title: Relevance of sodium/glucose cotransporter-1 (SGLT1) to diabetes mellitus and obesity in dogs.
abstract: Glucose transport across the enterocyte brush border membrane by sodium/glucose cotransporter-1 (SGLT1, coded by Slc5a1) is the rate-limiting step for intestinal glucose transport. The relevance of SGLT1 expression in predisposition to diabetes mellitus and to obesity was investigated in dogs. Cultured Caco-2/TC7 cells were shown to express SGLT1 in vitro. A 2-kbp fragment of the Slc5a1 5' flanking region was cloned from canine genomic DNA, ligated into reporter gene plasmids, and shown to drive reporter gene expression in these cells above control (P < 0.001). To determine the effect of the 3 known SNPs in this region on promoter function, new promoter/reporter constructs (all permutations of these 3 SNPs) were created by site-directed mutagenesis. No significant differences in promoter function were seen, suggesting that these SNPs do not have a significant effect on the constitutive transcription of SGLT1 mRNA in dogs. A search for novel SNPs in this region in dogs was made in 2 breeds predisposed to diabetes mellitus (Samoyed and cairn terrier), 2 breeds that rarely develop diabetes (boxer and German shepherd), and 2 breeds predisposed to obesity (Labrador retriever and cocker spaniel). The Slc5a1 5' flanking region was amplified from 10 healthy individuals of each of these breeds by high-fidelity PCR with the use of breed-labeled primers and sequenced by pyrosequencing. The sequence of the Slc5a1 5' flanking region in all individuals of all breeds tested was identical. On this evidence, variations in Slc5a1 promoter sequence between dogs do not influence the pathogenesis of diabetes mellitus or obesity in these breeds.
authors: Epithelial Function and Development Group, Department of Functional and Comparative Genomics, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZJ, UK. danb@liv.ac.uk
authors: D J
authors: DJ
authors: Batchelor
authors: A J
authors: AJ
authors: German
authors: S P
authors: SP
authors: Shirazi-Beechey
mesh_terms: D000818:Animals; D001692:Biological Transport; D018938:Caco-2 Cells; D003001:Cloning, Molecular; D003920:Diabetes Mellitus / Q000235:genetics / Q000378:metabolism / Q000662:veterinary*; D004283:Dog Diseases / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D020022:Genetic Predisposition to Disease; D006801:Humans; D016297:Mutagenesis, Site-Directed / Q000662:veterinary; D009765:Obesity / Q000235:genetics / Q000378:metabolism / Q000662:veterinary*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D051269:Sodium-Glucose Transporter 1 / Q000235:genetics / Q000378:metabolism*; D014162:Transfection / Q000662:veterinary
chemical_list: D051269:Sodium-Glucose Transporter 1