Differential expression of neuronal calcium sensor-1 in the developing chick retina.
Neuronal calcium sensor-1 (NCS-1) is a Ca(2+) binding protein that has been implicated in the regulation of neurotransmission and synaptogenesis. In this study we investigated the developmental expression and localization of NCS-1 in the chick retina. Single- and double-labeling experiments with three-dimensional reconstruction as well as ultrastructural data of the distribution of NCS-1 suggest that this protein is also involved in axonal process outgrowth. We found an early expression of NCS-1 in ganglion cells and their axons, in amacrine, and in horizontal cells, whereas photoreceptors were immunonegative at embryonic stages. In the early posthatching days we found strong immunostaining for NCS-1 in horizontal cells and their processes in the outer plexiform layer. In contrast, synaptic vesicle protein 2 (SV2) was prominent only in photoreceptor synaptic terminals. Ultrastructural analysis confirmed that NCS-1 was localized postsynaptically in horizontal cell processes, whereas presynaptic terminals were immunonegative. However, at late posthatching days we observed that photoreceptor ribbon synapses (from rods and/or cones) also expressed NCS-1. Thus the results support the notion that NCS-1 is involved in neuronal process outgrowth and is localized in pre- and postsynaptic compartments including mature photoreceptor synapses.
Department of Medicine, Division of Anatomy, University of Fribourg, rte. A. Gockel 1, CH-1700 Fribourg, Switzerland. mathias.bergmann@unifr.ch
Mathias
M
Bergmann
Detlev
D
Grabs
John
J
Roder
Günter
G
Rager
Andreas
A
Jeromin
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001369:Axons / Q000378:metabolism; D001921:Brain / Q000196:embryology / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002642:Chick Embryo / Q000378:metabolism*; D002645:Chickens / Q000378:metabolism*; D009412:Nerve Fibers / Q000378:metabolism; D051580:Neuronal Calcium-Sensor Proteins; D009479:Neuropeptides / Q000378:metabolism*; D009900:Optic Nerve / Q000196:embryology / Q000378:metabolism; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology; D012160:Retina / Q000196:embryology* / Q000378:metabolism*; D012165:Retinal Ganglion Cells / Q000378:metabolism; D013569:Synapses / Q000378:metabolism
D002135:Calcium-Binding Proteins; D051580:Neuronal Calcium-Sensor Proteins; D009479:Neuropeptides; C101464:frequenin calcium sensor proteins