A novel homeobox gene, dharma, can induce the organizer in a non-cell-autonomous manner
- Yojiro Yamanaka1,
- Toshiro Mizuno2,
- Yoshiki Sasai3,
- Masashi Kishi3,
- Hiroyuki Takeda2,
- Cheol-Hee Kim1,
- Masahiko Hibi1, and
- Toshio Hirano1,4
- 1Division of Molecular Oncology, Biomedical Research Center, Osaka University Medical School; Osaka 565-0871, Japan; 2Department of Molecular Biology, School of Science, Nagoya University, Nagoya 464-8602, Japan; 3Department of Medical Embryology and Neurobiology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8315, Japan
Abstract
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, dharmaexpressed 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.
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Footnotes
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↵4 Corresponding author.
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E-MAIL hirano{at}molonc.med.osaka-u.ac.jp; FAX 81-6-879-3889.
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- Received March 30, 1998.
- Accepted June 3, 1998.
- Cold Spring Harbor Laboratory Press
