STRUCTURAL ANALYSIS OF CANDIDATE GENES FOR TYPE 2 DIABETES

一个基因被认为是Pimas 2型糖尿病的候选基因，如果1）它与另一个人群中的糖尿病表型相关，或2）它具有生理相关功能，并位于与糖尿病相关的染色体区域。迄今为止已分析的候选基因包括那些在其他人群中与Mody相关的基因。我们在HNFla、HNFlb和HNF3b基因中发现了几种多态性，但没有一种与Pimas的早发性糖尿病相关。然而，HNFlb中的一种多态性预测了蛋白质的DNA结合区域内的非保守氨基酸取代。因此，研究了HNF 1b中的取代的功能变异性。我们已经将HNF 1b的两种多态性形式克隆到表达载体中。此外，我们已经克隆了大鼠白蛋白启动子，这是由HNF 1b调控，到荧光素酶报告质粒。将含有HNF1b的每个载体与荧光素酶报告质粒共转染到Cos 7细胞中。我们已经发现，不常见的氨基酸变异上调转录从大鼠白蛋白promoter.We还分析了多态性的候选基因被认为是负责糖尿病位点NIDDM1在墨西哥裔美国人。我们对1300名皮马印第安人的这种多态性进行了基因分型，并发现非糖尿病皮马人的胰岛素抵抗和营养分配与此相关。我们还对15号染色体上的一个相关基因附近的第二个多态性进行了基因分型，该基因被认为与墨西哥裔美国人的NIDDM1基因座相互作用。我们没有发现任何显着的协会与15号染色体上的多态性在Pimas。- 人类受试者

A gene is considered a candidate gene for type 2 diabetes in Pimas if 1) it is associated with a diabetic phenotype in another population or 2) it has a physiologically relevant function and is positioned in a chromosomal region that is linked to diabetes. Candidate genes which have been analyzed to date include those genes which are associated with Mody in other populations. We identified several polymorphisms in the HNFla, HNFlb, and HNF3b genes, but none were associated with early onset diabetes in Pimas. One polymorphism in HNFlb, however, predicts a non-conservative amino acid substitution within the DNA binding region of the protein. Therefore the substitution in HNF1b was investigated for functional variability. We have cloned the two polymorphic forms of HNF1b into expression vectors. In addition, we have cloned the rat albumin promoter, which is regulated by HNF1b, into a luciferase reporter plasmid. Each of the vectors containing HNF1b were co- transfected with the luciferase reporter plasmid into Cos 7 cells. We have found that the uncommon amino acid variant upregulates transcription from the rat albumin promoter.We have also analyzed a polymorphism in a candidate gene which is thought to be responsible for the diabetic locus NIDDM1 in Mexican Americans. We have genotyped this polymophism in 1300 Pima Indians and have found an association with insulin resistance and nutrient partitioning in non-diabetic Pimas. We have also genotyped a second polymorphism near a related gene on chromosome 15 which is thought to interact with the NIDDM1 locus in Mexican Americans. We did not find any significant associations with the polymorphism on chromosome 15 in Pimas. - Human Subjects