Quorum sensing, a cell-to-cell communication system based on small signal molecules, is employed by the human pathogen Pseudomonas aeruginosa to regulate virulence and biofilm development. Moreover, regulation by small trans-encoded RNAs has become a focal issue in virulence gene expression of bacterial pathogens. In this study, we have identified the small RNA PhrS as an activator of PqsR synthesis, one of the key quorum sensing regulators in P. aeruginosa. Genetic studies revealed a novel mode of regulation by a sRNA, whereby PhrS uses a base-pairing mechanism to activate a short upstream open reading frame to which the pqsR gene is translationally coupled. Expression of phrS is induced by the oxygen-responsive regulator ANR when the oxygen supply decreases. Thus, PhrS is the first bacterial sRNA that provides a regulatory link between oxygen availability and quorum sensing, which may impact on oxygen-limited growth in P. aeruginosa biofilms.
The small RNA PhrS stimulates synthesis of the Pseudomonas aeruginosa quinolone signal.
No sample metadata fields
View SamplesWe have studied the regulatory potential of MYST1-(MOF)-containing MSL and NSL complexes in mouse embryonic stem cells (ESCs) and neuronal progenitors. We find that both complexes influence transcription by binding to promoters as well as TSS-distal enhancer regions. In contrast to flies, the MSL complex is not enriched on the X chromosome yet it is crucial for mammalian X chromosome regulation as it specifically regulates Tsix ncRNA, the major repressor of Xist lncRNA. MSL depletion leads to severely decreased Tsix expression, reduced REX1 recruitment, and consequently accumulation of Xist RNA in ESCs. The NSL complex provides additional, Tsix-independent repression of Xist by maintaining pluripotency. MSL and NSL complexes therefore act synergistically by using distinct pathways to ensure a fail-safe mechanism for the repression of X inactivation in ESCs. Overall design: We have performed ChIP-seq of KANSL3, MCRS1, MOF, MSL1 and MSL2 in mouse ESCs, and KANSL3, MOF and MSL2 in NPCs, in duplicate and normalised against their inputs. We have also performed RNA-seq following knockdown of Kansl3, Mof, Msl1 and Msl2 mouse embryonic stem cells in triplicate. NB: Kansl3 and Mof knockdown-RNAseq are analyzed against their own scrambled controls, and Msl1 and Msl2 against another scrambled control triplicate. siMCRS1 & siMOF were compared to scrambled1 (scr1) siMsl1 and siMsl2 were compared to scr2 siNsl3 was compared to scr3
MOF-associated complexes ensure stem cell identity and Xist repression.
No sample metadata fields
View SamplesThe RNA-binding protein RC3H1 (also known as ROQUIN) promotes TNFalpha mRNA decay via a 3''UTR constitutive decay element (CDE). Here, we applied PAR-CLIP to human RC3H1 to identify about 3800 mRNA targets with more than 16000 binding sites. A large number of sites are distinct from the consensus CDE and revealed a structure-sequence motif with U-rich sequences embedded in hairpins. RC3H1 binds preferentially short-lived and DNA damage induced mRNAs, indicating a role of this RNA-binding protein in the posttranscriptional regulation of the DNA damage response. Intriguingly, RC3H1 affects expression of NF-kB pathway regulators such as IkBalpha and A20. RC3H1 uses roquin and Zn-finger domains to contact a binding site in the A20 3''UTR, demonstrating a not yet recognized mode of RC3H1 binding. Knockdown of RC3H1 resulted in increased A20 protein expression, thereby interfering with IkB kinase and NF-kB activities, demonstrating that RC3H1 can modulate the activity of the IKK/NF-kB pathway. Overall design: We measured global mRNA decay rates in mock and RC3H1/RC3H2-depleted HEK293 cells. Transcription was blocked by Actinomycin D zero, one or two hours before harvesting. Total RNA was isolated in two biological replicates and subjected to polyA selection followed by high-throughput sequencing.
RC3H1 post-transcriptionally regulates A20 mRNA and modulates the activity of the IKK/NF-κB pathway.
