Transcriptional responses of allotetraploid cotton species to salt stress
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ABSTRACT:
ORGANISM(S): Gossypium tomentosum
SUBMITTER: Alan Gingle
PROVIDER: E-GEOD-19966 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:exceptional example of evolutionary innovation is the single-celled seed trichome in Gossypium ("cotton fiber"). We have used fiber development in Gossypium as a system to understand how morphology can rapidly evolve. Fiber has undergone considerable morphological changes between the short, tightly adherent fibers of G. longicalyx and the derived long, spinable fibers of its closest relative, G. herbaceum, that facilitated cotton domestication. We conducted comparative gene expression profiling across a developmental time-course of fibers from G. longicalyx and G. herbaceum using microarrays with ~ 22,000 genes. Expression changes between stages were temporally protracted in G. herbaceum relative to G. longicalyx, reflecting a prolongation of the ancestral developmental program. Gene expression and GO analyses showed that many genes involved with stress responses were up-regulated early in G. longicalyx fiber development. Several candidate genes up-regulated in G. herbaceum have been implicated in regulating redox levels and cell elongation processes. Three genes previously shown to modulate hydrogen peroxide levels were consistently expressed in domesticated and wild cotton species with long fibers but expression was not detected by qRT-PCR in wild species with short fibers. Hydrogen peroxide is important for cell elongation, but at high concentrations it becomes toxic, activating stress processes that may lead to early onset of secondary cell wall synthesis and the end of cell elongation. These observations suggest that the evolution of long spinable fibers in cotton was accompanied by novel expression of genes assisting in the regulation of reactive oxygen species levels. Our data suggest a model for the evolutionary origin of a novel morphology through differential gene regulation causing prolongation of an ancestral developmental program. Keywords: Cotton, fiber, evolution, time-point, comparative genomic hybridization, stress response genes, H2O2 A balanced developmental loop design for microarray analysis was performed. For G. herbaceum (A1) and G. longicalyx (F), four fiber developmental time-points, 5, 10, 20 and 25 DPA were sampled. Within each species, hybridizations were performed between each pair of consecutive developmental stages by labeling one with Cy5 and the other with Cy3, and by closing the loop with a comparison of 25 and 5 dpa. In addition, 2 hybridizations were done between species at each time-point, using a dye swap for each pair. With three biological replications and 16 slides each, we generated gene expression data from a total of 48 microarrays.
2010-06-25 | E-GEOD-10228 | biostudies-arrayexpress
Project description:Background MeCP2, methyl-CpG-binding protein 2, binds to methylated cytosines at CpG dinucleotides, as well as to unmethylated DNA, and affects chromatin condensation. MECP2 mutations in females lead to Rett syndrome, a neurological disorder characterized by developmental stagnation and regression, loss of purposeful hand use and speech, stereotypic hand movements, deceleration of brain growth, autonomic dysfunction and seizures. Most mutations occur de novo during spermatogenesis. Located at Xq28, MECP2 is subject to X inactivation, and affected females are mosaic. Rare hemizygous males suffer from a severe congenital encephalopathy. Methods To identify pathways mis-regulated by MeCP2 deficiency, microarray-based global gene expression studies were carried out on cerebellum of Mecp2 mutant mice. We compared transcript levels in mutant/wildtype male sibs of two different MeCP2-deficient mouse models at 2, 4 and 8 weeks of age. Increased transcript levels were evaluated by real-time quantitative RT-PCR. Chromatin immunoprecipitation assays were used to document in vivo MeCP2 binding to promoter regions of candidate target genes. Results In the mutants, several hundred genes showed altered expression levels. Twice as many were increased than decreased, and only 27 genes were differentially expressed at more than one time point. The number of misregulated genes was 30% lower in mice with an exon 3 deletion (Mecp2tm1.1Jae) than in mice with a larger deletion (Mecp2tm1.1Bird). Between the mutants, few misregulated genes overlapped at each time point. Real-time quantitative RT-PCR assays validated increased transcript levels for four genes: