Project description:We used expression quantitative trait locus mapping in the laboratory rat (Rattus norvegicus) to gain a broad perspective of gene regulation in the mammalian eye and to identify genetic variation relevant to human eye disease. Of >31,000 gene probes represented on an Affymetrix expression microarray, 18,976 exhibited sufficient signal for reliable analysis and at least 2-fold variation in expression among 120 F2 rats generated from an SR/JrHsd x SHRSP intercross. Genome-wide linkage analysis with 399 genetic markers revealed significant linkage with at least one marker for 1,300 probes (alpha = 0.001; estimated empirical false discovery rate = 2%). Both contiguous and noncontiguous loci were found to be important in regulating mammalian eye gene expression. We investigated one locus of each type in greater detail and identified putative transcription-altering variations in both cases. We found an inserted cREL binding sequence in the 5' flanking sequence of the Abca4 gene associated with an increased expression level of that gene, and we found a mutation of the gene encoding thyroid hormone receptor beta 2 associated with a decreased expression level of the gene encoding short-wave sensitive opsin (Opn1sw). In addition to these positional studies, we performed a pairwise analysis of gene expression to identify genes that are regulated in a coordinated manner and used this approach to validate two previously undescribed genes involved in the human disease Bardet-Biedl syndrome. These data and analytic approaches can be used to facilitate the discovery of additional genes and regulatory elements involved in human eye disease. Experiment Overall Design: mRNA from whole eye tissue was used to assay gene expression level. Samples were acquired from 120 F2 rats generated from an SR/JrHsd x SHRSP intercross. Each sample was run individually, according to standard Affymetrix protocols, without replicates.
Project description:We used expression quantitative trait locus mapping in the laboratory rat (Rattus norvegicus) to gain a broad perspective of gene regulation in the mammalian eye and to identify genetic variation relevant to human eye disease. Of >31,000 gene probes represented on an Affymetrix expression microarray, 18,976 exhibited sufficient signal for reliable analysis and at least 2-fold variation in expression among 120 F2 rats generated from an SR/JrHsd x SHRSP intercross. Genome-wide linkage analysis with 399 genetic markers revealed significant linkage with at least one marker for 1,300 probes (alpha = 0.001; estimated empirical false discovery rate = 2%). Both contiguous and noncontiguous loci were found to be important in regulating mammalian eye gene expression. We investigated one locus of each type in greater detail and identified putative transcription-altering variations in both cases. We found an inserted cREL binding sequence in the 5' flanking sequence of the Abca4 gene associated with an increased expression level of that gene, and we found a mutation of the gene encoding thyroid hormone receptor beta 2 associated with a decreased expression level of the gene encoding short-wave sensitive opsin (Opn1sw). In addition to these positional studies, we performed a pairwise analysis of gene expression to identify genes that are regulated in a coordinated manner and used this approach to validate two previously undescribed genes involved in the human disease Bardet-Biedl syndrome. These data and analytic approaches can be used to facilitate the discovery of additional genes and regulatory elements involved in human eye disease. Keywords: eQTL, F2 cross
Project description:to understand the consequences of chronic exposure to fluoxetine during postnatal life on global transcriptional changes withing the rat hippocamps Agilent one-color experiment,Organism: Rattus Norvegicus, Agilent-016352 Genotypic designed Custom Rattus Norvegicus 8x15k, Labeling kit: Agilent Quick-Amp labeling Kit (p/n5190-0442)
Project description:We report RNA-Seq experiments of whole eye tissues from A/J, BALB/c, and C57BL/6 background mice. Examine ocular tissue from 3 different background mice that display varying rates of retinal degeneration.
Project description:The initial aim of this work was to understand the pathophysiology of Enhanced S-cone Syndrome (ESCS) that leads to retinal degeneration. Although ESCS was identified in humans decades ago and since then the causative genes have been elucidated, our understanding of the accompanying retinal degeneration is still poorly understood. Knockout of the Nrl transcription factor in mice produces a retina overpopulated with S-cone like photoreceptors along with absence of rod photoreceptors and recapitulates many of the phenotypic features seen in human ESCS patients. We wanted to study this murine model through a combinatorial genetic and structural approach to improve understanding of the disease process that leads to photoreceptor degeneration and blindness, potentially guiding future therapies. By using RNA-Sequencing (RNA-Seq) to examine mature wild type and Nrl-/- ocular tissues, we were able to determine global changes in their transcriptomes. The massively parallel RNA-sequencing experiment revealed new insight into the transcriptional mis-regulation in the ESCS murine model and revealed a change in gene expression in putative proteins involved in photoreceptor phagocytosis. Key photoreceptor ligands necessary for phagocyotsis, Tub and Tulp1, were down-regulated in the Nrl-/- retina. Down regulation of key retinoid metabolic genes, coupled with down-regulation of Tub and Tulp1, suggested a potential mechanism involving defective phagocytosis underlies the photoreceptor degeneration seen in ESCS. We report RNA-Seq experiments of whole eye and retinal tissues from wild type and Nrl transcription factor knockout mice on the C57BL/6 background. Examine two different ocular tissues in two mouse models of varying photoreceptor populations