Unknown,Transcriptomics,Genomics,Proteomics

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Transcriptional profiling with a Blood Pressure QTL interval-specific oligonucleotide array

ABSTRACT: Although the evidence for a genetic predisposition to human essential hypertension is compelling, the genetic control of blood pressure (BP) is poorly understood. The Dahl salt-sensitive (S) rat is a model for studying the genetic component of BP. Using this model we previously reported the identification of 16 different genomic regions that contain one or more BP quantitative trait loci (QTLs). The proximal region of rat chromosome 1 contains multiple BP QTLs. Of these, we have localized the BP QTL1b region to a 13.5cM (20Mb) region. Interestingly, five additional independent studies in rats and four independent studies in humans have reported genetic linkage for BP control by regions homologous to QTL1b. To view the overall renal transcriptional topography of the positional candidate genes for this QTL, we sought a comparative gene expression profiling between a congenic strain containing QTL1b and control S rats by employing: (1) a saturated QTL1b interval specific oligonucleotide array, and (2) a whole genome cDNA microarray representing 20,465 unique genes that are positioned outside the QTL. Results indicated that 19 out of the 231 positional candidate genes for this QTL are differentially expressed between the two strains tested. Surprisingly, over 1,500 genes outside of QTL1b were differentially expressed between the two rat strains. Integrating the results from the two approaches revealed at least one complex network of transcriptional control initiated by the positional candidate Nr2f2. This network appears to account for the majority of gene expression differences occurring outside of the QTL interval. Further substitution mapping is currently underway to test the validity of each of these differentially expressed positional candidate genes. These results demonstrate the importance of using a saturated oligonucleotide array for identifying and prioritizing differentially expressed positional candidate genes of a BP QTL. Pairs of Cy5 and Cy3 labeled targets were co-hybridized onto either the oligonucleotide microarray or a custom TIGR rat cDNA array consisting of 26,401 probe elements representing 20,465 unique non-QTL1b genes. A âflip-dyeâ design was used as the experimental method of choice to account for potential dye-bias labeling effects. Seven âflip dyeâ normalized files are submitted for the oligonucleotide array and twelve individual hybridizations are submitted for the cDNA array.

ORGANISM(S): Rattus norvegicus

SUBMITTER: Razvan Sultana

PROVIDER: E-GEOD-1622 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Transcriptional profiling with a blood pressure QTL interval-specific oligonucleotide array.

Joe Bina B Letwin Noah E NE Garrett Michael R MR Dhindaw Seema S Frank Bryan B Sultana Razvan R Verratti Kathleen K Rapp John P JP Lee Norman H NH

Physiological genomics 20051004 3

Although the evidence for a genetic predisposition to human essential hypertension is compelling, the genetic control of blood pressure (BP) is poorly understood. The Dahl salt-sensitive (S) rat is a model for studying the genetic component of BP. Using this model, we previously reported the identification of 16 different genomic regions that contain one or more BP quantitative trait loci (QTLs). The proximal region of rat chromosome 1 contains multiple BP QTLs. Of these, we have localized the B ...[more]

PMID: 16204469

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Project description:Although the evidence for a genetic predisposition to human essential hypertension is compelling, the genetic control of blood pressure (BP) is poorly understood. The Dahl salt-sensitive (S) rat is a model for studying the genetic component of BP. Using this model we previously reported the identification of 16 different genomic regions that contain one or more BP quantitative trait loci (QTLs). The proximal region of rat chromosome 1 contains multiple BP QTLs. Of these, we have localized the BP QTL1b region to a 13.5cM (20Mb) region. Interestingly, five additional independent studies in rats and four independent studies in humans have reported genetic linkage for BP control by regions homologous to QTL1b. To view the overall renal transcriptional topography of the positional candidate genes for this QTL, we sought a comparative gene expression profiling between a congenic strain containing QTL1b and control S rats by employing: (1) a saturated QTL1b interval specific oligonucleotide array, and (2) a whole genome cDNA microarray representing 20,465 unique genes that are positioned outside the QTL. Results indicated that 19 out of the 231 positional candidate genes for this QTL are differentially expressed between the two strains tested. Surprisingly, over 1,500 genes outside of QTL1b were differentially expressed between the two rat strains. Integrating the results from the two approaches revealed at least one complex network of transcriptional control initiated by the positional candidate Nr2f2. This network appears to account for the majority of gene expression differences occurring outside of the QTL interval. Further substitution mapping is currently underway to test the validity of each of these differentially expressed positional candidate genes. These results demonstrate the importance of using a saturated oligonucleotide array for identifying and prioritizing differentially expressed positional candidate genes of a BP QTL. Keywords: : rat, hypertension, genetics, polygenic trait, microarray, gene expression

