Fasciola gigantica: Molecular Analysis of a Water Channel Protein (Aquaporin)

Abstract

Fasciolosis caused by Fasciola gigantica is an important disease of cattle in Thailand.
In order to develop new drugs and vaccines we have recently started to conduct research on
aquaporins in Fasciola. Aquaporins (AQPs) are essential for the maintenance of water
homeostasis in all organisms including animals, plants, and bacteria. Structure, function, and
pathology of AQPs have been extensively studied in vertebrates but data for AQPs of
trematodes is still limited. In the present study, a cDNA encoding an aquaporin (FgAQP-1)
was molecular cloned from a metacercarial stage cDNA library of F. gigantica. The FgAQP-
1 cDNA contained the complete coding sequence for a protein of 299 amino acid residues.
Comparison of the deduced amino acid sequence with protein sequences in public databases
using NCBI-BLASTP showed highest similarity to aquaporin-1 of Bos taurus. Expression
and distribution of FgAQP-1 has been characterized at the nucleic acid and protein level in
the adult parasite. Functional data of FgAQP-1 will be obtained after transformation of yeast
with a plasmid carrying FgAQP-1 DNA by stopped flow analysis. Furthermore, it is planned
to introduce mutations into the original FgAQP-1 sequence to analyze the importance of
single amino acid residues for the functional integrity of the protein.