Irak1, interleukin-1 receptor-associated kinase 1; Fxyd1, phospholemman, associated with Na, K-ATPase; Reln, encoding reelin, an extracellular signaling molecule essential for neuronal lamination and synaptic plasticity; and Gtl2/Meg3, an imprinted maternally expressed non-translated RNA that serves as a host gene for C/D box snoRNAs and microRNAs. Chromatin immunoprecipitation assays documented in vivo MeCP2 binding to promoter regions of Fxyd1, Reln, and Gtl2. Conclusions Transcriptional profiling of cerebellum failed to detect significant global changes in Mecp2-mutant mice. Increased transcript levels of Irak1, Fxyd1, Reln, and Gtl2 may contribute to the neuronal dysfunction in MeCP2-deficient mice and individuals with Rett syndrome. Our data provide testable hypotheses for future studies of the regulatory or signaling pathways that these genes act on. A genetic modification design type is where an organism(s) has had genetic material removed, rearranged, mutagenized or added, such as knock out. Computed
2007-08-15 | E-GEOD-8774 | biostudies-arrayexpress
Project description:This study is a quantitative trait linkage mapping study targeted at gene-environment interaction. A family of yeast derived from BY4716 and RM11-1a was grown in two carbon sources (glucose and ethanol) and expression profiled. The analysis revealed how the influence of genetic factors changes in different conditions. Abstract: The effects of genetic variants on phenotypic traits often depend on environmental and physiological conditions, but such gene–environment interactions are poorly understood. Recently developed approaches that treat transcript abundances of thousands of genes as quantitative traits offer the opportunity to broadly characterize the architecture of gene–environment interactions. We examined the genetic and molecular basis of variation in gene expression between two yeast strains (BY and RM) grown in two different conditions (glucose and ethanol carbon sources). We observed that most transcripts vary by strain and condition, with 2,996, 3,448, and 2,037 transcripts showing significant strain, condition, and strain–condition interaction effects, respectively. We expression profiled over 100 segregants derived from a cross between RM and BY in both growth conditions, and identified 1,555 linkages for 1,382 transcripts that show significant gene–environment interaction. At the locus level, local linkages, which usually correspond to polymorphisms in cis-regulatory elements, tend to be more stable across conditions, such that they are more likely to show the same effect or the same direction of effect across conditions. Distant linkages, which usually correspond to polymorphisms influencing trans-acting factors, are more condition-dependent, and often show effects in different directions in the two conditions. We characterized a locus that influences expression of many growth- related transcripts, and showed that the majority of the variation is explained by polymorphism in the gene IRA2. The RM allele of IRA2 appears to inhibit Ras/PKA signaling more strongly than the BY allele, and has undergone a change in selective pressure. Our results provide a broad overview of the genetic architecture of gene–environment interactions, as well as a detailed molecular example, and lead to key insights into how the effects of different classes of regulatory variants are modulated by the environment. These observations will guide the design of studies aimed at understanding the genetic basis of complex traits. Keywords: QTL This data set includes 24 parental arrays (6 of each parent in each condition, 218 segregant arrays (109 in both conditions), and 4 allele replacement arrays (IRA2 replacements in both backgrounds in both conditions). All arrays are from an unique biological sample, and many are randomized for dye (no dye-swaps on the same RNA sample). For the 24 parental arrays, there are three of each strain*condition*dye combination. The segregant arrays were randomized for dye. The replacement arrays are all of the Cy5 = experimental, Cy3 = reference type. All arrays are hybridized to a common reference consisting of an equal portions of RNA samples. from BY and RM grown in glucose and ethanol. Analysis was performed using default settings in Agilent Feature Extractor software versions 8.0-9.5. Spots were excluded if their intensity was below 350 or if they were flagged as non-uniformity outliers. Transcripts were considered good if they were present in all parental arrays (for the parental analysis) or 80% of all arrays in each condition for the segregant analysis.
