Miller J R, Rowning B A, Larabell C A, Yang-Snyder J A, Bates R L, Moon R T
Howard Hughes Medical Institute, Department of Pharmacology, and Center for Developmental Biology, University of Washington School of Medicine, Seattle, Washington 98195, USA.
J Cell Biol. 1999 Jul 26;146(2):427-37. doi: 10.1083/jcb.146.2.427.
Examination of the subcellular localization of Dishevelled (Dsh) in fertilized Xenopus eggs revealed that Dsh is associated with vesicle-like organelles that are enriched on the prospective dorsal side of the embryo after cortical rotation. Dorsal enrichment of Dsh is blocked by UV irradiation of the vegetal pole, a treatment that inhibits development of dorsal cell fates, linking accumulation of Dsh and specification of dorsal cell fates. Investigation of the dynamics of Dsh localization using Dsh tagged with green fluorescent protein (Dsh-GFP) demonstrated that Dsh-GFP associates with small vesicle-like organelles that are directionally transported along the parallel array of microtubules towards the prospective dorsal side of the embryo during cortical rotation. Perturbing the assembly of the microtubule array with D(2)O, a treatment that promotes the random assembly of the array and the dorsalization of embryos, randomizes translocation of Dsh-GFP. Conversely, UV irradiation of the vegetal pole abolishes movement of Dsh-GFP. Finally, we demonstrate that overexpression of Dsh can stabilize beta-catenin in Xenopus. These data suggest that the directional translocation of Dsh along microtubules during cortical rotation and its subsequent enrichment on the prospective dorsal side of the embryo play a role in locally activating a maternal Wnt pathway responsible for establishing dorsal cell fates in Xenopus.
对非洲爪蟾受精卵中Dishevelled（Dsh）的亚细胞定位进行检测发现，Dsh与囊泡样细胞器相关联，这些细胞器在皮层旋转后富集于胚胎的预期背侧。植物极的紫外线照射会阻断Dsh的背侧富集，这种处理会抑制背侧细胞命运的发育，将Dsh的积累与背侧细胞命运的特化联系起来。使用绿色荧光蛋白标记的Dsh（Dsh-GFP）对Dsh定位动态进行研究表明，在皮层旋转过程中，Dsh-GFP与小囊泡样细胞器相关联，这些细胞器沿微管平行阵列定向运输至胚胎的预期背侧。用重水（D₂O）扰乱微管阵列的组装，这种处理会促进阵列的随机组装和胚胎的背化，使Dsh-GFP的易位随机化。相反，植物极的紫外线照射会消除Dsh-GFP的移动。最后，我们证明在非洲爪蟾中过表达Dsh可以稳定β-连环蛋白。这些数据表明，在皮层旋转过程中Dsh沿微管的定向易位及其随后在胚胎预期背侧的富集，在局部激活负责确立非洲爪蟾背侧细胞命运的母体Wnt信号通路中发挥作用。
