Abstract
Purpose: :
To investigate the mechanisms by which the retinal pigment epithelium (RPE) plays a role in the development of the retina and to examine whether Nok expression in the RPE participates in this process.
Methods: :
By using a stable and clean transgenic approach, we generated unique transgenic zebrafish embryos in which the RPE but not the neural retina expresses functional Nok. We then used immunohistochemical and genetic approaches to analyze the effects of the restoration of the RPE defects on the development of the retina in the nokm520 mutants.
Results: :
Our study identified a series of previously undocumented developmental steps that are essential for retinal cellular pattern formation: Nok ensures RPE integrity; an intact RPE can sufficiently maintain proper retinal polarity prior to embryonic photoreceptor genesis; RPE-mediated retinal epithelial polarity underlies proper pattern formation of retinal ganglion and inner nuclear cells; and retinal expression of Nok is required for photoreceptor patterning and morphogenesis.
Conclusions: :
Our study not only sheds light on how the nok gene functions in retinal development, but also provides critical insights into how the RPE normally participates in retinal development.
Keywords: retinal development • cell adhesions/cell junctions • retinal pigment epithelium