Ultrastructural analysis of vesicular structures expressing HRP-rhodopsin. Morphological characterization of rhodopsin-laden vesicles and tubules of HRP-rhodopsin transfected rods (A–G). Representative longitudinal (A–C, E) and cross-sectional (D, F, G) views of rods are shown. (B) Enlarged view of the boxed area in (A). Curved black arrows point to DAB-labeled vesicle clusters. Black arrows represent DAB-positive vesicles; black arrowheads represent DAB-negative vesicles; white arrows represent DAB-positive tubules; white arrowheads point to the DAB-negative tubules. For simplicity, not all examples are labeled by arrows or arrowheads. Ap appendage; bb basal body; IS inner segment. Scale bars in nm.