Null mutation in shaking-B eliminates electrical but not chemical synapses in the Drosophila giant fibre system: a structural study.

Blagburn, J M, Alexopoulos, H, Davies, J M and Bacon, J F (1999) Null mutation in shaking-B eliminates electrical but not chemical synapses in the Drosophila giant fibre system: a structural study. Journal of Comparitive Neurology, 404 (4). pp. 449-458. ISSN 0021-9967

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Abstract

Mutations in the Drosophila shaking-B gene perturb synaptic transmission and dye coupling in the giant fiber escape system. The GAL4 upstream activation sequence system was used to express a neuronal-synaptobrevin-green fluorescent protein (nsyb-GFP) construct in the giant fibers (GFs); nsyb-GFP was localized where the GFs contact the peripherally synapsing interneurons (PSIs) and the tergotrochanteral motorneurons (TTMns). Antibody to Shaking-B protein stained plaquelike structures in the same regions of the GFs, although not all plaques colocalized with nsyb-GFP. Electron microscopy showed that the GF-TTMn and GF-PSI contacts contained many chemical synaptic release sites. These sites were interposed with extensive regions of close membrane apposition (3.25 nm ± 0.12 separation), with faint cross striations and a single-layered array of 41-nm vesicles on the GF side of the apposition. These contacts appeared similar to rectifying electrical synapses in the crayfish and were eliminated in shaking-B2 mutants. At mutant GF-TTMn and GF-PSI contacts, chemical synapses and small regions of close membrane apposition, more similar to vertebrate gap junctions, were not affected. Gap junctions with more vertebratelike separation of membranes (1.41 nm ± 0.08) were abundant between peripheral perineurial glial processes; these were unaffected in the mutants. J. Comp. Neurol. 404:449¿458, 1999. © 1999 Wiley-Liss, Inc.

Item Type: Article
Schools and Departments: School of Life Sciences > Evolution, Behaviour and Environment
Depositing User: Jane Davies
Date Deposited: 06 Feb 2012 19:03
Last Modified: 20 Mar 2012 13:56
URI: http://sro.sussex.ac.uk/id/eprint/19178
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