2008-04-15 | E-GEOD-9376 | biostudies-arrayexpress
Project description:A major goal of biology is the construction of networks that predict complex system behavior. We combine multiple types of molecular data, including genotypic, expression, transcription factor binding site (TFBS), and protein-protein interaction (PPI) data previously generated from a number of yeast experiments in order to reconstruct causal gene networks. Networks based on different types of data are compared using metrics devised to assess the predictive power of a network. A network reconstructed by integrating genotypic, TFBS and PPI data is shown to be the most predictive. This network is used to predict causal regulators responsible for hot spots of gene expression activity in a segregating yeast population. The network is also shown to elucidate the mechanisms by which causal regulators give rise to larger-scale changes in gene expression activity. Predictions are prospectively validated to provide direct experimental evidence that predictive networks can be constructed by integrating multiple, appropriate data types. Keywords: allele replacement Allele replacement strains were created in two backgrounds: BY (BY4724 and BY4742), and RM11-1a, and compared to the parental type (BY4716 and RM11-1a). BY7g, BY9g, BY11g are BY4716, while RM7g, RM9g, and RM11g are RM11-1a. YAD350 is a MKT1 D30G replacement strain in BY4742 background. YLK804 is a SAL1-RM allele in BY4724 and YLK806 is a SAL1-BY allele in RM11-1a. All strains were grown in YNB + 2% glucose, with leucine, lysine, and uracil. YAD350 was also grown with histidine.
2008-06-15 | E-GEOD-11111 | biostudies-arrayexpress
Project description:Monoamine oxidase A (MAO-A), a mitochondrial enzyme that degrades monoamines including neurotransmitters, is highly expressed in basal cells of the normal human prostatic epithelium and in poorly differentiated (Gleason grades 4 and 5), aggressive prostate cancer (PCa). Clorgyline, an MAO-A inhibitor, induces secretory differentiation of normal prostate cells. We systematically assessed gene expression changes induced by clorgyline in E-CA cells using high-density oligonucleotide microarrays. Genes differentially expressed in treated and control cells were identified by Significance Analysis of Microarrays. Expression of genes of interest was validated by quantitative real-time polymerase chain reaction. time series design
2010-07-17 | E-GEOD-17167 | biostudies-arrayexpress
Project description:Gossypium barbadense is widely cultivated because of its extra-long staple cotton with superior luster, silkiness and high yield. These economically important traits were selected during initial domestication of an agronomically inferior wild ancestor, followed by millennia of human- mediated selection. To reveal the effects of this history on the cotton fiber transcriptome, we conducted comparative expression profiling on mechanically isolated fiber cells at three different stages encompassing early, mid, and late fiber elongation in wild (K101) and domesticated (Pima S-7) accessions, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes across developmental stages was different in the two accessions, with a shift toward greater change earlier in cultivated than in wild G. barbadense. Approximately 4200 genes were differentially expressed between wild and domesticated accessions at one or more of the stages studied. Domestication appears to have led to enhanced modulation of cellular redox levels and the avoidance or delay of stress-like processes. Prolonged fiber growth in cultivated relative to wild G. barbadense is associated with upregulation of signal transduction and hormone signaling genes and down-regulation of cell wall maturation genes. Clues are provided into the processes and genes that may unwittingly have been selected by humans during domestication and development of modern elite lines. Several of the transcriptomic differences between wild and domesticated G. barbadense described here appear to have parallels in a second domesticated cotton species, Gossypium hirsutum, suggesting that replicated domestication of two different species has resulted in overlapping, parallel, metabolic transformations. Two accessions of G. barbadense were studied, the elite cultivar, Pima S-7, and a wild accession from Bolivia, K101. Seeds of both accessions were sown in sterilized potting mix in the Pohl Conservatory at Iowa State University, Ames, IA, and three biological replicates were grown for 3-5 months. Flowers were tagged at anthesis and harvested at three time points, 2, 10, and 20 days postanthesis. For each of three biological replicates, ovules were excised, frozen in liquid nitrogen, and stored at -80C.
