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Link to original content: https://doi.org/10.1007/s00427-004-0390-8
The Trox-2 Hox/ParaHox gene of Trichoplax (Placozoa) marks an epithelial boundary | Development Genes and Evolution Skip to main content
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The Trox-2 Hox/ParaHox gene of Trichoplax (Placozoa) marks an epithelial boundary

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Abstract

Hox and ParaHox genes are implicated in axial patterning of cnidarians and bilaterians, and are thought to have originated by tandem duplication of a single “ProtoHox” gene followed by duplication of the resultant gene cluster. It is unclear what the ancestral role of Hox/ParaHox genes was before the divergence of Cnidaria and Bilateria, or what roles the postulated ProtoHox gene(s) played. Here we describe the full coding region, spatial expression and function of Trox-2, the single Hox/ParaHox-type gene identified in Trichoplax adhaerens (phylum Placozoa) and either a candidate ProtoHox or a ParaHox gene. Trox-2 is expressed in a ring around the periphery of Trichoplax, in small cells located between the outer margins of the upper and lower epithelial cell layers. Inhibition of Trox-2 function, either by uptake of morpholino antisense oligonucleotides or by RNA interference, causes complete cessation of growth and binary fission. We speculate that Trox-2 functions within a hitherto unrecognized population of possibly multipotential peripheral stem cells that contribute to differentiated cells at the epithelial boundary of Trichoplax.

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Acknowledgements

This work was supported by the German Science Foundation, (DFG Schi 277/10-2), the Human Frontier Science Program (HFSP RGP0221/2001-M), and the Graduiertenförderung Niedersachsen (fellowship to W.J.). We are grateful to Jutta Bunnenberg for technical assistance, and two anonymous reviewers for valuable and constructive comments.

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Authors and Affiliations

  1. ITZ, Ecology and Evolution, TiHo Hannover, Bünteweg 17d, 30559, Hannover, Germany

    Wolfgang Jakob, Sven Sagasser & Bernd Schierwater

  2. MCDB, Yale University, 165 Prospect St., New Haven, CT 06520, USA

    Stephen Dellaporta & Bernd Schierwater

  3. Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK

    Peter Holland

  4. Ecology and Evolution, J.W. Goethe-Universität, Siesmayerstrasse 70, 60054, Frankfurt, Germany

    Kerstin Kuhn

Authors
  1. Wolfgang Jakob
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  2. Sven Sagasser
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  3. Stephen Dellaporta
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  4. Peter Holland
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  5. Kerstin Kuhn
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  6. Bernd Schierwater
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Correspondence to Bernd Schierwater.

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Edited by D. Tautz

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Jakob, W., Sagasser, S., Dellaporta, S. et al. The Trox-2 Hox/ParaHox gene of Trichoplax (Placozoa) marks an epithelial boundary. Dev Genes Evol 214, 170–175 (2004). https://doi.org/10.1007/s00427-004-0390-8

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  • DOI: https://doi.org/10.1007/s00427-004-0390-8

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