Immunoperoxidase localization of photoreceptor and Müller cell markers in the rosettes: A) The majority of cells comprising the central zone of the rosettes were positive for rod opsin. Cells in the peripheral zone were negative (asterisk). B) interphotoreceptor retinoid-binding protein (IRBP), which is normally secreted by photoreceptors, was restricted to the peripheral lumen of the rosette inside of the external-limiting membrane (arrow). C) Occasional cells showed Müller cell differentiation expressing cellular retinaldehyde-binding protein (CRALBP) positive radial processes that abruptly end at the external limiting membrane. Sections treated with non-immune serum showed no immunospecific reactivity (data not illustrated). Arrows in each panel indicate the position of the external-limiting membrane.