No sample metadata fields
View SamplesEssential metals such as iron are required for healthy plant growth. Fe is an important cofactor and catalytic element in many biological processes. Fe and other metals can also be toxic when present in excess. Therefore plants have mechanisms of metal homeostasis which involve coordination of metal ion transporters for uptake, translocation and compartmentalisation. The NAS genes are supposed to play an important role in Fe homeostasis. They are coding for enzymes called nicotianaminesynthase (NAS), which synthesize nicotianamine (NA) by a one-step condensation reaction of three molecules S-adenosyl-methionine. NA acts as a chelator for Fe, Cu, Ni and Zn and might be involved in the transport and allocation of Fe throughout the plant. We generated quadruple T-DNA insertion mutant nas plants to investigate NA function as described in Klatte et al., 2009, Plant Physiol. The nas4x-1 plants show an interveinal leaf chlorosis when turning from vegetative to reproductive stage, which intensifies when growing under Fe deficiency conditions. nas4x-1 plants have strongly reduced NA contents and show an elevated Fe deficiency response in roots. By performing microarray experiments we want to reveal global changes on transcriptional level in roots and leaves of nas4x-1 mutant compared to wild type plants grown under Fe supply and Fe deficiency conditions, respectively. The loss of NAS genes has a strong impact on the regulation of other metal homeostasis genes and allows to draw conclusions about nicotianamine function in metal homeostasis of A.thaliana.
Transcriptome analysis by GeneTrail revealed regulation of functional categories in response to alterations of iron homeostasis in Arabidopsis thaliana.
Specimen part
View SamplesWe applied Next-Generation Sequencing (NGS) to miRNAs from blood samples of 48 AD (Alzheimer''s Disease) patients and 22 unaffected controls, yielding a total of 140 unique mature miRNAs with significantly changed expression level. Of these, 82 were higher and 58 lower abundant in samples from AD patients. We selected a panel of 12 miRNAs for a qRT-PCR analysis on a larger cohort of 202 samples including not only AD patients and healthy controls but also patients with other CNS illnesses: Multiple Sclerosis, Parkinson''s Disease, Major Depression, Bipolar Disorder, Schizophrenia, and Mild Cognitive Impairment, which is assumed to represent a transitional period before the development of AD. MiRNA target enrichment analysis of the selected 12 miRNAs indicated an involvement of miRNAs in nervous system development, neuron projection, neuron projection development, and neuron projection morphogenesis, respectively. Using this 12-miRNA signature we were able to differentiate between AD and controls with an accuracy of 93.3%, a specificity of 95.1%, and a sensitivity of 91.5%. The differentiation of AD from other neurological diseases was possible with accuracies between 73.8% and 77.8%. The differentiation of the other CNS disorders from controls yielded even higher accuracies. Overall design: Examination of the miRNA profile in blood samples of 48 AD patients and 22 controls
A blood based 12-miRNA signature of Alzheimer disease patients.
Sex, Age, Subject
View SamplesHypoxia protects cancer cells from chemotherapeutic drug-induced cell death.
TMEM45A is essential for hypoxia-induced chemoresistance in breast and liver cancer cells.
Cell line
View SamplesWe compared the gene expression of A549 cells following 24 and 48 hours of treatment with a no-observed-effect level dose of cisplatin. The objective of the study is to identify genes that are differentially expressed in response to sub-lethal doses of cisplatin. This study helps identify not only treatment responses but also changes in gene expression that may confer cytoprotective mechanisms that allow these cells to survive treatment and to develop treatment resistance.
Combined Use of Gene Expression Modeling and siRNA Screening Identifies Genes and Pathways Which Enhance the Activity of Cisplatin When Added at No Effect Levels to Non-Small Cell Lung Cancer Cells In Vitro.
