Project description:Genetic dissection of the S rat genome has provided strong evidence for the presence of two interacting blood pressure (BP) quantitative trait loci (QTLs), termed QTL1 and QTL2, on rat chromosome 5. However, the identities of the underlying interacting genetic factors remain unknown. Further experiments targeted to identify the interacting genetic factors by the substitution mapping approach alone are difficult because of the interdependency of natural recombinations to occur at the two QTLs. We hypothesized that the interacting genetic factors underlying these two QTLs may interact at the level of gene transcription and thereby represent expression QTLs (eQTLs). To detect these interacting eQTLs, a custom QTL chip containing the annotated genes within QTL1 and QTL2 was developed and used to conduct a transcriptional profiling study of S and two congenic strains that retain either one or both the QTLs. The results uncovered an interaction between two transcription factors, DMRTA2 and NFIA. Further, the ‘biological signature’ elicited by these two transcription factors was differential between the congenic strain that retained LEW alleles at both QTL1 and 2 compared to the congenic strain that retained LEW alleles at QTL1 alone. A network of transcription factors potentially affecting BP could be traced, lending support to our hypothesis. Keywords: rat, hypertension, genetics, polygenic trait, microarray, gene expression
Project description:DEFINING A RAT BLOOD PRESSURE QUANTITATIVE TRAIT LOCUS TO A <81.8KB CONGENIC SEGMENT: COMPREHENSIVE SEQUENCING AND RENAL TRANSCRIPTOME ANALYSIS.
Project description:Genetic dissection of the S rat genome has provided strong evidence for the presence of two interacting blood pressure (BP) quantitative trait loci (QTLs), termed QTL1 and QTL2, on rat chromosome 5. However, the identities of the underlying interacting genetic factors remain unknown. Further experiments targeted to identify the interacting genetic factors by the substitution mapping approach alone are difficult because of the interdependency of natural recombinations to occur at the two QTLs. We hypothesized that the interacting genetic factors underlying these two QTLs may interact at the level of gene transcription and thereby represent expression QTLs (eQTLs). To detect these interacting eQTLs, a custom QTL chip containing the annotated genes within QTL1 and QTL2 was developed and used to conduct a transcriptional profiling study of S and two congenic strains that retain either one or both the QTLs. The results uncovered an interaction between two transcription factors, DMRTA2 and NFIA. Further, the âbiological signatureâ elicited by these two transcription factors was differential between the congenic strain that retained LEW alleles at both QTL1 and 2 compared to the congenic strain that retained LEW alleles at QTL1 alone. A network of transcription factors potentially affecting BP could be traced, lending support to our hypothesis. Pairs of Cy5 and Cy3 labeled targets were co-hybridized onto either a custom long oligonucleotide microarray for the interrogation of 231 genes encompassed by QTL1 and QTL2, or a TIGR rat cDNA array consisting of 26,401 probe elements representing 20,465 unique non-QTL genes. A âflip-dyeâ or âbalanced blockâ design was used as the experimental method of choice to account for potential dye-bias labeling effects. Six âbalanced blockâ normalized files are submitted for the long oligonucleotide array interrogating the hearts from S versus S.LEW(5)x6x9 animals, fourteen âflip-dyeâ hybridizations are submitted for the cDNA array interrogating the hearts from S versus S.LEW(5)x6x9 animals, and twelve âflip-dyeâ hybridizations are submitted for the cDNA array interrogating the hearts from S versus S.LEW(5)x6x11 animals. GPR and MEV files cannot be located.
Project description:Genome-wide association studies (GWAS) have identified blood pressure-related loci, but functional insights into causality and related molecular mechanisms lag behind. We functionally characterize 4608 genetic variants in linkage with blood pressure loci in vascular smooth muscle cells (VSMCs) and cardiomyocytes (CMs) by massively parallel reporter assays (MPRAs). Regulatory variants are in non-conserved loci, enriched in repeats, and alter trait-relevant transcription factor binding sites. Higher-order genome organization indicates that loci harboring regulatory variants converge in spatial hubs to control specific signaling pathways required for proper cardiovascular function. Modelling different variant allele frequencies by CRISPR prime editing led to expression changes of KCNK9, SFXN2, and PCGF6. We provide mechanistic insights into how regulatory variants converge their effects on blood pressure genes (i.e. ULK4, MAP4, CFDP1, PDE5A, 10q24.32), and cardiovascular pathways. Our findings support advances in molecular precision medicine to define functionally relevant variants and the genetic architecture of blood pressure genes.