2008-11-13 | E-GEOD-13022 | biostudies-arrayexpress
Project description:Reactive oxygen species (ROS) play a prominent role in signal transduction and cellular homeostasis in plants. However, imbalances between generation and elimination of ROS can give rise to oxidative stress in growing cells. Because ROS are important to cell growth, ROS modulation could be responsive to natural or human-mediated selection pressure in plants. To study the evolution of oxidative stress related genes in a single plant cell, we conducted comparative expression profiling analyses of the elongated seed trichomes (‘‘fibers’’) of cotton (Gossypium), using a phylogenetic approach. We measured expression changes during diploid progenitor species divergence, allopolyploid formation and parallel domestication of diploid and allopolyploid species, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes in progenitor diploid species revealed significant up-regulation of ROS scavenging and potential signaling processes in domesticated G. arboreum. Similarly, in two independently domesticated allopolyploid species (G. barbadense and G. hirsutum) antioxidant genes were substantially up-regulated in comparison to antecedent wild forms. In contrast, analyses of three wild allopolyploid species indicate that genomic merger and ancient allopolyploid formation had no significant influences on regulation of ROS related genes. Remarkably, many of the ROS-related processes diagnosed as possible targets of selection were shared among diploid and allopolyploid cultigens, but involved different sets of antioxidant genes. Our data suggests that parallel human selection for enhanced fiber growth in several geographically widely dispersed species of domesticated cotton resulted in similar and overlapping metabolic transformations of the manner in which cellular redox levels have become modulated. We measured expression changes during diploid progenitor species divergence, allopolyploid formation and parallel domestication of diploid and allopolyploid species, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes was studied for domesticated G. arboreum and two independently domesticated allopolyploid species (G. barbadense and G. hirsutum). These were compared to three wild allopolyploid species. Three biological replicates were performed.
2009-07-24 | E-GEOD-17084 | biostudies-arrayexpress
Project description:To assess the relative contributions of the PKA and MAPK pathways in Ras stimulation of filamentation, we examined the change in transcriptional profile following activation of Ras in strains in which one of these two pathways has been severed. These arrays contain the experiments involving WT strain with glucose addition, Ras2G19V strain with galactose induction, tpk2-w strain as a control, and RasG19V activation in the tpk2-w background. Activation of Ras in the Σ1278b background – by galactose addition to a gal1 PGAL10-RAS2G19V strain - causes a massive restructuring of the transcription pattern of the cell, which closely resembles the changes induced by addition of glucose. To assess the extent to which these Ras-induced changes depended on signaling through PKA, we compared the expression profile following induction of activated Ras in a wild type background to that following induction of activated Ras in the bcy1 tpk1 tpk3 tpk2V218G. Keywords: time course RNA from strains grown as described was extracted using the RNeasy Mini Kit (Qiagen, California, USA) with mechanical disruption. RNA labeling and hybridization to Agilent oligonucleotide microarrays were done according to manufacturer’s instructions (Agilent Technologies, California, USA). RNA and cRNA concentrations were measured with NanoDrop (NanoDrop Technologies, Delaware, USA). 250ng labeled cRNA was used for each hybridization. The zero minute time point samples were labeled with Cy3 and others with Cy5. At least two technical replicates of each hybridization were performed. Hybridized microarrays were scanned with Agilent Microarray Scanner G2505B and the images were prepared for data analysis with Feature Extraction Software version 7.5 (Agilent Technologies, California, USA). Data were filtered and analyzed using PUMAdb based on the Stanford Microarray Database package.
