The zebrafish bozozok locus encodes Dharma, a homeodomain protein essential for induction of gastrula organizer and dorsoanterior embryonic structures

Kimberly Fekany, Yojiro Yamanaka, TinChung Leung, Howard I. Sirotkin, Jacek Topczewski, Michael A. Gates, Masahiko Hibi, Armand Renucci, Derek Stemple, Andy Radbill, Alexander F. Schier, Wolfgang Driever, Toshio Hirano, William S. Talbot, Lilianna Solnica-Krezel*

*Corresponding author for this work

Research output: Contribution to journalArticle

170 Scopus citations

Abstract

The dorsal gastrula organizer plays a fundamental role in establishment of the vertebrate axis. We demonstrate that the zebrafish bozozok (boz) locus is required at the blastula stages for formation of the embryonic shield, the equivalent of the gastrula organizer and expression of multiple organizer-specific genes. Furthermore, boz is essential for specification of dorsoanterior embryonic structures, including notochord, prechordal mesendoderm, floor plate and forebrain. We report that boz mutations disrupt the homeobox gene dharma. Overexpression of boz in the extraembryonic yolk syncytial layer of boz mutant embryos is sufficient for normal development of the overlying blastoderm, revealing an involvement of extraembryonic structures in anterior patterning in fish similarly to murine embryos. Epistatic analyses indicate that boz acts downstream of β-catenin and upstream to TGF-β signaling or in a parallel pathway. These studies provide genetic evidence for an essential function of a homeodomain protein in β-catenin-mediated induction of the dorsal gastrula organizer and place boz at the top of a hierarchy of zygotic genes specifying the dorsal midline of a vertebrate embryo.

Original languageEnglish (US)
Pages (from-to)1427-1438
Number of pages12
JournalDevelopment
Volume126
Issue number7
StatePublished - Apr 1999

Keywords

  • A-P patterning
  • Axis
  • Dorsal forerunner cells
  • Nieuwkoop center
  • Notochord
  • Prechordal mesendoderm
  • Spemann organizer
  • bozozok

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology

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    Fekany, K., Yamanaka, Y., Leung, T., Sirotkin, H. I., Topczewski, J., Gates, M. A., Hibi, M., Renucci, A., Stemple, D., Radbill, A., Schier, A. F., Driever, W., Hirano, T., Talbot, W. S., & Solnica-Krezel, L. (1999). The zebrafish bozozok locus encodes Dharma, a homeodomain protein essential for induction of gastrula organizer and dorsoanterior embryonic structures. Development, 126(7), 1427-1438.