Abstract
Abstract: :
Purpose: Frizzleds are transmembrane receptors that can transduce signals dependent upon binding of Wnts, a large family of secreted glycoproteins critical for a wide variety of normal and pathological developmental processes. In the nervous system, Wnts and Frizzleds play an important role in anterior-posterior patterning, cell fate decisions, proliferation, and synaptogenesis. However, little is known about the role of Frizzled signaling in developing eye. Methods: We isolated cDNAs using degenerate primers for ten chick Frizzleds and analyzed the spatial and temporal expression patterns of Frizzled transcripts during eye development in the chick embryo in whole mount embryos and on cryostat sections. Results: Frizzled (Frz)-1 to -9 are specifically expressed in the eye at early and later stages of development and show a complex and partially overlapping pattern of expression. Frz-4 and Frz-5 are expressed in the neural retina at optic vesicle and optic cup stages. Expression of Frz-1, -2, -4, -5, -6, -7 and -8 is located in the retina at embryonic day (E) 4. Frz-1-4 and Frz-6-9 show a highly dynamic expression pattern at later stages of retinal development. Conclusion: The complex expression pattern suggest that Frizzled receptors play a regulatory role at different stages of eye development in the chick embryo.
Keywords: retinal development • growth factors/growth factor receptors • cell-cell communication