Vesicular transport of newly synthesized opsin from the Golgi apparatus toward the rod outer segment. Ultrastructural immunocytochemical and autoradiographic evidence in Xenopus retinas.

摘要: Each day, rod photoreceptors of the vertebrate retina synthesize rhodopsin and insert it into new membranes outer segment (ROS). The authors determined which components cell transport opsin from Golgi to ROS by a combined EM autoradiographic immunocytochemical study using radiolabeled amino acid precursors antiopsin antibodies. Radiolabeled proteins in ellipsoid region Xenopus laevis retinal rods were localized comparison distribution silver grains with predicted generated hypothetical source: grain matrix. Sources decay not uniformly distributed. Small vesicles compressed between mitochondria clustered beneath connecting cilium that joins inner contained more than 30% radiolabel had specific activity 17 times higher surrounding cytoplasm. Opsin was immunocytochemically on thin sections retinas embedded Lowicryl K4M (Polysciences; Warrington, PA) reaction sequentially biotinyl-rabbit antifrog opsin, biotinyl-sheep antirabbit F(ab')2, avidin-ferritin. apparatus, intermitochondrial vesicles, prominently labeled. Subellipsoid smooth endoplasmic reticulum labeled at background levels. These results demonstrate intracellular vesicular newly synthesized base X. retinas. Antibody plasma membrane 10-fold greater density contiguous membrane. polarized apparently involves only vectorial but also restrictions randomization inserted