Molecular characterization of exon region of type 2 diabetes associated gene (KCNJ11) in Labrador retriever dogs

The study was undertaken with the objective of characterization of the single exon region of potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11) gene in Labrador retriever breeds of dogs. The gene encodes the islet ATP-sensitive potassium channel Kir6.2 which plays a major role in insulin secretion and is of substantial interest as a candidate gene for type 2 diabetes. The genomic DNA was isolated from six pedigreed Labrador retriever breeds of dogs and a 1173 bp fragment of the coding region of KCNJ11 gene was amplified by PCR technique using synthetic oligonucleotide primer pairs and the confirmation of PCR product was done by agarose gel electrophoresis. The PCR amplified products were purified and sequenced commercially. The sequenced data was compared with nucleotide sequences available in the data bank using suitable software. The nucleotide sequence showed 99 per cent homology between Labrador and Boxer breeds of dogs with two bases found to be replaced among the two sequences whereas, 100 per cent homology was observed between sequences of Labrador, Basenji and Great Dane dogs. Predicted amino acid sequence and the secondary protein structure revealed no characteristic change between the dog breeds suggestive of the highly conserved nature of the gene studied. The study can be extended in larger dog population to find out any polymorphism in the respective gene studied which might serve as a breed specific marker for screening diabetic dog population in future.

Keywords: Diabetes mellitus, Labrador retriever, KCNJ11 gene, kir 6.2 subunits, ATP-sensitive potassium channel