Project description:Large-scale gene expression affected by salt stress was analyzed with tomato seedlings (Lycoperson esculentum Mill cv. Money Maker) by a cDNA microarray (Tom1). The significantly differentially expressed genes (5% Benjamini-Hochberg false discovery rate) consisted of 1757 sequences in the analyzed tissues (cotyledons + shoot tip). Genes with over 2 fold difference were selected from the list and further categorized into different function and cellular processes. Tomato homologous genes for the chaperone proteins, antioxidant enzymes (catalase and peroxidase), and ion transporters (Na+-driven multidrug efflux pump, vacuolar ATPase, and others) were induced. The ACC oxidase and ethylene-responsive gene tomato homologs had higher transcript level after salt treatment. Multiple members with different expression patterns were identified for the bZIP, WRKY, and MADS-box transcription regulator. Different genes in the signal transduction pathway, such as the protein kinases (Shaggy kinase, mitogen-activated protein kinase, ethylene receptor neverripe, and others), protein phosphatases, calmodulin, G-protein, and the N- myristoyltransferase, were regulated by salt stress. Most of the protease and the inhibitor homologs were suppressed by salt stress. In addition, different isoforms of cytochrome P450, genes for polyamine biosynthesis (putrescine and proline) and detoxification compounds (glutathione and thioredoxin), several key enzyme genes in the metabolic pathways of carbohydrates, amino acids, and fatty acids, were also affected by salt treatment. This study has provided a set of candidate genes, especially those in the regulatory machinery that can be further investigated to define salt stress in tomato and other plant species. Keywords: treatment response Effect of 75mM NaCl on gene’s expression in tomato seedlings, Lycoperscon esculentum Mill. cv. Money Maker after 17 d of treatment. Each sample represents a pool of same tissue 20 seedlings grown in two flasks. Experiment was done in triplicate.

Project description:To provide a broad analysis of gene expression changes in developing embryos from a solanaceous species, we produced amplicon-derived microarrays with 7741 ESTs isolated from Solanum chacoense ovules bearing embryos from all developmental stages. Our aims were to: 1) identify genes expressed in a tissue-specific and temporal-specific manner; 2) define clusters of genes showing similar patterns of spatial and temporal expression; and 3) identify stage-specific or transition-specific candidate genes for further functional genomic analyses.We analyzed gene expression during S. chacoense embryogenesis in a series of experiments with probes derived from ovules isolated before and after fertilization (from 0 to 22 days after pollination), and from leaves, anthers, and styles. From the 6374 unigenes present in our array, 1024 genes were differentially expressed (? ±2 fold change, p value ? 0.01) in fertilized ovules and only limited expression overlap was observed between these genes and the genes expressed in the other tissues tested, with more than three quarters of the fertilization-regulated genes specifically or predominantly expressed in ovules. During embryogenesis three major expression profiles corresponding to early, middle and late stages of embryo development were identified. From the early and middle stages, a large number of genes corresponding to cell cycle, DNA processing, signal transduction, and transcriptional regulation were found. Defense and stress response-related genes were found in all stages of embryo development. Protein biosynthesis genes, genes coding for ribosomal proteins and other components of the translation machinery were highly expressed in embryos during the early stage. Genes for protein degradation were overrepresented later in the middle and late stages of embryo development. As expected, storage protein transcripts accumulated predominantly in the late stage of embryo development. Our analysis provides the first study in a solanaceous species of the transcriptional program that takes place during the early phases of plant reproductive development, including all embryogenesis steps during a comprehensive time-course. Our comparative expression profiling strategy between fertilized and unfertilized ovules identified a subset of genes specifically or predominantly expressed in ovules while a closer analysis between each consecutive time points allowed the identification of a subset of stage-specific and transition-specific genes. We produced amplicon-derived microarrays with 7741 ESTs isolated from Solanum chacoense ovules bearing embryos from all developmental stages. To monitor the expression pattern from genes involved in fertilization and embryogenesis processes, flowers were hand-pollinated and ovules were isolated every two days during a 22 days period after pollination. Four independent biological replicates were produced from each time points. In addition, to isolate genes specifically or predominantly expressed in ovules, four biological replicates of leaf, anther, and style tissue mRNA preparations were individually hybridized against unfertilized ovule mRNAs and compared with the data obtained from unfertilized and fertilized ovules at various time points after pollination. To estimate reproducibility and to produce control data for statistical analysis, a large number of unfertilized ovules were isolated and separated between seven independent control groups. RNA from randomly selected pairs of control was hybridized on six microarrays. 6374 unigenes present in our array in duplicate.

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Transcriptional profiling with a Blood Pressure QTL interval-specific oligonucleotide array

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Transcriptional profiling with a blood pressure QTL interval-specific oligonucleotide array.

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