation experiments show that morphant cells grafted from the marginal zone into wild-type hosts differentiate into notochord and muscle. However, wild-type mesoderm cells grafted to the marginal zone of beta-catenin morphants do not form dorsal tissues. These data argue that beta-catenin is not required for the initial establishment of dorsal mesoderm cell competency, but it is required for the maintenance of that competency. We propose that tissue interactions that occur during convergent extension movements are necessary for maintaining dorsal tissue competency.
轴规格的破坏会导致背侧组织模式形成和细胞运动出现缺陷。在此，我们研究β-连环蛋白如何协同影响原肠胚形成运动和背侧中胚层分化。通过与β-连环蛋白mRNA互补的吗啉代寡核苷酸降低β-连环蛋白的蛋白质水平会导致原肠胚形成运动受到破坏。对原肠胚形成期间的β-连环蛋白形态突变体进行延时成像显示，在没有汇聚延伸细胞运动的情况下，内卷在胚孔周围同时发生。移植实验表明，从边缘区移植到野生型宿主中的形态突变体细胞分化为脊索和肌肉。然而，移植到β-连环蛋白形态突变体边缘区的野生型中胚层细胞不会形成背侧组织。这些数据表明，β-连环蛋白对于背侧中胚层细胞能力的初始建立不是必需的，但对于维持该能力是必需的。我们提出，在汇聚延伸运动期间发生的组织相互作用对于维持背侧组织能力是必要的。
