A Single cDNA Encodes All Three AedesLeucokinins, Which Stimulate Both Fluid Secretion by the Malpighian Tubules and Hindgut Contractions*
- From the ‡Department of Entomology and Center for Insect Science, The University of Arizona, Tucson, Arizona 85721, the¶Department of Entomology, The University of Georgia, Athens, Georgia 30602, and the **Department of Biomedical Sciences, Creighton University, Omaha, Nebraska 68178
Abstract
A cDNA encoding preproleucokinin was isolated from a cDNA library of the mosquito Aedes aegypti. The deduced amino acid sequence of Aedes preproleucokinin contains a putative signal peptide of 18 amino acid residues and a 210-amino acid residue proleucokinin. Within the proleucokinin are encoded one copy each of the Aedes leucokinins 1, 2, and 3 isolated previously from this species (Veenstra, J. A. (1994)Biochem. Biophys. Res. Commun. 202, 715–719). All threeAedes leucokinins depolarize the transepithelial voltage of the malpighian tubule in concentrations of less than 10−9 m and increase the frequency of hindgut contractions at concentrations above 10−8 m. At higher concentrations the Aedes leucokinins 1 and 3 but notAedes leucokinin 2 are also able to increase the rate of fluid secretion by the malpighian tubules. The differences of the threeAedes leucokinins in their potencies to induce fluid secretion or depolarizations in the malpighian tubules suggest that there may be more than one type of leucokinin receptor in this tissue.
Footnotes
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↵* This work was supported by Grants AI 33108, AI 33429, and DK 49610 from the National Institutes of Health and grants from the John D. and Catherine T. McArthur Foundation.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) U66832.
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↵§ To whom correspondence should be addressed: Laboratoire de Neuroendocrinologie des Insectes, Département de Physiologie des Invertebrés, Université de Bordeaux 1, Avenue des Facultés, 33405 Talence Cedex, France. Fax: 33-5 56 84 87 50; E-mail: veenstra{at}invertebre.u-bordeaux.fr.
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↵‖ Present address: Dept. of Neuroscience, 446 Crawford Hall, University of Pittsburgh, Pittsburgh, PA 15260.
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↵1 The abbreviations used are: CRF, corticotropin-releasing factor; PCR, polymerase chain reaction.
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↵2 D. H. Petzel, unpublished observation.
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- Received October 21, 1996.
- Revision received February 3, 1997.
