Characterization of Effects of G6PC2 Gene Variants on Transcription and Splicing

G6PC2 基因变体对转录和剪接的影响的表征

• 批准号: 7713526
• 负责人: Richard M O'Brien
• 金额: $ 38.18万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7713526
• 关键词: Address; Advocate; Affect; Amino Acids; Animal Model; Blood Glucose; Cardiovascular system; Catalytic Domain; Childhood; Collection; Colorado; Data; Diabetes Mellitus; Disease; Enhancers; Exons; Fasting; Functional RNA; Future; Gene Deletion; Gene Expression; Gene Family; Genes; Genetic; Genetic Transcription; Genetic Variation; Genome; Genomics; Glucokinase; Glucose; Glucose-6-Phosphate; Glycogen Storage Disease; Goals; Human; Hydrolysis; Hypoglycemia; Intercistronic Region; Introns; Islets of Langerhans; Laboratories; Letters; Link; Linkage Disequilibrium; Liver; Mus; Mutation; Names; Non-Insulin-Dependent Diabetes Mellitus; Pathway interactions; Physiological; Predisposition; Proteins; Publishing; RNA Splicing; Reagent; Regulation; Relative (related person); Reporting; Sequence Analysis; Single Nucleotide Polymorphism; Staging; Time; Variant; base; cis acting element; fasting blood glucose level; fusion gene; genome wide association study; glucose metabolism; glucose-6-phosphatase; inorganic phosphate; insulin secretion; islet; knockout animal; mRNA Precursor; member; mortality; mouse genome; promoter; public health relevance; research study

DESCRIPTION (provided by applicant): The glucose-6-phosphatase catalytic subunit gene family comprises three members, G6PC, G6PC2 and G6PC3. G6PC is predominantly expressed in liver where it catalyses the terminal step in the gluconeogenic and glycogenolytic pathways, namely the hydrolysis of glucose-6-phosphate (G6P) to glucose and inorganic phosphate. G6PC2, initially known as IGRP, is ~50% identical at the amino acid level to G6PC but it is expressed specifically in pancreatic islets. G6PC2 also hydrolyses G6P, though at a much lower rate than G6PC. This is consistent with the observation that deletion of the G6PC2 gene in mice results in decreased fasting blood glucose levels, suggesting that G6PC2 normally opposes the action of glucokinase in islets and lowers intracellular G6P concentrations and consequently glucose-stimulated insulin secretion. Two recent genome wide association (GWA) studies have linked single nucleotide polymorphisms (SNPs) in the G6PC2 gene to variations in fasting blood glucose levels in humans, a parameter that is linearly correlated with cardiovascular-associated mortality. Our preliminary data strongly support the hypothesis that sequence variations in the G6PC2 gene, rather than surrounding genes, contribute to elevated fasting blood glucose levels and hence cardiovascular-associated mortality. This project is therefore at a more advanced stage relative to many other GWA studies where disease-associated SNPs have been reported but the disease-associated genes remain to be identified. The goal of the experiments proposed in this application is to extend the GWA studies by functionally characterizing the effects of G6PC2 gene variants on transcription (Aim 1) and splicing (Aim 2). Our initial experiments have shown that two SNPs in the G6PC2 promoter affect G6PC2 fusion gene transcription. In addition, our sequence analyses suggest that the G6PC2 SNP that was first linked to variations in fasting blood glucose is located in a branch point, a key cis-acting element controlling pre-mRNA splicing.

描述(申请人提供)：葡萄糖-6-磷酸酶催化亚基基因家族由G6PC、G6PC2和G6PC3三个成员组成。G6PC主要在肝脏中表达，在肝脏中催化葡萄糖异生和糖原分解途径的最后一步，即葡萄糖-6-磷酸(G6P)水解为葡萄糖和无机磷。G6PC2最初被称为IGRP，在氨基酸水平上与G6PC有50%的同源性，但它在胰岛特异表达。G6PC2也能水解G6P，但速度比G6PC低得多。这与小鼠G6PC2基因缺失导致空腹血糖水平下降的观察结果一致，这表明G6PC2通常与胰岛中葡萄糖激酶的作用相反，并降低细胞内G6P浓度，从而降低葡萄糖刺激的胰岛素分泌。 最近的两项全基因组关联(GWA)研究将G6PC2基因的单核苷酸多态(SNPs)与人类空腹血糖水平的变化联系起来，这一参数与心血管相关死亡率呈线性相关。我们的初步数据有力地支持了这一假设，即G6PC2基因的序列变异，而不是周围的基因，导致空腹血糖水平升高，从而导致心血管相关死亡。因此，与GWA的许多其他研究相比，该项目处于更高级的阶段，在这些研究中，已报告了与疾病相关的SNPs，但与疾病相关的基因仍有待确定。本申请中提出的实验的目标是通过从功能上表征G6PC2基因变体对转录(目标1)和剪接(目标2)的影响来扩展GWA研究。我们的初步实验表明，G6PC2启动子中的两个SNPs影响G6PC2融合基因的转录。此外，我们的序列分析表明，最初与空腹血糖变化有关的G6PC2 SNP位于一个分支点，这是控制前mRNA剪接的关键顺式作用元件。