FGF2 expression in <i>Tg(RHO P347S)</i> PRs returns to WT levels in the absence of EDN2.

<p>(A) qRT-PCR quantification of <i>Edn2</i>, <i>Gm12541</i>, <i>Fgf2</i> and <i>Gfap</i> expression in <i>Tg(RHO P347S)</i> retinas in the presence or absence of EDN2 function. Bar graphs show the expression of mRNAs in retinas of the indicated genotypes relative to the expression levels seen in <i>Edn2^+/+</i> (WT) retinas. Fold down-regulation in <i>Tg(RHO P347S)</i>; <i>Edn2^−/−</i> retinas vs. <i>Tg(RHO P347S); Edn2^+/+</i> retinas is shown to the right of the vertical bars (n = 3;p<0.05 for all mRNAs). All qRT-PCR values were normalized to <i>Gapdh</i> mRNA. ND (not detected). (B) Immunostaining for FGF2 showed low levels of expression in all three retinal nuclear layers in <i>Edn2^+/+</i> and <i>Edn2^−/−</i> retinas, but FGF2 expression increased significantly in the PRs of <i>Tg(RHO P347S); Edn2^+/+</i> retinas at PN21 (third top panel). In contrast, FGF2 staining was similar to WT retinas in <i>Tg(RHO P347S)</i>; <i>Edn2^−/−</i> retinas and, most notably, from PRs (fourth upper panel). GFAP expression in Müller cells was increased in <i>Tg(RHO P347S); Edn2^+/+</i> retinas (third bottom panel), but reduced in <i>Tg(RHO P347S)</i>; <i>Edn2^−/−</i> retinas (fourth bottom panel). GFAP expression in <i>Tg(RHO P347S)</i>; <i>Edn2^−/−</i> retinas was higher than in <i>Edn2^+/+</i> retinas. ONL, outer nuclear layer; INL, inner nuclear layer; GCL, ganglion cell layer. (Bar = 25 µm). Error bars indicate SEM.