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.
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View SamplesBACKGROUND: Climate change will lead in the future to an occurrence of heat waves with a higher frequency and duration than observed today, which has the potential to cause severe damage to seedlings of temperate maize genotypes. In this study, we aimed to (I) assess phenotypic variation for heat tolerance of temperate European Flint and Dent maize inbred lines, (II) investigate the transcriptomic response of temperate maize to linearly increasing heat levels and, (III) identify genes associated with heat tolerance in a set of genotypes with contrasting heat tolerance behaviour. RESULTS: Strong phenotypic differences with respect to heat tolerance were observed between the examined maize inbred lines on a multi-trait level. We identified 607 heat responsive genes as well as 39 heat tolerance genes. CONCLUSION: Our findings indicate that individual inbred lines developed different genetic mechanisms in response to heat stress. We applied a novel statistical approach enabling the integration of multiple genotypes and stress levels in the analysis of abiotic stress expression studies. Overall design: Identifcation of differentially expressed genes between 8 genotypes and 3 heat levels
Genome-wide expression profiling and phenotypic evaluation of European maize inbreds at seedling stage in response to heat stress.
Specimen part, Subject
View SamplesThe oncofetal mRNA-binding protein IGF2BP1 and the transcriptional regulator SRF modulate gene expression in cancer. In cancer cells, we demonstrate that IGF2BP1 promotes the expression of SRF in a conserved and N6-methyladenosine (m6A) dependent manner by impairing the miRNA-directed decay of the SRF mRNA. This results in enhanced SRF-dependent transcriptional activity and promotes tumor cell growth and invasion. At the post-transcriptional level, IGF2BP1 sustains the expression of various SRF-target genes. The majority of these SRF/IGF2BP1-enhanced genes, including PDLIM7 and FOXK1, shows conserved upregulation with SRF and IGF2BP1 synthesis in cancer. PDLIM7 and FOXK1 promote tumor cell growth and were reported to enhance cell invasion. Consistently, 35 SRF/IGF2BP1-dependent genes showing conserved association with SRF and IGF2BP1 expression indicate a poor overall survival probability in ovarian, liver and lung cancer. In conclusion, these findings identify the SRF/IGF2BP1-, miRNome- and m6A-dependent control of gene expression as a conserved oncogenic driver network in cancer. Overall design: total RNA-Seq of Huh-7 cells transfected with either control siRNAs (siC) or siRNAs directed against IGF2BP1.
IGF2BP1 promotes SRF-dependent transcription in cancer in a m6A- and miRNA-dependent manner.
Cell line, Subject
View SamplesWe compared polyIC stimulated cells in the presence of either GFP or NS5 protein Overall design: A549 cells presence with GFP- or NS5-expressing plasmid using Polyjet (Signagen) according to manufacturer instructions, and 30 hours later stimulated with polyIC (Tocris) as previously described (Marazzi et al., 2012). At 12 hours post-stimulation, total cellular RNA was purified by RNeasy column (Qiagen).
Comparative Flavivirus-Host Protein Interaction Mapping Reveals Mechanisms of Dengue and Zika Virus Pathogenesis.
Specimen part, Cell line, Subject
View SamplesGene expression studies from hematopoietic stem cell (HSC) populations purified to variable degrees have defined a set of stemness genes. The present study describes the construction and comparative molecular analysis of l-phage cDNA libraries from highly purified primitive HSCs (PHSCs) which retained their long term repopulating activities (LTRAs), and from maturing HSCs (MHSCs) which were largely depleted of LTRAs. Library inserts were amplified and tagged by a T7 RNA polymerase promoter and used to generate biotinylated cRNA for Microarray hybridization. Microarray analysis of the libraries confirmed previous results but also revealed an unforseen preferential expression of translation and metabolism associated genes in the PHSCs. Therefore these data indicate that HSCs are quiescent only in regard of proliferative activities, but are in a state of readiness to provide the metabolic and translational activities required following induction of proliferation by factors which induce differentiation and exit from the HSC pool.
Gene expression profiles in murine hematopoietic stem cells revisited: analysis of cDNA libraries reveals high levels of translational and metabolic activities.
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View SamplesTo evaluate the effect of IGF2BPs on mRNA stability and gene expression output, we conducted RNA-seq in individual IGF2BP knockdown and control HepG2 cells with or without actinomycin D treatment. Our RNA-seq and RNA stability profiling revealed that IGF2BPs were involved in RNA stability regulation and contributed to the stabilization of the transcriptome. Overall design: HepG2 cells were infected with individual lentiviral IGF2BP shRNA and non-specific control (shNS), and selected by puromycin to generate stable knockdown lines. We treated HepG2 cells with actinomycin D to inhibit transcription and collected cells at indicated time points (i.e., 0h, 1h, 3h, 6h). The total RNA was extracted by miRNeasy Kit (Qiagen) and sequenced by Illumina. For IGF2BP-dependent gene expression, untreated cells (i.e., 0h samples) were sequenced in triplicate and analyzed. For RNA stability profiling, RNA half-life was calculated by comparing the gene expression at 1, 3, 6 hours with actinomycin treatment to that in un-treated samples, with two biological replicates for each group.
Recognition of RNA N<sup>6</sup>-methyladenosine by IGF2BP proteins enhances mRNA stability and translation.
Specimen part, Treatment, Subject, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
AML1-ETO requires enhanced C/D box snoRNA/RNP formation to induce self-renewal and leukaemia.
Specimen part, Disease
View SamplesMicroarray gene profilling indentified snoRNAs are downstream target of Amino Enhancer of Split (AES) and are essential for AML1-ETO9a induced leukemia.
AML1-ETO requires enhanced C/D box snoRNA/RNP formation to induce self-renewal and leukaemia.
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View SamplesGastric cancer is still one of the most common causes of cancer-related death worldwide, which is mainly attributable to late diagnosis and poor treatment options. Infection with H. pylori, different environmental factors and genetic alterations are known to influence the risk of developing gastric tumors. However, the molecular mechanisms involved in gastric carcinogenesis are still not fully understood, making it difficult to design targeted therapeutic approaches.
The stem cell factor SOX2 regulates the tumorigenic potential in human gastric cancer cells.
Specimen part, Cell line, Treatment, Time
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