Fig. 4. Overexpression of XOtx5b or XOtx2 in developing Xenopus retinoblasts causes an increase in photoreceptors or bipolars, respectively. (A) Co-lipofection of GFP and the pCS2⁺ vector in the Xenopus retina. A diversity of retinal cell types express the fluorescent marker. White lines are drawn over the inner and outer plexiform layers to better define the outer nuclear layer (ONL), inner nuclear layer (INL) and the ganglion cell layer (GCL). (B) Retina co-lipofected with XOtx5b and GFP shows an increase in lipofected photoreceptor cells (arrow). The insets show a close-up of a cone (C) and a rod (R) photoreceptor cell. (C) Retina co-lipofected with XOtx2 and GFP shows an increase in the number of lipofected bipolar cells (arrowhead). (Inset) Confocal image of a representative bipolar cell (BP). (D,E) Each of the retinal cell types (GC, ganglion cells; Am, amacrine cells; BP, bipolar cells; Mü, Müller cells; H, horizontal cells; PR, photoreceptor cells) was counted per retina (n) and the percentage for each was determined. The graphs show an average of the percentages obtained. (D) GFP + pCS2⁺ (n=45) and XOtx5b + GFP (n=32) lipofected retinas. (E) GFP + pCS2⁺ (n=20) and XOtx2 + GFP (n=20) lipofected retinas. The error bars represent the s.e.m. The asterisks indicate significant difference by a Student's t-test between the ratios found for the control versus the experimental for that particular cell type with P0.003.

Return to article