A novel homeobox gene, dharma, can induce the organizer in a non-cell-autonomous manner.

The formation of Spemann organizer is one of the most important steps in dorsoventral axis determination in vertebrate development. However, whether the organizer forms autonomously or is induced non-cell-autonomously is controversial. In this report we have isolated a novel zebrafish homeobox gene, dharma, capable of inducing the organizer ectopically. The expression of dharma was first detected in several blastomeres at one side of the margin soon after the mid-blastula transition and continued in the dorsal side of the yolk syncytial layer (YSL) under the embryonic shield, the zebrafish organizer, until the onset of gastrulation. Furthermore, dharma expressed in the YSL induced the organizer in a non-cell-autonomous manner. These results provided the first identification of a zygotic gene to be implicated in the formation of an organizer-inducing center.

[1]  T. Hirano,et al.  [Axis formation in zebrafish]. , 2000, Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme.

[2]  Walter Birchmeier,et al.  Hot papers in cell biology - J. Behrens, J.P. von Kries, M. Kuehl, L. Bruhn, D. Wedlich, R. Grosschedl, W. Birchmeier: "Functional interaction of beta-catenin with the transcription factor LEF-1" - Comments by Walter Birchmeier , 1999 .

[3]  R. Nusse,et al.  Wnt signaling: a common theme in animal development. , 1997, Genes & development.

[4]  Ken W. Y. Cho,et al.  The Xenopus homeobox gene twin mediates Wnt induction of goosecoid in establishment of Spemann's organizer. , 1997, Development.

[5]  J. Heasman Patterning the Xenopus blastula. , 1997, Development.

[6]  P. Lemaire,et al.  Animal and vegetal pole cells of early Xenopus embryos respond differently to maternal dorsal determinants: implications for the patterning of the organiser. , 1997, Development.

[7]  R. Moon,et al.  WNTs modulate cell fate and behavior during vertebrate development. , 1997, Trends in genetics : TIG.

[8]  R. Moon,et al.  Structurally Related Receptors and Antagonists Compete for Secreted Wnt Ligands , 1997, Cell.

[9]  C. Larabell,et al.  Establishment of the Dorso-ventral Axis in Xenopus Embryos Is Presaged by Early Asymmetries in β-Catenin That Are Modulated by the Wnt Signaling Pathway , 1997, The Journal of cell biology.

[10]  Y. Sasai,et al.  Ectodermal patterning in vertebrate embryos. , 1997, Developmental biology.

[11]  M. S. Cooper,et al.  Spatially distinct domains of cell behavior in the zebrafish organizer region. , 1997, Biochemistry and cell biology = Biochimie et biologie cellulaire.

[12]  C. Larabell Establishment of the dorsoventral axis in Xenopus embryos is presaged by early asymmetries in β-catenin that are modulated by the Wnt signaling pathway , 1997 .

[13]  P. Lemaire,et al.  The vertebrate organizer: structure and molecules. , 1996, Trends in genetics : TIG.

[14]  D A Kane,et al.  Genes establishing dorsoventral pattern formation in the zebrafish embryo: the ventral specifying genes. , 1996, Development.

[15]  M. S. Cooper,et al.  A cluster of noninvoluting endocytic cells at the margin of the zebrafish blastoderm marks the site of embryonic shield formation. , 1996, Developmental biology.

[16]  A. McMahon,et al.  Genetic analysis of dorsoventral pattern formation in the zebrafish: requirement of a BMP-like ventralizing activity and its dorsal repressor. , 1996, Genes & development.

[17]  M. Hosobuchi,et al.  Maternal beta-catenin establishes a 'dorsal signal' in early Xenopus embryos. , 1996, Development.

[18]  A. Kuroiwa,et al.  Mesoderm induction in zebrafish , 1996, Nature.

[19]  Michael Kühl,et al.  Functional interaction of β-catenin with the transcription factor LEF-1 , 1996, Nature.

