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The rod outer segment (ROS) is attached to the visual cell body by a connecting cilium. Axonemal components of this cilium extend into the ROS, an organelle which undergoes continuous renewal throughout life. New membranous disks are added at the ROS base, while older ones are shed from the tip. The formation of new disks is believed to result from plasma(More)
Actin has been localized in Rana pipiens retinas that were fixed and embedded in aldehyde cross-linked BSA. Thin sections were reacted sequentially with (a) affinity-purified antiactin antibodies induced in rabbits; (b) biotinyl-sheep anti-rabbit antibodies; and (c) avidin-ferritin conjugates. As expected, antiactin labeling density was high in the apical(More)
The connecting (sensory) cilium of rods and cones is the stalk that separates the outer segment, which contains visual pigment in stacks of membrane discs, from the inner segment, which contains cytoplasmic organelles involved in protein synthesis. There are conflicting reports on the occurrence of abnormal motile cilia in patients with retinitis pigmentosa(More)
A new procedure for assaying the phagocytosis of rod outer segments (ROS) by cultured rat pigment epithelial (PE) cells has been developed. Using an ROS antiserum and a double immunofluorescent labeling procedure, ROS attached to the external surfaces of these cells can be distinguished from those that have already been ingested. We have used this procedure(More)
The contractile protein actin was recently localized to the distal portion of the connecting cilium in frog photoreceptors (Chaitin et al J Cell Biol 99:239-247, 1984). This is the site where the ciliary plasma membrane evaginates to form new outer segment disks (Steinberg et al J Comp Neurol 190: 501-518, 1980). In the present study, aldehyde fixed(More)
A 9 + 0 cilium represents the only connection between the light-sensitive rod outer segment (ROS) and the visual cell body. Differentiation of a ROS derives from a remodeling of the plasma membrane at the distal end of the cilium. Prior to this event, an actin-rich domain can be demonstrated within the distal cilium using immunocytochemical techniques. This(More)
The distribution of the cell surface adhesion/receptor molecule CD44 was studied in retinas of the Royal College of Surgeons (RCS) rat which exhibits an inherited retinal dystrophy. In this animal model, the retinal pigment epithelium fails to phagocytize shed photoreceptor outer segment material, a membranous debris layer accumulates in the subretinal(More)
The photoreceptor outer segment (OS) develops from the distal end of a nonmotile cilium and exhibits a continuous renewal of its disc structures throughout life. Immunocytochemical studies have localized an actin-rich domain to the ciliary axoneme at the base of the OS, and recent ultrastructural studies of detergent-extracted retinas have demonstrated(More)
In adult mouse retinas the standard form of the cell surface adhesion/receptor molecule CD44 is localized to Müller cell apical microvilli. In the rds (retinal degeneration slow) mouse, however, CD44 immunolabel is increased and distributed throughout the retina by 3 months postnatal. At present, it is unclear if this labeling pattern is due to the(More)