Establishment of the dorsal-ventral axis in Xenopus embryos coincides with the dorsal enrichment of dishevelled that is dependent on cortical rotation.
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.
Miller
J R
JR
Howard Hughes Medical Institute, Department of Pharmacology, and Center for Developmental Biology, University of Washington School of Medicine, Seattle, Washington 98195, USA.
Rowning
B A
BA
Larabell
C A
CA
Yang-Snyder
J A
JA
Bates
R L
RL
Moon
R T
RT
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000528:radiation effects; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism; D019521:Body Patterning / Q000187:drug effects / Q000528:radiation effects; D002454:Cell Differentiation / Q000187:drug effects / Q000528:radiation effects; D016764:Cell Polarity / Q000187:drug effects / Q000528:radiation effects; D003598:Cytoskeletal Proteins / Q000378:metabolism; D017666:Deuterium Oxide / Q000494:pharmacology; D000072261:Dishevelled Proteins; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D047108:Embryonic Development; D051157:Frizzled Receptors; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D015739:Nocodazole / Q000494:pharmacology; D015388:Organelles / Q000187:drug effects / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators; D014466:Ultraviolet Rays; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology / Q000378:metabolism; D015053:Zygote / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D051176:beta Catenin
D048868:Adaptor Proteins, Signal Transducing; C495266:CTNNB1 protein, Xenopus; C495268:Ctnnb1 protein, rat; D003598:Cytoskeletal Proteins; C000606586:DVL1 protein, Xenopus; D000072261:Dishevelled Proteins; C489741:FZD1 protein, Xenopus; D051157:Frizzled Receptors; D010750:Phosphoproteins; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D029867:Xenopus Proteins; D051176:beta Catenin; C078603:Fzd1 protein, rat; D017666:Deuterium Oxide; D015739:Nocodazole