Project description:Genome-wide association studies (GWAS) have identified blood pressure-related loci, but functional insights into causality and related molecular mechanisms lag behind. We functionally characterize 4608 genetic variants in linkage with blood pressure loci in vascular smooth muscle cells (VSMCs) and cardiomyocytes (CMs) by massively parallel reporter assays (MPRAs). Regulatory variants are in non-conserved loci, enriched in repeats, and alter trait-relevant transcription factor binding sites. Higher-order genome organization indicates that loci harboring regulatory variants converge in spatial hubs to control specific signaling pathways required for proper cardiovascular function. Modelling different variant allele frequencies by CRISPR prime editing led to expression changes of KCNK9, SFXN2, and PCGF6. We provide mechanistic insights into how regulatory variants converge their effects on blood pressure genes (i.e. ULK4, MAP4, CFDP1, PDE5A, 10q24.32), and cardiovascular pathways. Our findings support advances in molecular precision medicine to define functionally relevant variants and the genetic architecture of blood pressure genes.
Project description:Kidney samples from three Dahl Salt-sensitive S rats were compared with kidney samples from three S.R(9)x3A congenic rats. Keywords = Blood Pressure Keywords = Quantitative trait locus Keywords = QTL Keywords = hypertension Keywords = rat Keywords = congenic Keywords: parallel sample
Project description:Analysis of expression quantitative trait loci (eQTLs) using RNA derived from freshly harvested peripheral blood CD4+ lymphocytes from 200 asthmatics collected in clinical settings.
Project description:The overlap of congenic regions in an earlier substitution mapping study suggested the location of two blood pressure quantitative trait loci (QTL)-containing regions in the q-terminus of rat chromosome 3, QTL1 and the more distal, QTL2. Male SS/jr rats and two congenic substrain rats S.R(D3Mco36-D3Mco46) and S.R(D3Mco36-D3Got166) were maintained on a low salt (0.4% NaCl Harlan Teklad diet TD7034) diet until 39-41 days of age and then fed an intermediate (2% NaCl Harlan Teklad diet TD94217) salt diet for 28 days. These 3 rat strains will be hereafter referred to as S, S.R(ET3x1), and S.R(ET3x2), respectively. Both congenic substrains carry SR/jr (R)-rat alleles for QTL2 on an S-rat genetic background, while S.R(ET3x2) also carries R-rat alleles for QTL1. Renal gene expression analysis was used to identify differentially expressed genes or genes with altered activity within the S.R(ET3x2) congenic region. Keywords: strain differences in response to dietary changes
Project description:Despite recent advances in genomics, the identification of genes underlying complex diseases remains challenging. Inbred rat strains offer well-established experimental models to support the identification of susceptibility genes for diseases such as kidney damage associated with elevated blood pressure or hypertension. Here, we combined quantitative trait locus (QTL) mapping in two contrasting inbred rat strains with targeted next generation sequencing (NGS), compartment-specific transcriptome sequencing (RNA-Seq), and phenotype directed follow-up translational analysis.
Project description:The overlap of congenic regions in an earlier substitution mapping study suggested the location of two blood pressure quantitative trait loci (QTL)-containing regions in the q-terminus of rat chromosome 3, QTL1 and the more distal, QTL2. Male SS/jr rats and two congenic substrain rats S.R(D3Mco36-D3Mco46) and S.R(D3Mco36-D3Got166) were maintained on a low salt (0.4% NaCl Harlan Teklad diet TD7034) diet until 39-41 days of age. These 3 rat strains will be hereafter referred to as S, S.R(ET3x1), and S.R(ET3x2), respectively. At 39-41 days of age, half of the rats from each strain were fed a high (4% NaCl Harlan Teklad diet TD83033) salt diet and water ad libitum for 24 hours. Both congenic substrains carry SR/jr (R)-rat alleles for QTL2 on an S-rat genetic background, while S.R(ET3x2) also carries R-rat alleles for QTL1. Renal gene expression analysis was used to identify differentially expressed genes or genes with altered activity within the S.R(ET3x2) congenic region. Keywords: strain differences in response to dietary changes