[20]  Hans Clevers,et al.  XTcf-3 Transcription Factor Mediates β-Catenin-Induced Axis Formation in Xenopus Embryos , 1996, Cell.

[21]  D. Melton,et al.  A molecular mechanism for the effect of lithium on development. , 1996, Proceedings of the National Academy of Sciences of the United States of America.

[22]  M. Sakai The vegetal determinants required for the Spemann organizer move equatorially during the first cell cycle. , 1996, Development.

[23]  H. Steinbeisser,et al.  β-catenin translocation into nuclei demarcates the dorsalizing centers in frog and fish embryos , 1996, Mechanisms of Development.

[24]  H. Sive,et al.  Anteroposterior patterning in the zebrafish, Danio rerio: an explant assay reveals inductive and suppressive cell interactions. , 1996, Development.

[25]  W. Driever Axis formation in zebrafish. , 1995, Current opinion in genetics & development.

[26]  P. Lemaire,et al.  Expression cloning of Siamois, a xenopus homeobox gene expressed in dorsal-vegetal cells of blastulae and able to induce a complete secondary axis , 1995, Cell.

[27]  P. Lemaire,et al.  A role for cytoplasmic determinants in mesoderm patterning: cell-autonomous activation of the goosecoid and Xwnt-8 genes along the dorsoventral axis of early Xenopus embryos. , 1994, Development.

[28]  S. Moody,et al.  The cleavage stage origin of Spemann's Organizer: analysis of the movements of blastomere clones before and during gastrulation in Xenopus. , 1994, Development.

[29]  E M De Robertis,et al.  Expression of zebrafish goosecoid and no tail gene products in wild-type and mutant no tail embryos. , 1994, Development.

[30]  L. Lettice,et al.  Whole-mount in situ hybridizations on zebrafish embryos using a mixture of digoxigenin- and fluorescein-labelled probes. , 1994, Trends in genetics : TIG.

[31]  J. Slack Inducing factors in Xenopus early embryos , 1994, Current Biology.

[32]  D. Grunwald,et al.  Lithium perturbation and goosecoid expression identify a dorsal specification pathway in the pregastrula zebrafish. , 1993, Development.

[33]  R. Ho,et al.  The protein product of the zebrafish homologue of the mouse T gene is expressed in nuclei of the germ ring and the notochord of the early embryo. , 1992, Development.

[34]  William C. Smith,et al.  Expression cloning of noggin, a new dorsalizing factor localized to the Spemann organizer in Xenopus embryos , 1992, Cell.

[35]  P. Good,et al.  The LIM domain-containing homeo box gene Xlim-1 is expressed specifically in the organizer region of Xenopus gastrula embryos. , 1992, Genes & development.

[36]  Ken W. Y. Cho,et al.  Molecular nature of Spemann's organizer: the role of the Xenopus homeobox gene goosecoid , 1991, Cell.

[37]  R. Harland,et al.  Injected Xwnt-8 RNA acts early in Xenopus embryos to promote formation of a vegetal dorsalizing center , 1991, Cell.

[38]  S. Moody,et al.  Autonomous differentiation of dorsal axial structures from an animal cap cleavage stage blastomere in Xenopus. , 1991, Development.

[39]  H. Kageura Spatial distribution of the capacity to initiate a secondary embryo in the 32-cell embryo of Xenopus laevis. , 1990, Developmental biology.

[40]  E. Jones,et al.  The development of animal cap cells in Xenopus: a measure of the start of animal cap competence to form mesoderm , 1987 .

[41]  H. Takasaki Fates and Roles of the Presumptive Organizer Region in the 32‐cell Embryo in Normal Development of Xenopus laevis , 1987 .

[42]  R. Gimlich Acquisition of developmental autonomy in the equatorial region of the Xenopus embryo. , 1986, Developmental biology.

[43]  J. Gerhart,et al.  Early cellular interactions promote embryonic axis formation in Xenopus laevis. , 1984, Developmental biology.