Fig. 4

Mys is expressed in R-cell axons. 3rd-instar larval eye discs were double-stained with anti-HRP (green) and anti-Mys antibodies (magenta). A Wild type, anti-HRP staining visualized R-cell soma and axons. Aʹ The same section stained with anti-Mys antibody. Aʺ The section visualized with both anti-HRP and anti-Mys staining. Mys appeared to be expressed broadly in the eye disc. Strong Mys expression was detected in R-cell axons that migrate from the most posterior end of the eye disc into the optic stalk. B–Bʺ Enlarged view of the boxed area in A–Aʺ. Note the strong Mys staining in R-cell axons. C–Cʺ When mys was knocked down in eye-disc epithelium but not WG by expressing UAS-mys-RNAi-HMS00043 under control of ey^3.5-GAL4, the intensity of Mys staining was greatly reduced in both R-cell soma and accessory cells in the eye disc, confirming that Mys is expressed in both R cells and accessory cells. The staining in R-cell axons was also significantly reduced. D–Dʺ Enlarged view of the boxed area in C–Cʺ. The intensity of Mys staining in R-cell axons was greatly reduced. Note anti-Mys staining at the most posterior region of the eye disc in knockdown animals were mostly associated with sub-retinal glia but not R-cell axons, which is consistent with that expression of UAS-mys-RNAi-HMS00043 under control of ey^3.5-GAL4 knocked down mys in eye-disc epithelium but not sub-retinal glia. Scale bar: 20 µm