Quorum sensing (QS) is a mechanism of bacterial gene regulation in response to increases in population density. Production of small molecule QS signals, their accumulation within a diffusion-limited environment and their binding to the LuxR-type receptor trigger QS-controlled gene regulatory cascades. QS pathways mediated by acylhomoserine lactones (AHLs) in Gram-negative bacteria are the best studied. In Pseudomonas aeruginosa, for example, binding of AHLs to their cognate receptors (LasR, RhlR) controls production of virulence factors, pigments, antibiotics and other behaviors important for its interactions with eukaryotic hosts and other bacteria. We isolated a new small cyclopropane-containing fatty acid, lyngbyoic acid (1), as a major metabolite of the marine cyanobacterium, Lyngbya sp., collected off Fort Pierce, Florida. The structure of 1 was determined by NMR, MS and optical rotation. We screened 1 against four reporters based on AHL receptors from Vibrio fischeri (LuxR), Aeromonas hydrophila (AhyR), Agrobacterium tumefaciens (TraR) and P. aeruginosa (LasR) and found that 1 most strongly affected LasR. We show, by using a defined set of reporters, that compound 1 acts both through the AHL-binding site of LasR and independent of it. We also show that 1 reduces pyocyanin and LasB, both on the protein and transcript level, in wild-type P. aeruginosa, and that 1 directly inhibits LasB enzymatic activity. Conversely, dodecanoic acid (11) increased pyocanin and LasB, demonstrating that 1 is a tagged fatty acid potentially resistant to -oxidation.
Lyngbyoic acid, a "tagged" fatty acid from a marine cyanobacterium, disrupts quorum sensing in Pseudomonas aeruginosa.
No sample metadata fields
View SamplesMicroRNAs (miRNAs) are small RNAs that play important regulatory roles in many cellular pathways. MiRNAs associate with members of the Argonaute (Ago) protein family and bind to partially complementary sequences on mRNAs and induce translational repression or mRNA decay. MiRNA expression can be controlled by transcription factors and can therefore be cell type- or tissue-specific. Here we have analyzed miRNA expression profiles in murine monocyte-derived dendritic cells (DCs) and macrophages upon stimulation with LPS, LDL, eLDL and oxLDL to identify not only stimuli-specific miRNA, but also to identify a hierarchical miRNA system involving miR-155. For this, miR-155 knockout dendritic cells and macrophages were also sequenced using the same stimuli. Overall design: Sequencing of murine monocyte-derived dendritic cells and macrophages (each wild type and miR-155 knock out cells) matured and stimulated, respectively, by LPS, oxLDL, eLDL or LDL.
A miR-155-dependent microRNA hierarchy in dendritic cell maturation and macrophage activation.
Specimen part, Cell line, Subject
View SamplesType I IFN-signaling suppresses an excessive IFN-{gamma} response and prevents lung damage and chronic inflammation following Pneumocystis (PC)-infection and clearance in CD4 T cell-competent mice.
Type-I IFN signaling suppresses an excessive IFN-gamma response and thus prevents lung damage and chronic inflammation during Pneumocystis (PC) clearance in CD4 T cell-competent mice.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The mammalian TRIM-NHL protein TRIM71/LIN-41 is a repressor of mRNA function.
Specimen part, Cell line
View SamplesWe identify mammalian TRIM71 as repressor of mRNAs that inhibits translation and affects mRNA stability.
The mammalian TRIM-NHL protein TRIM71/LIN-41 is a repressor of mRNA function.
Cell line
View SamplesmicroRNAs (miRNAs) are small non-coding RNAs that function in literally all cellular processes. miRNAs interact with Argonaute (Ago) proteins and guide them to specific target sites located in the 3’ untranslated region (UTR) of target mRNAs leading to translational repression and deadenylation-induced mRNA degradation. Most miRNAs are processed from hairpin-structured precursors by the consecutive action of the RNase III enzymes Drosha and Dicer. However, processing of miR-451 is Dicer-independent and cleavage is mediated by the endonuclease Ago2. Here we have characterized miR-451 sequence and structure requirements for processing as well as sorting of miRNAs into different Ago proteins. Pre-miR-451 appears to be optimized for Ago2 cleavage and changes result in reduced processing. In addition, we show that the mature miR-451 only associates with Ago2 suggesting that mature miRNAs are not exchanged between different members of the Ago protein family. Based on cloning and deep sequencing of endogenous miRNAs associated with Ago1-3, we do not find evidence for miRNA sorting in human cells. However, Ago identity appears to influence the length of some miRNAs, while others remain unaffected. Overall design: Examination of miRNAs associated with endogenous human Ago1-4 in HeLa cells
microRNAs associated with the different human Argonaute proteins.
No sample metadata fields
View SamplesWe identify mammalian TRIM71 as repressor of mRNAs that inhibits translation and affects mRNA stability. In this data set we compare the expression profile of mouse ES upon Trim71 KD versus that of the parental cells.
The mammalian TRIM-NHL protein TRIM71/LIN-41 is a repressor of mRNA function.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Reprogramming factor expression initiates widespread targeted chromatin remodeling.
Specimen part
View SamplesDespite rapid progress in characterizing transcription factor-driven reprogramming of somatic cells to an induced pluripotent stem (iPS) cell state, many mechanistic questions still remain. To gain insight into the earliest events in the reprogramming process, we systematically analyzed the transcriptional and epigenetic changes that occur during early factor induction after discrete numbers of divisions. We observed rapid, genome-wide changes in the euchromatic histone modification, H3K4me2, at more than a thousand loci including large subsets of pluripotency or developmentally related gene promoters and enhancers. In contrast, patterns of the repressive H3K27me3 modification remained largely unchanged except for focused depletion specifically at positions where H3K4 methylation is gained. These chromatin regulatory events precede transcriptional changes within the corresponding loci. Our data provide evidence for an early, organized, and population-wide epigenetic response to ectopic reprogramming factors that clarify the temporal order through which somatic identity is reset during reprogramming.
Reprogramming factor expression initiates widespread targeted chromatin remodeling.
Specimen part
View SamplesThe S1 and S3 erythroid developmental subsets were isolated using flow cytometry and the cell surface markers CD71 and Ter119 as described by Pop et. al. 2010 (PMID: 20877475)
Global DNA demethylation during mouse erythropoiesis in vivo.
Specimen part
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