RESUMO
Recent genome-wide association studies (GWASs) have identified a locus on chromosome 1p13 strongly associated with both plasma low-density lipoprotein cholesterol (LDL-C) and myocardial infarction (MI) in humans. Here we show through a series of studies in human cohorts and human-derived hepatocytes that a common noncoding polymorphism at the 1p13 locus, rs12740374, creates a C/EBP (CCAAT/enhancer binding protein) transcription factor binding site and alters the hepatic expression of the SORT1 gene. With small interfering RNA (siRNA) knockdown and viral overexpression in mouse liver, we demonstrate that Sort1 alters plasma LDL-C and very low-density lipoprotein (VLDL) particle levels by modulating hepatic VLDL secretion. Thus, we provide functional evidence for a novel regulatory pathway for lipoprotein metabolism and suggest that modulation of this pathway may alter risk for MI in humans. We also demonstrate that common noncoding DNA variants identified by GWASs can directly contribute to clinical phenotypes.
Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , LDL-Colesterol/metabolismo , Cromossomos Humanos Par 1/genética , Predisposição Genética para Doença/genética , Polimorfismo de Nucleotídeo Único/genética , Proteínas Adaptadoras de Transporte Vesicular/biossíntese , Proteínas Adaptadoras de Transporte Vesicular/deficiência , Proteínas Adaptadoras de Transporte Vesicular/genética , Animais , Sequência de Bases , Sítios de Ligação , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Células Cultivadas , LDL-Colesterol/sangue , Estudos de Coortes , Doença da Artéria Coronariana/sangue , Doença da Artéria Coronariana/genética , Europa (Continente)/etnologia , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Estudo de Associação Genômica Ampla , Haplótipos/genética , Hepatócitos/metabolismo , Humanos , Lipídeos/sangue , Lipoproteínas VLDL/sangue , Lipoproteínas VLDL/metabolismo , Fígado/citologia , Fígado/metabolismo , Camundongos , Infarto do Miocárdio/sangue , Infarto do Miocárdio/genética , Fenótipo , Transcrição GênicaRESUMO
We combined Gal4-UAS and the FLP recombinase-FRT and fluorescent reporters to generate cell clones that provide spatial, temporal and genetic information about the origins of individual cells in Drosophila melanogaster. We named this combination the Gal4 technique for real-time and clonal expression (G-TRACE). The approach should allow for screening and the identification of real-time and lineage-traced expression patterns on a genomic scale.
Assuntos
Linhagem da Célula , DNA Nucleotidiltransferases/genética , Proteínas de Ligação a DNA/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Técnicas Genéticas , Proteínas de Saccharomyces cerevisiae/genética , Fatores de Transcrição/genética , Animais , Células Clonais , Drosophila melanogaster/citologia , Drosophila melanogaster/embriologia , Fluorometria , Genes Reporter , Proteínas de Fluorescência Verde/genética , Fases de Leitura AbertaRESUMO
A variety of genetic techniques have been devised to determine cell lineage relationships during tissue development. Some of these systems monitor cell lineages spatially and/or temporally without regard to gene expression by the cells, whereas others correlate gene expression with the lineage under study. The GAL4 Technique for Real-time and Clonal Expression (G-TRACE) system allows for rapid, fluorescent protein-based visualization of both current and past GAL4 expression patterns and is therefore amenable to genome-wide expression-based lineage screens. Here we describe the results from such a screen, performed by undergraduate students of the University of California, Los Angeles (UCLA) Undergraduate Research Consortium for Functional Genomics (URCFG) and high school summer scholars as part of a discovery-based education program. The results of the screen, which reveal novel expression-based lineage patterns within the brain, the imaginal disc epithelia, and the hematopoietic lymph gland, have been compiled into the G-TRACE Expression Database (GED), an online resource for use by the Drosophila research community. The impact of this discovery-based research experience on student learning gains was assessed independently and shown to be greater than that of similar programs conducted elsewhere. Furthermore, students participating in the URCFG showed considerably higher STEM retention rates than UCLA STEM students that did not participate in the URCFG, as well as STEM students nationwide.