title: The synaptic vesicle-associated G protein o-rab3 is expressed in subpopulations of neurons.
abstract: The distribution of o-rab3--a synaptic vesicle-associated low-molecular-weight GTP-binding protein--was studied in various neural tissues of the electric ray Torpedo marmorata. o-rab3 was shown to be associated selectively with isolated cholinergic synaptic vesicles derived from the electric organ. Gel filtration of cholinergic synaptic vesicles using Sephacryl S-1000 column chromatography demonstrated a copurification of o-rab3 with the synaptic vesicle content marker ATP and with SV2--a synaptic vesicle transmembrane glycoprotein. Indirect immunofluorescence using antibodies against o-rab3 and SV2 and a double labeling protocol revealed an identical distribution of both antigens in the cholinergic nerve terminals within the electric organ and at neuromuscular junctions. An immunoelectron microscopic analysis demonstrated the presence of o-rab3 at the surface of the synaptic vesicle membrane. In the CNS immunofluorescence of o-rab3 and SV2 overlap only in small and distinct areas. Whereas SV2 has an overall only in small and distinct areas. Whereas SV2 has an overall distribution in nerve terminals of the entire CNS, o-rab3 is restricted to a subpopulation of nerve terminals in the dorsolateral neuropile of the rhombencephalon and in the dorsal horn of the spinal cord. Our results demonstrate that the synaptic vesicle-associated G protein o-rab3 is specifically expressed only in subpopulations of neurons in the Torpedo CNS.
authors.affiliation: AK Neurochemie, Zoologisches Institut, J. W. Goethe-Universität, Frankfurt am Main, F.R.G.
authors.forename: W
authors.initials: W
authors.lastname: Volknandt
authors.forename: A
authors.initials: A
authors.lastname: Hausinger
authors.forename: B
authors.initials: B
authors.lastname: Wittich
authors.forename: H
authors.initials: H
authors.lastname: Zimmermann
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D029941:Fish Proteins; D005455:Fluorescent Antibody Technique; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D010275:Parasympathetic Nervous System / Q000378:metabolism / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000378:metabolism*; D014101:Torpedo
chemical_list: D029941:Fish Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; C079825:o-rab3 protein, Torpedo marmorata; D019204:GTP-Binding Proteins