an in vivo cis-regulatory screen at the type 2 diabetes associated tcf7l2 locus identifies multiple tissue-specific enhancers一个体内2型糖尿病相关基因工程屏幕tcf7l2轨迹识别多个组织增强剂.pdfVIP

An in vivo cis-Regulatory Screen at the Type 2 Diabetes Associated TCF7L2 Locus Identifies Multiple Tissue- Specific Enhancers 1 1,2 1 Daniel Savic *, Graeme I. Bell , Marcelo A. Nobrega * 1 Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America, 2 Department of Medicine, University of Chicago, Chicago, Illinois, United States of America Abstract Genome-wide association studies (GWAS) have repeatedly shown an association between non-coding variants in the TCF7L2 locus and risk for type 2 diabetes (T2D), implicating a role for cis-regulatory variation within this locus in disease etiology. Supporting this hypothesis, we previously localized complex regulatory activity to the TCF7L2 T2D-associated interval using an in vivo bacterial artificial chromosome (BAC) enhancer-trapping reporter strategy. To follow-up on this broad initial survey of the TCF7L2 regulatory landscape, we performed a fine-mapping enhancer scan using in vivo mouse transgenic reporter assays. We functionally interrogated approximately 50% of the sequences within the T2D-associated interval, utilizing sequence conservation within this 92-kb interval to determine the regulatory potential of all evolutionary conserved sequences that exhibited conservation to the non-eutherian mammal opossum. Included in this study was a detailed functional interrogation of sequences spanning both protective and risk alleles of single nucleotide polymorphism (SNP) rs7903146, which has exhibited allele-specific enhancer function in pancreatic beta cells. Using these assays, we identified nine segments regulating various aspects of the TCF7L2 expression profile and that constitute nearly 70% of the sequences t