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GSE7743
Arabidopsis thaliana
21 Downloadable Samples
Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Exposure to high irradiance results in dramatic changes in nuclear gene expression in plants. However, little is known about the mechanisms by which changes in irradiance are sensed and how the information is transduced to the nucleus to initiate the genetic response. To investigate whether the photoreceptors are involved in the response to high irradiance, we analyzed expression of ELIP1, ELIP2, APX2 and LHCB2.4 in the phyA, phyB, cry1 and cry2 photoreceptor mutants and hy5 and hyh transcription factor mutants. Following exposure to high intensity white light for 3 h (HL, 1000 micro mol quanta m-2 s-1) expression of ELIP1/2 and APX2 was strongly induced and LHCB2.4 expression repressed in wild type. The cry1 and hy5 mutants showed specific mis-regulation of ELIP1/2 and we show that the induction of ELIP1/2 expression is mediated via CRY1 in a blue light intensity-dependent manner. Furthermore, using the Affymetrix Arabidopsis 24K Gene-Chip we showed that 77 of the HL responsive genes are regulated via CRY1, and 26 of those genes were also HY5 dependent. As a consequence of the mis-regulation of these genes the cry1 mutant displayed a high irradiance-sensitive phenotype with significant photoinactivation of PSII, indicated by reduced Fv/Fm. Thus, we describe a novel function of CRY1 in mediating plant responses to high irradiances that is essential to the induction of photoprotective mechanisms. This indicates that high irradiance can be sensed in a chloroplast-independent manner by a cytosolic/nucleic component.
Publication Title
Genome-wide gene expression analysis reveals a critical role for CRYPTOCHROME1 in the response of Arabidopsis to high irradiance.
Sample Metadata Fields
No sample metadata fields
View Samples- Escherichia coli
- 2 Downloadable Samples
- Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Antitoxins are becoming recognized as proteins that regulate more than their own synthesis; for example, we found previously that antitoxin MqsA represses the gene encoding the stationary phase sigma factor RpoS. Here, we investigated the physiological role of antitoxin DinJ of the DinJ/YafQ toxin/antitoxin system and found DinJ also affects the general stress response by decreasing RpoS levels. Corroborating the reduced RpoS levels upon producing DinJ, catalase activity, cell adhesins, and cyclic diguanylate decreased while swimming increased. Using a transcriptome search and DNA-binding assays, we determined that the mechanism by which DinJ reduces RpoS is by repressing cspE which encodes cold-shock protein CspE that inhibits translation of rpoS mRNA. Hence, DinJ influences the general stress response indirectly by regulating cspE.
Publication Title
Antitoxin DinJ influences the general stress response through transcript stabilizer CspE.
Sample Metadata Fields
Time
View Samples- Homo sapiens
- 11 Downloadable Samples
- Affymetrix Human Genome U133A Array (hgu133a)
Description
Multipotent progenitor cells (MPs) have been observed in human kidneys and particularly in Bowman's capsule and proximal tubules. The kidney owns the ability to repair local damage and renal MPs may play a role in the regenerative processes. Microarray technology was applied to identify differentially expressed genes among resident MPs isolated from glomeruli and tubules of normal renal tissue, renal proximal tubular epithelial cells (RPTECs) and mesenchymal stem cells (MSCs).
Publication Title
TLR2 plays a role in the activation of human resident renal stem/progenitor cells.
Sample Metadata Fields
Subject
View Samples- Citrus sinensis
- 12 Downloadable Samples
- Affymetrix Citrus Genome Array (citrus)
Description
We have used the citrus GeneChip array (GPL5731) to survey the transcription profiles of sweet orange in response to the bacterial pathogens Xanthomonas axonopodis pv. citri (Xac) and Xanthomonas axonopodis pv. aurantifolii (Xaa). Xac is the causal agent of the citrus canker disease on a wide range of citrus species, including sweet oranges (Citrus sinensis). On the other hand, Xaa is pathogenic to Mexican lime (Citrus aurantifolia) only, and in sweet orange it triggers a defense response. In order to identify the genes induced during the defense response (Xaa-responsive genes) or citrus canker development (Xac-responsive genes), we conducted microarrays hybridization experiments at 6 and 48 hours after bacterial infiltration (habi). The analysis revealed that genes commonly modulated by Xac and Xaa are associated with basal defenses normally triggered by pathogen-associated molecular patterns, including those involved in reactive oxygen species production and lignification. Significantly, Xac-infected leaves showed considerable changes in the transcriptional profiles of defense-, cell wall-, vesicle trafficking- and cell growth-related genes between 6 and 48 habi. This is consistent with the notion that Xac suppresses host defenses near the beginning of the infection and simultaneously changes the physiological status of the host to promote cell enlargement and division. Finally, Xaa triggered a MAP kinase signaling pathway involving WRKY and ethylene-responsive transcriptional factors known to activate downstream defense genes.
