Zebrafish Dkk1 Functions in Forebrain Specification and Axial Mesendoderm Formation

Zebrafish Dkk1 Functions in Forebrain Specification and Axial Mesendoderm Formation We identified a zebrafish homologue of Dickkopf-1 (Dkk1), which was previously identified in Xenopus as a Wnt inhibitor with potent head-inducing activity. Zebrafish dkk1 is expressed in the dorsal marginal blastoderm and also in the dorsal yolk syncytial layer after mid-blastula transition. At later blastula stages, the expression expands to the entire blastoderm margin. During gastrulation, dkk1 -expressing cells are confined to the embryonic shield and later to the anterior axial mesendoderm, prospective prechordal plate. Embryos, in which dkk1 was ectopically expressed, exhibited enlarged forebrain, eyes, and axial mesendoderm such as prechordal plate and notochord. dkk1 expression in the dorso-anterior mesendoderm during gastrulation was prominently reduced in zebrafish mutants bozozok ( boz ), squint ( sqt ), and one-eyed pinhead ( oep ), which all display abnormalities in the formation and function of the Spemann organizer and axial mesendoderm. dkk1 expression was normal in these embryos during the blastula period, indicating that zygotic functions of these genes are required for maintenance but not establishment of dkk1 expression. Overexpression of dkk1 suppressed defects in the development of forebrain, eyes, and notochord in boz mutants. Overexpression of dkk1 promoted anterior neuroectoderm development in the embryos injected with antivin RNA, which lack most of the mesoderm and endoderm, suggesting that Dkk1 can affect regionalization of neuroectoderm independently of dorso-anterior mesendoderm. These data indicate that Dkk1, expressed in dorsal mesendoderm, functions in the formation of both the anterior nervous system and the axial mesendoderm in zebrafish. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Developmental Biology Elsevier

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Publisher
Elsevier
Copyright
Copyright © 2000 Academic Press
ISSN
0012-1606
eISSN
1095-564X
DOI
10.1006/dbio.1999.9537
pmid
10625541
Publisher site
See Article on Publisher Site

Abstract

We identified a zebrafish homologue of Dickkopf-1 (Dkk1), which was previously identified in Xenopus as a Wnt inhibitor with potent head-inducing activity. Zebrafish dkk1 is expressed in the dorsal marginal blastoderm and also in the dorsal yolk syncytial layer after mid-blastula transition. At later blastula stages, the expression expands to the entire blastoderm margin. During gastrulation, dkk1 -expressing cells are confined to the embryonic shield and later to the anterior axial mesendoderm, prospective prechordal plate. Embryos, in which dkk1 was ectopically expressed, exhibited enlarged forebrain, eyes, and axial mesendoderm such as prechordal plate and notochord. dkk1 expression in the dorso-anterior mesendoderm during gastrulation was prominently reduced in zebrafish mutants bozozok ( boz ), squint ( sqt ), and one-eyed pinhead ( oep ), which all display abnormalities in the formation and function of the Spemann organizer and axial mesendoderm. dkk1 expression was normal in these embryos during the blastula period, indicating that zygotic functions of these genes are required for maintenance but not establishment of dkk1 expression. Overexpression of dkk1 suppressed defects in the development of forebrain, eyes, and notochord in boz mutants. Overexpression of dkk1 promoted anterior neuroectoderm development in the embryos injected with antivin RNA, which lack most of the mesoderm and endoderm, suggesting that Dkk1 can affect regionalization of neuroectoderm independently of dorso-anterior mesendoderm. These data indicate that Dkk1, expressed in dorsal mesendoderm, functions in the formation of both the anterior nervous system and the axial mesendoderm in zebrafish.

Journal

Developmental BiologyElsevier

Published: Jan 1, 2000

References

  • Murine cerberus homologue mCer-1: A candidate anterior patterning molecule
    Biben, C.; Stanley, E.; Fabri, L.; Kotecha, S.; Rhinn, M.; Drinkwater, C.; Lah, M.; Wang, C.C.; Nash, A.; Hilton, D.; Ang, S.L.; Mohun, T.; Harvey, R.P.
  • Wnt signaling: Why is everything so negative
    Brown, J.D.; Moon, R.T.
  • Zebrafish nodal-related 2 encodes an early mesendodermal inducer signaling from the extraembryonic yolk syncytial layer
    Erter, C.E.; Solnica-Krezel, L.; Wright, C.V.
  • The function of silberblick in the positioning of the eye anlage in zebrafish embryo
    Heisenberg, C.P.; Nüsslein-Volhard, C.
  • The nieuwkoid gene characterizes and mediates a Nieuwkoop-center-like activity in the zebrafish
    Koos, D.S.; Ho, R.K.
  • Specification of the anteroposterior neural axis through synergistic interaction of the Wnt signaling cascade with noggin and follistatin
    McGrew, L.L.; Lai, C.J.; Moon, R.T.
  • Differential regulation of chordin expression domains in mutant zebrafish
    Miller-Bertoglio, V.E.; Fisher, S.; Sanchez, A.; Mullins, M.C.; Halpern, M.E.
  • Zebrafish nodal-related genes are implicated in axial patterning and establishing left-right asymmetry
    Rebagliati, M.R.; Toyama, R.; Fricke, C.; Haffter, P.; Dawid, I.B.
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    Sasai, Y.; De Robertis, E.M.

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