Targeting of an expressed neurotoxin by its recombinant baculovirus
Author:
Elazar Menashe1, Levi Rafi1, Zlotkin Eliahu1
Affiliation:
1. Department of Animal and Cell Biology, The Life Science Institute, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
Abstract
SUMMARYAaIT, an insect-selective neurotoxic polypeptide derived from scorpion venom, has recently been used to engineer recombinant baculoviruses for insect pest control. Lepidopterous larvae infected with an AaIT-expressing baculovirus reveal symptoms of paralysis identical to those induced by injection of the native toxin. However, the paralyzed larvae treated by the recombinant virus possess an approximately 50-fold lower hemolymph toxin concentration than insects paralyzed by the native toxin. The mechanism of this potentiation effect was studied using immunocytochemistry, electrophysiology and toxicity assays. (i) Light microscopy, using peroxidase-conjugated antibodies, revealed the presence of toxin in virus-susceptible tissues, including tracheal epithelia located close to the central nervous system and beyond its lamellar enveloping sheath. (ii) High-resolution immunogold electron microscopical cytochemistry clearly revealed the presence of recombinant AaIT toxin inside the thoracic and abdominal ganglia on neuronal cell bodies and axonal membranes. (iii) Ventral nerve cords dissected from silkworm larvae infected with the recombinant baculovirus exhibited a high degree of excitability, expressed as enhanced frequency and bursting mode of their spontaneous activity, when compared to nerve cords infected with the wild-type virus. We conclude that the recombinant-virus-infected tracheal epithelia, outbranching in the body of an infected insect, (i) locally supply a continuous, freshly produced toxin to its neuronal receptors and (ii) introduce the expressed toxin to the insect central nervous system, thus providing it with critical target sites that are inaccessible to the native toxin.
Publisher
The Company of Biologists
Subject
Insect Science,Molecular Biology,Animal Science and Zoology,Aquatic Science,Physiology,Ecology, Evolution, Behavior and Systematics
Reference35 articles.
1. Barrett, J. W., Brownwright, A. J., Primavera, M. J. and Palli, S. R. (1998). Studies of the nucleopolyhedrosis infection process in insect by using the green fluorescence protein as a reporter. J. Virol.72, 3377–3382. 2. Castel, M., Belenky, M., Cohen, S., Otterson, O. P. and Storm-Mathisen, J. (1993). Glutamate-like immunoreactivity in retinal terminals of the mouse suprachiasmatic nucleus. Eur. J. Neurosci.5, 368–381. 3. Cory, J. S., Hirst, M. L., Williams, T., Halls, R. S., Gouso, D., Carty, T. M., Possee, R. D., Cayley, P. J. and Bishop, D. H. L. (1994). Field trial of genetically improved baculovirus insecticide. Nature370, 138–140. 4. D’Ajello, V., Zlotkin, E., Miranda, F., Lissitzky, S. and Bettini, S. (1972). The effect of scorpion venom and pure toxins on the cockroach central nervous system. Toxicon10, 399–404. 5. Darbon, H., Zlotkin, E., Kopeyan, C., van Rietschoten, J. and Rochat, H. (1982). Covalent structure of the insect toxin of the North African scorpion Androctonus australis Hector. Int. J. Pept. Protein Res.20, 320–330.
Cited by
12 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|