CHARACTERIZATION OF TYPE 2 DIABETES SUSCEPTIBILITY ALLELES AT THE PKLR LOCUS

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。相当多的证据支持在染色体1q21-q23上存在一些2型糖尿病(T2 DM)易感基因。肝丙酮酸激酶基因(PKLR)附近的变异与T2 DM的关联已在几个高加索人群中复制，但关联区域很广，至少包括6个表达的基因。这项提议将检验这一假设，即该区域的非编码变异会改变一个或多个基因的表达，并导致携带易感单倍型的个体肝脏葡萄糖产量增加。提出了一种多方面的方法，首先使用单核苷酸多态来定义高加索人和非裔美国人的关联区域(目标1)。在这个区域内，将对24名高加索人和24名非裔美国人的所有编码、保守和假定的调节区的变异进行筛查。将寻找改变基因拷贝数的复制和重排的证据(目标2)。AIM 3将测试皮下脂肪、肌肉和永生化淋巴细胞中该区域所有顺应性基因按基因型的表达水平差异，并将测试在转录序列中发现常见变异的等位基因表达差异。目的4将测试10个单倍型纯合子个体，以确定胰岛素分泌、正常血糖钳夹胰岛素敏感性和肝脏葡萄糖产生。将获得脂肪和肌肉，以将该区域基因的表达谱与表型相关联。这些研究可能确定导致T2 DM的特定核苷酸变异，或者确定增加该区域易感性的途径和基因。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Considerable evidence supports the existence of several susceptibility genes for type 2 diabetes (T2DM) on chromosome 1q21-q23. Association of variants near the liver pyruvate kinase gene (PKLR) with T2DM has been replicated in several Caucasian populations, but the region of association is broad and includes at least 6 expressed genes. This proposal will test the hypothesis that noncoding variants in this region alter expression of one or more genes and result in increased hepatic glucose production among individuals carrying the susceptible haplotype. A multifaceted approach is proposed, that will first define the region of association in both Caucasian and African American subjects using single nucleotide polymorphisms (Aim 1). Within this region, variation in all coding, conserved, and putative regulatory regions will be screened for variation in 24 Caucasian and 24 African American individuals. Evidence for duplications and rearrangements altering gene copy number will be sought (Aim 2). Aim 3 will test for differences in expression levels by genotype for all amenable genes in this region in subcutaneous fat, muscle, and immortalized lymphocytes, and will test for differences in allelic expression where common variants in transcribed sequences are found. Aim 4 will test 10 individuals homozygous for each haplotype to determine insulin secretion, insulin sensitivity by euglycemic clamp, and hepatic glucose production. Fat and muscle will be obtained to correlate phenotype with expression profiles of genes in this region. These studies may identify the specific nucleotide variant leading to T2DM, or alternatively will identify the pathway and genes that increase susceptibility in this region.