アフリカツメガエルの中胚葉誘導と神経誘導シグナリング

 

 

  1. Spemann organizer transcriptome induction by early beta-catenin, Wnt, Nodal, and Siamois signals in Xenopus laevis  Yi Ding, Diego Ploper, Eric A. Sosa, +5, and Edward M. De Robertis ederobertis@mednet.ucla.eduAuthors Info & Affiliations Contributed by Edward M. De Robertis, February 24, 2017 (sent for review January 17, 2017; reviewed by Juan Larraín and Stefano Piccolo) March 27, 2017 114 (15) E3081-E3090 https://doi.org/10.1073/pnas.1700766114　https://www.pnas.org/doi/full/10.1073/pnas.1700766114　
  2. The Xenopus homeobox gene Twin mediates Wnt induction of Goosecoid in establishment of Spemann’s organizer Micheline N. Laurent,, Ira L. Blitz, Chikara Hashimoto, Ute Rothbacher, Ken W.-Y. Cho Author and article information Development　01 December 1997　A dorsal determinant model for establishment of Spemann’s organizer in the dorsal marginal zone. Dorsal determinants, perhaps components of the Wnt signaling pathway, are localized in the vegetal hemisphere of the unfertilized egg (left). During normal development, fertilization triggers the displacement of these determinants toward the future dorsal side (top right). We propose that cells comprising the prospective dorsal mesoendoderm directly inherit these determinants which activate a Wnt-signaling cascade to establish Spemann’s organizer. Activation of a Wnt-signaling cascade leads to establishment ofXtwn expression in the dorsal marginal zone. Xtwn directly binds to the Wnt-responsive element of the gsc promoter (the PE), and in collaboration with activin/BVg1-like signals, activates expression of gsc. Treatments that inhibit cortical rotation (e.g. UV irradiation) result in ‘trapping’ of the dorsal determinants (lower right) in the extreme vegetal endoderm. As a consequence of the lack of distribution of dorsal determinants to the dorsal side, the entire marginal zone becomes specified as ventral mesoderm, no organizer is formed and dorsal-specific marker genes are not expressed ‘dorsally’. Xtwn expression is instead found in the vegetal pole region. Abbr: VM, ventral mesoderm; IM, intermediate mesoderm; Org, organizer.