Cloning of a putative inhibitory amino acid receptor subunit from the parasitic nematode Haemonchus contortus

A cDNA, HGl, encoding an inhibitory amino-acid receptor subunit has been cloned from a mixed egg population of the parasitic nematode Haemonchus contortus. The predicted amino-acid sequence of the subunit shows 24% to 32% homology with other vertebrate and invertebrate GABAA and glycine receptor subunits and has all the expected motifs for a member of the ligand-gated ion channel superfamily. When expressed in Xenopus oocytes HGl gives a small response to 1 mM glycine, but not to 1 mM GABA, glutamate, taurine or L-alanine.