2007-08-18 | E-GEOD-8805 | biostudies-arrayexpress
Project description:In order to further our understanding of the metabolic network of the malaria parasite, Plasmodium falciparum, we carried out a concurrent transcriptomic and metabolomic study of the parasite's intraerythrocytic developmental cycle. These microarray data were generated to compare the expression levels of metabolic enzymes to the concentrations of their associated metabolites over the 48-hour life cycle. Sorbitol-synchronized Plasmodium falciparum (3D7 strain) was grown in tissue culture flasks in incubators according to standard protocols. Immediately after reinvasion, and at 8-hour intervals thereafter, parasites were harvested by centrifugation. For each timepoint, 0.5 mL of packed RBC (10% parasitemia) was pelleted by centrifugation, washed once in PBS and flash-frozen in liquid nitrogen. Total RNA isolation and amino-allyl cDNA labeling were as previously described (Bozdech et al., 2003). A pool of 3D7 total RNA from all intraerythrocytic developmental stages was generated and used as the reference sample. For DNA microarray hybridization, pool cDNA was coupled to Cy3 dye, while cDNA from an individual timepoint was coupled to Cy5 dye. DNA microarrays were scanned using an Axon 4200A scanner and images analyzed using Axon GenePix software (Axon Instruments, Union City, CA, USA). Microarray data were stored and analyzed using our in-house database PUMAdb (Princeton University MicroArray database). All data for individual arrays were normalized by a global normalization using unflagged features with >= 65% of pixels one or more standard deviations over local background. All unflagged spots were selected and extracted for further analysis. Data were filtered to remove oligos more than 1 datapoint missing across the timeseries, log2 transformed, mean centered, ordered by the timing of their peak expression level, and visualized with Java Treeview (Saldanha, 2004) (Table S3).
2009-01-23 | E-GEOD-14524 | biostudies-arrayexpress
Project description:In this study, the researchers isolated a colorless waxy solid from the chloroform extract of Allium stipitatum as Compound 1. They demonstrated compound 1 is a potent bactericidal agent against nonreplicating Mycobacterium tuberculosis. Using microarray technology the authors report gene expression profiles in cells treated with either 2, 5, or 10 ug/ml of compound 1 or an equivalent amount of DMSO as control for 6 h. Gene expression studies revealed that transcriptional profiles elicited in response to compound 1 were similar to the profiles generated during treatment of cells with compounds such as menadione and 8-quinolinol that result in oxidative stress. They included the thioredoxin system components encoded by trxB2 and trxC as well as several genes associated with the heat shock response such as clpB, sigH, dnaJ, dnaK, hsp, Rv0331, Rv3463, Rv3054c, and Rv1334-Rv1335. These results suggest that compound 1 possibly generates damaged proteins and other oxidative stress signals as part of its mechanism of action. The following is the full abstract of this published study. O'Donnell G, et al. (2009) J Nat Prod 72(3):360-365 From Allium stipitatum, three pyridine-N-oxide alkaloids (1-3) possessing disulfide functional groups were isolated. The structures of these natural products were elucidated by spectroscopic means as 2-(methyldithio)pyridine-N-oxide (1), 2-[(methylthiomethyl)dithio]pyridine-N-oxide (2), and 2,2'-dithio-bis-pyridine-N-oxide (3). The proposed structure of 1 was confirmed by synthetic S-methylthiolation of commercial 2-thiopyridine-N-oxide. Compounds 1 and 2 are new natural products, and 3 is reported for the first time from an Allium species. All compounds were evaluated for activity against fast-growing species of Mycobacterium, methicillin-resistant Staphylococcus aureus, and a multidrug-resistant (MDR) variants of S. aureus. Compounds 1 and 2 exhibited minimum inhibitory concentrations (MICs) of 0.5-8 mug/ml against these strains. A small series of analogues of 1 were synthesized in an attempt to optimize antibacterial activity, although the natural product had the most potent in vitro activity. In a whole-cell assay at 30 mug/ml, 1 was shown to give complete inhibition of the incorporation of (14)C-labeled acetate into soluble fatty acids, indicating that it is potentially an inhibitor of fatty acid biosynthesis. In a human cancer cell line antiproliferative assay, 1 and 2 displayed IC(50) values ranging from 0.3 to 1.8 muM with a selectivity index of 2.3 when compared to a human somatic cell line. Compound 1 was evaluated in a microarray analysis that indicated a similar mode of action to menadione and 8-quinolinol by interfering with the thioredoxin system and up-regulating the production of various heat shock proteins. This compound was also assessed in a mouse model for in vivo toxicity. A dose response design type examines the relationship between the size of the administered dose and the extent of the response of the organism(s). Compound Based Treatment: Allium stipitatum (garlic) extract dose_response_design
2009-08-15 | E-GEOD-17640 | biostudies-arrayexpress