Fig. 1
BMP signaling regulates initiation of dorso-ventral retina patterning. To examine the roles of extra cellular signaling pathways in initiating dorsal retina identity, we carried out in situ hybridization for dorsal (tbx5a, bambia) and ventral (vax2) retina markers in 15 hours post fertilization (hpf) embryos. To block Wnt signaling, we utilized a heat shock inducible Wnt inhibitor Dickkopf 1b (Dkk1b). In parallel, we blocked BMP signaling by injecting embryos with morpholinos targeting growth differentiation factor 6a (gdf6a MO). Dorsal retina genes tbx5a (A-C), and bambia (G-I) are significantly reduced in the absence of BMP but not Wnt signaling. The ventral retina gene vax2 (D-F) is also unaffected by the absence of Wnt signaling, while slightly expanded in embryos lacking BMP signaling. All embryos are shown in dorsal mount with anterior aligned to the left.
Reprinted from Developmental Biology, 388(2), Holly, V.L., Widen, S.A., Famulski, J.K., and Waskiewicz, A.J., Sfrp1a and Sfrp5 function as positive regulators of Wnt and BMP signaling during early retinal development, 192-204, Copyright (2014) with permission from Elsevier. Full text @ Dev. Biol.