CHARACTERIZATION OF CANINE ROD PHOTORECEPTOR CGMP-GATED CATION CHANNEL ALPHA-SUBUNIT GENE AND EXCLUSION OF ITS INVOLVEMENT IN THE HEREDITARY RETINAL DYSTROPHY OF SWEDISH BRIARDS

The nucleotide sequence of the canine rod photoreceptor cGMP-gated cat ion channel alpha-subunit (cCNCGI) cDNA has been determined. The open reading frame consists of 2073 nucleotides, which encode a putative pr otein of 691 amino acids. In addition, we have established the exon/in tron boundaries of the cCNCGI gene and determined the complete sequenc e of six introns of a total of eight. The exon/intron organization (lo cation and length of exons and introns) of the cCNCGI gene is very sim ilar to that of the human rod photoreceptor cGMP-gated cation channel cr-subunit gene. We used single-strand conformation polymorphism analy sis to search for potential pathogenic sequence changes in the cCNCGI gene in a Swedish Briard and Briard-Beagle dog kindred, in which an au tosomal recessive retinal dystrophy is segregating, a disease which sh ows phenotypic similarities to retinitis pigmentosa, a heterogeneous g roup of hereditary and progressive retinal degeneration in human. In i ntron 3, we found several DNA polymorphisms, which do not cosegregate with the affected status of the dogs, thus excluding cCNCGI as a candi date gene for the retinal dystrophy in this strain of Swedish Briards. (C) 1997 Elsevier Science B.V.