IDENTIFICATION OF THE SITE OF MUTATION WITHIN THE M2 REGION OF THE GABA RECEPTOR OF THE CYCLODIENE-RESISTANT GERMAN-COCKROACH

The DNA and amino acid sequences of the membrane-spanning region of th e GABA receptors of the German cockroach have been identified along wi th information on the nature and the specific site of mutation in the cyclodiene-resistant strains. In this resistant strain, the mutation h as occurred at the most conserved, lower M2 cylinder region involving a G to T conversion, resulting in an amino acid change of alanine (GCC ) residue to serine (TCC). The site, furthermore, coincides with the m ost conserved region of all GABA receptor subunits and the expected Cl - transporting segment constituting the innermost surface of the chann el opening, The deduced sequence of the German cockroach GABA receptor differs from that of Drosophila mainly in the connecting region betwe en M3 and M4.