Neural retina identity is specified by lens-derived BMP signals.
Bottom Line: Subsequently, our results provide evidence that a Rax2-positive eye-field state is not sufficient for the progress to a neural retina identity, but requires BMP signals.In addition, our results argue against any essential role of Wnt or FGF signals during the specification of neural retina cells, but provide evidence that Wnt signals together with BMP activity are sufficient to induce cells of retinal pigment epithelial character.We conclude that BMP activity emanating from the lens ectoderm maintains eye-field identity, inhibits telencephalic character and induces neural retina cells.
Affiliation: Umeå Centre for Molecular Medicine, Umeå University, Umeå 901 87, Sweden.Show MeSH
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Mentions: Next, we analyzed whether BMP activity is sufficient to suppress dorsal telencephalic cell identity and induce retinal character by culturing stage 9/10 prospective dorsal telencephalic (dT) explants (Gunhaga et al., 2003) alone or in the presence of BMP4. Stage 9/10 dT explants cultured alone generated FoxG1+ and Emx2+ dorsal telencephalic cells, but no Rax2+ or Vsx2+ neural retina cells or Mitf+ RPE cells (Fig. 6A). In the presence of BMP4, the generation of FoxG1+ and Emx2+ telencephalic cells was completely inhibited in stage 9/10 dT explants, and instead Rax2+ and Vsx2+ neural retina cells were induced, but no Mitf+ RPE cells were detected (Fig. 6B). Thus, BMP activity is sufficient to suppress dorsal telencephalic cell fate and induce Rax2+ and Vsx2+ neural retina cells.Fig. 6.
Affiliation: Umeå Centre for Molecular Medicine, Umeå University, Umeå 901 87, Sweden.