Excretion

An EST project on Aedes aegypti identifies proteins involved in ion transport in the midgut and malpighian tubules

S. S. Gill, L. S. Ross & H. Wadiak

Dept. Cell Biol. & Neuroscience, Univ. California, Riverside, CA 92521

Ion and nutrient transport plays a critical role for the success of mosquitoes in a variety of environments. While some of these transport processes have been physiologically characterized there is very little molecular data on the nature of these proteins and the diversity of these proteins. To identify these proteins we used an expressed sequence tag (EST) approach using cDNA libraries that were generated from the midgut and Malpighian tubules from larval and adult Aedes aegypti. Microbore chromatography was used to size fractionate DNA and enrich for full-length cDNAs. Single pass 5’ sequencing showed many of the clones obtained were full-length clones. The EST sequences identified many of the putative proteins involved in ion and nutrient transport. These include many of the subunits of the V-ATPase pump that generates a potential gradient both in the midgut and Malpighian tubules; the NaKCl cotransporter, which is involved in basolateral membrane transport of Na + , K + and Cl - ; the NaH antiporter, which is thought to be involved in apical transport of Na + ; Cl - channels and a number of transporter-like proteins involved in nutrient transport. Using antibodies developed against these proteins we are presently identifying the distribution of these proteins in mosquito midgut and Malpighian tubules. Data on EST sequences and immunohistochemistry will be presented. (Supported in part from a grant from the US National Institutes of Health).

Index terms: Aedes aegypti, NaKCl, NaH, V-ATPase, transporter.

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