Publication Title
Transcriptional analysis of the sweet orange interaction with the citrus canker pathogens Xanthomonas axonopodis pv. citri and Xanthomonas axonopodis pv. aurantifolii.
Sample Metadata Fields
No sample metadata fields
View Samples- Escherichia coli k-12
- 2 Downloadable Samples
- Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Persister cells are a sub-population of all bacterial cultures which exhibit a non-inheritable, multi-drug tolerance when subjected to lethal antibiotic challenge. These persisters arise as a result of metabolic dormancy, and can resume growth subsequent to antibiotic challenge, leading to recalcitrance of bacterial infections.
Publication Title
Phosphodiesterase DosP increases persistence by reducing cAMP which reduces the signal indole.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 9 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Though it is well established that immunological functions of CD4+ T cells are time of day-dependent, the underlying molecular mechanisms remain largely obscure. To address the question whether T cells themselves harbor a functional clock driving circadian rhythms of immune function, we analyzed clock gene expression and immune responses of CD4+ T cells purified from blood of healthy subjects at different time points throughout the day. Circadian clock function as well as immune function was further analyzed in cultivated T cells and circadian clock reporter systems. We found robust rhythms of clock gene expression as well as, after stimulation, of IFN-g production and CD40L expression in both freshly isolated and in cultured CD4+ T cells. Moreover, circadian luciferase reporter activities in CD4+ T cells and in thymic sections from PER2::LUCIFERASE reporter mice suggest that endogenous T cell clock rhythms are self-sustained under constant culture conditions. Microarray analysis of stimulated CD4+ T cell cultures revealed a rhythmic regulation of the NF-kB pathway as a candidate mechanism regulating circadian immune responses. Collectively, these data demonstrate for the first time that CD4+ T cell responses are regulated by an intrinsic cellular circadian oscillator capable of driving rhythmic adaptive immune responses in vitro and in vivo.
Publication Title
Circadian clocks in mouse and human CD4+ T cells.
Sample Metadata Fields
Specimen part, Time
View Samples- Mus musculus
- 20 Downloadable Samples
Illumina HiSeq 2000
Description
Purpose: The outer blood-retina barrier is established through the coordinated terminal maturation of the retinal pigment epithelium (RPE), fenestrated choroid endothelial cells (ECs) and Bruch’s membrane, a highly organized basement membrane that lies between both cell types. Here we study the contribution of choroid ECs to this process by comparing their gene expression profile before (P5) and after (P30) the critical postnatal period when mice acquire mature visual function. Methods: ECs from P5 and P30 mice were labeled in vivo by retro-orbital injection of fluorescently-labeled anti-VE-Cadherin. After 10 minutes, mice were euthanized, eyeballs were enucleated and the anterior segment was discarded. After removal of the neural retina, RPE/choroid was mechanically dissected from the sclera and digested. ECs were isolated by flow cytometry and processed immediately for RNA extraction. Results: Transcriptome analyses show that whereas P5 choroid EC transcriptome is preferentially enriched in cell cycle- and chromosome-related transcripts, reflecting an immature phenotype, the transcriptome of adult (P30) choroid ECs is enriched in genes encoding proteins involved in ‘biological adhesion’, including a variety of extracellular matrix (ECM)-related genes. Conclusion: these results strongly suggest that mature choroid ECs actively participate in extracellular matrix assembly and regulation. Overall design: Transcriptome of choroid ECs isolated from P5 and P30 mice (3 independent isolations, 7 animals per isolation) was determined using the Illumina HiSeq2000 platform. Upon quality control using FastQC, raw reads were aligned to the mouse genome (mm9) using TopHat with default parameters. CuffLinks with GC and upper quartile normalization was then used to calculate normalized expression levels.
