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The Synaptic Vesicle‐Associated G Protein o‐rab3 Is Expressed in Subpopulations of Neurons
Author(s) -
Volknandt Walter,
Hausinger Angela,
Wittich Beate,
Zimmermann Herbert
Publication year - 1993
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1993.tb03229.x
Subject(s) - synaptic vesicle , torpedo , vesicle , cholinergic , biology , neuromuscular junction , immunofluorescence , microbiology and biotechnology , neuroscience , biochemistry , immunology , antibody , acetylcholine receptor , membrane , receptor
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 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.