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: A recent study in zebrafish has suggested that at blastula to gastrula stages, BMP signals in the anterior neural ectoderm promote telencephalic identity at the expense of eye-field character (Bielen and Houart, 2012). To examine whether this molecular mechanism also acts in amniotes, we isolated late blastula stage (stage 2) medial (M) explants (Fig. 2A; Patthey et al., 2009) and cultured them alone or in the presence of the BMP inhibitor Noggin for 33 h, by which time intact embryos would correspond to approximately stage 10. Thereafter, the explants were processed and analyzed for marker expression on consecutive sections (Fig. 2A; see Materials and Methods for details).Fig. 2.
Affiliation: Umeå Centre for Molecular Medicine, Umeå University, Umeå 901 87, Sweden.