Publication Title
Concerted regulation of retinal pigment epithelium basement membrane and barrier function by angiocrine factors.
Sample Metadata Fields
Specimen part, Cell line, Subject
View Samples- Escherichia coli
- 3 Downloadable Samples
- Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
E. coli K-12 BW25113 persister cells generated via H202 pre-treatment and deletion of rpoS, relative to BW25113 wild-type stationary phase gene expression. Persister cells were generated following exposure to ampicillin 20 ug/mL.
Publication Title
Bacterial persistence increases as environmental fitness decreases.
Sample Metadata Fields
Specimen part, Disease, Treatment, Time
View Samples- Escherichia coli k-12
- 2 Downloadable Samples
- Affymetrix E. coli Genome 2.0 Array (ecoli2)
Description
Persisters are a subpopulation of metabolically-dormant cells in biofilms that are resistant to antibiotics; hence, understanding persister cell formation is important for controlling bacterial infections. Previously we discerned that MqsR and MqsA of Escherichia coli are a toxin/antitoxin pair that influence persister cell production via their regulation of Hha, CspD, and HokA. Here, to gain more insights into the origin of persisters, we used protein engineering to increase the toxicity of toxin MqsR by reasoning it would be easier to understand the effect of this toxin if it were more toxic. We found that two mutations (K3N and N31Y) increase the toxicity four fold and increase persistence 73 fold compared to native MqsR by making the protein less labile. A whole transcriptome study revealed that the MqsR variant represses acid resistance genes (gadABCEWX and hdeABD), multidrug resistance genes (mdtEF), and osmotic resistance genes (osmEY). Corroborating these microarray results, deletion of rpoS as well as the genes that the master stress response regulator RpoS controls, gadB, gadX, mdtF, and osmY, increased persister formation dramatically to the extent that nearly the whole population became persistent. Therefore, the more toxic MqsR increases persistence by decreasing the ability of the cell to respond to antibiotic stress through its RpoS-based regulation of acid resistance, multidrug resistance, and osmotic resistance systems.
Publication Title
Bacterial persistence increases as environmental fitness decreases.
Sample Metadata Fields
Specimen part, Time
View Samples- Mus musculus
- 33 Downloadable Samples
- Illumina mouseRef-8 v1.1 expression beadchip
Description
The specific binding of transcription factors to cognate sequence elements is thought to be critical for the generation of specific gene expression programs. The transcription factors nuclear factor kB (NF-kB) and the interferon (IFN) regulatory factors (IRFs) bind to the kB site and the interferon response element (IRE), respectively, of target genes, and they are activated in macrophages after exposure to pathogens. However, how these factors produce pathogen-specific inflammatory and immune responses remains poorly understood. Combining top-down and bottom-up systems biology approaches, we have identified the NF-kB p50 homodimer (p50:p50) as a regulator of IRF responses. First, unbiased genome-wide expression analysis revealed that p50 repressed a subset of IFN-inducible genes through a previously uncharacterized subclass of guanine-rich IRE (G-IRE) sequences, which was substantiated by biochemical and structural analyses. Second, mathematical modeling predicted that p50:p50 might enforce the stimulus-specificity of composite promoters. Indeed, the production of the antiviral regulator IFN-b was rendered stimulus-specific by the binding of p50:p50 to the G-IREcontaining IFNb enhancer to suppress cytotoxic IFN signaling. Specifically, a deficiency in p50 resulted in the inappropriate production of IFN-b in response to bacterial DNA sensed by Toll-like receptor 9. This role for NF-kB p50 in enforcing the specificity of the cellular response to pathogens by binding to a previously uncharacterized subset of IRE sequences alters our understanding of how the NF-kB and IRF signaling systems cooperate to regulate antimicrobial immunity.
Publication Title
The specificity of innate immune responses is enforced by repression of interferon response elements by NF-κB p50.
Sample Metadata Fields
Specimen part, Time
View Samples