Loss of maternal Smad5 in zebrafish embryos affects patterning and morphogenesis of optic primordia
- Hammerschmidt, M., Kramer, C., Nowak, M., Herzog, W., and Wittbrodt, J.
- Developmental dynamics : an official publication of the American Association of Anatomists 227(1): 128-133 (Journal)
- Registered Authors
- Hammerschmidt, Matthias, Herzog, Wiebke, Nowak, Matthias, Wittbrodt, Jochen
- MeSH Terms
- Animals, Genetically Modified
- Body Patterning*
- Bone Morphogenetic Proteins/genetics
- Bone Morphogenetic Proteins/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism*
- Eye/anatomy & histology
- In Situ Hybridization
- Signal Transduction
- Smad5 Protein
- Zebrafish Proteins
- 12701105 Full text @ Dev. Dyn.
Hammerschmidt, M., Kramer, C., Nowak, M., Herzog, W., and Wittbrodt, J. (2003) Loss of maternal Smad5 in zebrafish embryos affects patterning and morphogenesis of optic primordia. Developmental dynamics : an official publication of the American Association of Anatomists. 227(1):128-133.
The mechanisms of patterning and morphogenesis of vertebrate eye primordia are heavily debated. Taking advantage of the maternal effect of a zebrafish smad5 null mutation (Mm169), we investigate the effect of early signaling by members of the bone morphogenetic proteins (Bmps) on eye field patterning and optic vesicle morphogenesis. In contrast to previous Xenopus and chick studies demonstrating a late dorsalizing effect of Bmp4 expressed in the dorsal neural retina itself, we show that patterning of the eye primordia already starts during blastula and early gastrula stages. At these stages, bmps expressed on the ventrolateral side of the embryo promote dorso-distal fates in the entire neuroectoderm, including the eye primordia. Despite a normal split of the eye field in the midline, the eye primordia of Mm169 embryos fail to evaginate laterally. They display a concentric pattern with retinal cells in the center and optic stalk cells in the periphery , representing a flattened version of the topologic relationships present in the mature wild-type eye. Different interpretations of these latter findings are presented. They can be best explained with a model according to which zebrafish eye morphogenesis occurs as a telescopic extension of disc-like, concentric primordia, similar to the development of appendages from imaginal discs in Drosophila.
Genes / Markers
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes