Sec71 exclusively localizes to TGN in photoreceptors. Immunostaining of retinas dissected from wild-type young and late-pupal flies with (A) anti-p120 (green), anti-GM130 (red) and anti-Sec71 (blue) antibodies; (B) anti-Rab11 (green), a medial-Golgi marker, anti-MPPE (red), and anti-Sec71 (blue) antibodies. Anti-MPPE antibody stains not only the medial Golgi but also the tips of the rhabdomeres. It is not known whether the latter staining represents genuine MPPE localization. (C–G) Left, immunostaining of retinas by the indicated antibodies. GalT::ECFP was expressed in D. Right, plots of signal intensities from images to the left. Signal intensities were measured along the 1.5 µm arrow in the insets; graphs show the overlap between channels. Scale bars: 5 μm (A,B), 1 μm (C–G).