Cell line, Treatment, Time
View SamplesDuring senescence of detached rice leaves, tryptophan (Trp) and Trp-derived secondary metabolites such as serotonin and 4-coumaroylserotonin accumulated in concert with methanol (MeOH) production. This senescence-induced MeOH induction was closely associated with levels of pectin methylesterase (PME)1 mRNA and PME enzyme activity. Exogenous challenge of detached rice leaves with 1% MeOH accelerated Trp and serotonin biosynthesis with induction of the corresponding genes. No other solvents including ethanol resulted in a Trp-inducing effect. This MeOH-induced Trp synthesis was positively regulated by abscisic acid but negatively regulated by cytokinin, suggesting hormonal involvement on the action of MeOH. Endogenous overproduction or suppression of MeOH either by PME1 overexpression or RNAi gene silencing revealed that PME1 overexpressing lines produced twofold higher Trp levels with elevated Trp biosynthetic gene expression, whereas RNAi lines showed twofold reduction in Trp level in healthy control rice leaves, suggesting that MeOH acts as an endogenous elicitor to enhance Trp biosynthesis. Among many transcription factors induced following MeOH treatment, the WRKY family showed significant induction patterns of which WRKY14 appeared to play a key regulatory role in MeOH-induced Trp and Trp-derived secondary metabolite biosynthesis.
Methanol is an endogenous elicitor molecule for the synthesis of tryptophan and tryptophan-derived secondary metabolites upon senescence of detached rice leaves.
Specimen part
View SamplesA specialized population of memory CD8+ T-cells resides in the epithelium of the respiratory tract to maintain protection against recurring infections. These cells express CD69 and the integrin 7 (CD103) and correspond to tissue resident memory T-cells (TRM) also described in intestine, liver and brain. A less well characterized population of CD103- CD8+ T-cells also resides in lungs and expresses markers characteristic of effector memory T-cells (TEM). We determined the transcriptional profiles of these memory CD8+ T-cell subsets retrieved from human lung resection samples and compared these with corresponding T-cell populations from peripheral blood of the same individuals. Our results demonstrate that each of the populations exhibits a distinct transcriptional identity. We found that the lung environment has a major impact on gene expression profiles. Thus, transcriptomes from CD103+ and CD103- subsets from lungs are much more resemblant to one another than to those from CD103+ or CD103- memory CD8+ T-cells from blood. TRM express specific sets of chemokine receptors, in accordance with their unique migratory properties. Furthermore, these cells constitutively express cytokine and cytotoxic genes for immediate effector function and chemokines to attract auxiliary immune cells. At the same time, multiple genes encoding inhibitory regulators are also expressed. This suggests that rapid ability to unleash effector functions is counterbalanced by programmed restraint, a combination that may be critical in the exposed but delicate tissue of the lung. Comprehensive sets of transcription factors were identified that characterize the memory CD8+ populations in the lungs. Prominent among these were components of the Notch pathway. Using mice genetically lacking expression of the NOTCH1 and NOTCH2 receptors in T-cells, we demonstrated that Notch controls both the number of lung TRM as well as the function of lung TEM. Our data illustrate the adaptation of lung resident T-cells to the requirements of the respiratory epithelial environment. Defining the molecular imprinting of these cells is important for rational vaccine design and may help to improve the properties of T-cells for adoptive cellular therapy.
Programs for the persistence, vigilance and control of human CD8<sup>+</sup> lung-resident memory T cells.
Specimen part, Subject
View SamplesTo uncover molecular mechanisms specifically involved in the pathogenesis of colitis-associated colon cancer (CAC), we studied tumorigenesis in experimental models of CAC and sporadic CRC that mimic characteristics of human CRC. Using comparative whole genome expression profiling, we observed differential expression of epiregulin (Ereg) in mouse models of colitis-associated, but not sporadic colorectal cancer. Similarly, highly significant upregulation of Ereg expression was found in cohorts of patients with colitis-associated cancer in inflammatory bowel disease but not in sporadic colorectal cancer. Furthermore, tumor-associated fibroblasts were identified as major source of Ereg in colitis-associated neoplasias. Functional studies showed that Ereg-deficient mice, although more prone to colitis, are strongly protected from colitis-associated tumors, and data from serial endoscopic studies revealed that Ereg promotes growth rather than initiation of tumors.
Tumor fibroblast-derived epiregulin promotes growth of colitis-associated neoplasms through ERK.
Sex, Specimen part
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