Retinoic acid signaling acts via Hox1 to establish the posterior limit of the pharynx in the chordate amphioxus
Abstract
In the invertebrate chordate amphioxus, as in vertebrates, retinoic acid (RA) specifies position along the anterior/posterior axis with elevated RA signaling in the middle third of the endoderm setting the posterior limit of the pharynx. Here we show that AmphiHox1 is also expressed in the middle third of the developing amphioxus endoderm and is activated by RA signaling. Knockdown of AmphiHox1 function with an antisense morpholino oligonucleotide shows that AmphiHox1 mediates the role of RA signaling in setting the posterior limit of the pharynx by repressing expression of pharyngeal markers in the posterior foregut/midgut endoderm. The spatiotemporal expression of these endodermal genes in embryos treated with RA or the RA antagonist BMS009 indicates that Pax1/9, Pitx and Notch are probably more upstream than Otx and Nodal in the hierarchy of genes repressed by RA signaling. This work highlights the potential of amphioxus, a genomically simple, vertebrate-like invertebrate chordate, as a paradigm for understanding gene hierarchies similar to the more complex ones of vertebrates.
Additional Information
© 2005 The Company of Biologists. Accepted 22 October 2004. We thank J. M. Lawrence (University of South Florida, Tampa, FL, USA) for providing laboratory space during the amphioxus breeding season and H. Gronemeyer (University of Strasbourg, France) for generously providing BMS009. This research was supported by NSF IBN 00-78599 to N.D.H. and L.Z.H., NAG2-1585 from the National Aeronautics and Space Administration to L.Z.H and by grants from the MENRT, the CNRS, the ARC and the Région Rhône-Alpes to V.L. M. Schubert is supported by a European Community Marie Curie Fellowship.Attached Files
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Supplemental Material - FigS1.jpg
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Additional details
- Eprint ID
- 64091
- Resolver ID
- CaltechAUTHORS:20160129-100532917
- IBN 00-78599
- NSF
- NAG2-1585
- NASA
- Ministère de l'Éducation nationale, de l'Enseignement supérieur et de la Recherche (MENRT)
- Centre National de la Recherche Scientifique (CNRS)
- Australian Research Council
- Région Rhône-Alpes
- Marie Curie Fellowship
- Created
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2016-01-29Created from EPrint's datestamp field
- Updated
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2023-10-17Created from EPrint's last_modified field