Discriminating pathogenic bacteria from energy-harvesting commensals is key to host immunity. Using mutants defective in the enzymes of O-linked N-acetylglucosamine (O-GlcNAc) cycling, we examined the role of this nutrient-sensing pathway in the Caenorhabidits elegans innate immune response. Using whole genome transcriptional profiling, O-GlcNAc cycling mutants exhibited deregulation of unique stress- and immune-responsive genes as well as genes shared with the p38 MAPK/PMK-1 pathway. Moreover, genetic analysis showed that deletion of O-GlcNAc transferase (ogt-1) yielded animals hypersensitive to the human pathogen S. aureus but not to P. aeruginosa. Genetic interaction studies further revealed that nutrient-responsive OGT-1 acts through the conserved -catenin (BAR-1) pathway and in concert with p38 MAPK/PMK-1 to modulate the immune response to S. aureus. The participation of the nutrient sensor O-GlcNAc transferase in an immunity module conserved from C. elegans to humans reveals an unexplored nexus between nutrient availability and a pathogen-specific immune response.
Conserved nutrient sensor O-GlcNAc transferase is integral to C. elegans pathogen-specific immunity.
Treatment
View SamplesNutrient-responsive oogenesis in Drosophila is a complex and dynamic process regulated, in part, by members of the Pc and Trx complexes. The recent finding that O-GlcNAc Transferase (ogt/sxc) is essential for Pc repression raises the question of whether this nutrient-sensing pathway plays a role in regulating oogenesis. OGT transfers O-GlcNAc to key transcriptional regulators in response to graded levels of the nutrient-derived precursor UDP-GlcNAc; O-GlcNAcase (OGA) catalyzes the removal of O-GlcNAc. Here we produced a null allele of oga (oga1) in Drosophila to examine its in vivo function. We found that oga mutant flies were viable, but that females displayed greatly reduced fecundity. The ovaries from the female OGA knockout exhibited a starvation-like phenotype, even under well-fed conditions. Germline stem cell division was slowed in the germarium of OGA knockout fly ovarioles. Ovaries from the oga1 mutants displayed significantly decreased H3K4 monomethylation in germline stem cells. The Trithorax family members Trx and Ash1 and Compass member Set1 histone methyltransferases are O-GlcNAc modified in oga1 mutant ovaries. Our results suggest that the loss of OGA disrupts oogenesis at least in part by interfering with H3K4 monomethylation in germ cells in the ovary. The findings also suggest that O-GlcNAc cycling is an essential part of the nutrient-responsive epigenetic machinery regulating Drosophila oogenesis in response to a changing nutrient supply.
Drosophila O-GlcNAcase Deletion Globally Perturbs Chromatin O-GlcNAcylation.
No sample metadata fields
View SamplesSingle O-GlcNAc modification orchestrate by O-GlcNAc Transferase (OGT) and O-GlcNAcase (OGA alias MGEA5) enzymes, affects signal transduction and gene expression by chromatin modulation. We developed Oga deleted MEF (mouse embryonic fibroblast) cells to investigate effects of O-GlcNAc modification in mice. RNA isolated from Mouse Embryonic Fibroblast cells generated from Oga Knock out (KO) Heterozygous (Het) and wild type (WT) cells and subjected to microarray analysis.
Conditional knock-out reveals a requirement for O-linked N-Acetylglucosaminase (O-GlcNAcase) in metabolic homeostasis.
Sex, Specimen part
View SamplesTHO2 and HPR1 proteins were co-depleted from Drosophila S2 cells and their role in mRNA export analysed by comparing total RNA and cytoplasmic RNA
The superhelical TPR-repeat domain of O-linked GlcNAc transferase exhibits structural similarities to importin alpha.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Dynamic O-GlcNAc cycling at promoters of Caenorhabditis elegans genes regulating longevity, stress, and immunity.
No sample metadata fields
View SamplesNutrient-driven O-GlcNAcylation of key components of the transcription machinery may epigenetically modulate gene expression in metazoans. Knockouts of the O-GlcNAc cycling enzymes in C. elegans are viable and fertile, allowing a global analysis of the impact of GlcNAcylation.
Dynamic O-GlcNAc cycling at promoters of Caenorhabditis elegans genes regulating longevity, stress, and immunity.
No sample metadata fields
View SamplesNutrient-driven O-GlcNAcylation of key components of the transcription machinery may epigenetically modulate gene expression in metazoans. Knockouts of the O-GlcNAc cycling enzymes in C. elegans are viable and fertile, allowing a global analysis of the impact of GlcNAcylation.
Dynamic O-GlcNAc cycling at promoters of Caenorhabditis elegans genes regulating longevity, stress, and immunity.
No sample metadata fields
View SamplesNutrient-driven O-GlcNAcylation of key components of the transcription machinery may epigenetically modulate gene expression in metazoans. Knockouts of the O-GlcNAc cycling enzymes in C. elegans are viable and fertile, allowing a global analysis of the impact of GlcNAcylation. Here we compare gene expression in wild type and O-GlcNAc mutants (ogt-1 and oga-1) in synchronized, fed L1 animals.
Dynamic O-GlcNAc cycling at promoters of Caenorhabditis elegans genes regulating longevity, stress, and immunity.
No sample metadata fields
View SamplesWe report the effect of DKK1 treatment during culture on the length and transcriptome of embryos on day 15 of development, supporting the notion that changes early in development affect later stages of development. Overall design: Bovine embryos were produced in vitro and exposed to either 0 or 100 ng/ml DKK1 from day 5 to 7 of culture. Embryos were transferred on day 7 and recovered on day 15 for evaluation of length and transciptome
Dickkopf-related protein 1 is a progestomedin acting on the bovine embryo during the morula-to-blastocyst transition to program trophoblast elongation.
Treatment, Subject
View SamplesBackground & Aims: Ursodeoxycholic acid (UDCA) attenuates chemical and colitis-induced colon carcinogenesis in animal models. We investigated its mechanism of action on normal intestinal cells, in which carcinogenesis- or inflammation-related alterations do not interfere with the result. Methods: Alterations of gene expression were identified in Affymetrix arrays in isolated colon epithelium of mice fed with a diet containing 0.4% UDCA and were confirmed in the normal rat intestinal cell line IEC-6 by RT-PCR. The effect of the insulin receptor substrate 1 (Irs-1) expression and of ERK phosphorylation on proliferation was investigated in vitro by flow cytometry, western blotting, siRNA-mediated gene suppression or by pharmacological inhibition of the kinase activity. The ERK1-effect on Irs-1 transcription was tested in a reporter system. Results: UDCA-treatment in vivo suppressed potential pro-proliferatory genes including Irs-1 and reduced cell proliferation by more than 30%. In vitro it neutralised the proliferatory signals of IGF-1 and EGF and slowed down the cell cycle. Irs-1 transcription was suppressed due to high ERK1 activation. Both Irs-1 suppression and the persistent high ERK activation inhibited proliferation. Conversely, the decrease of phosphorylation of ERK1 (but not ERK2) or of its expression partially abrogated the inhibitory effects of UDCA. Conclusions: UDCA inhibits proliferation of intestinal epithelial cells by acting upon IGF-1 and EGF pathways and targeting ERK1 and, consequently, Irs-1. The inhibition of these pathways adds a new dimension to the physiological and therapeutic action of UDCA and, since both pathways are activated in inflammation and cancer, suggests new applications of UDCA in chemoprevention and chemotherapy.
UDCA slows down intestinal cell proliferation by inducing high and sustained ERK phosphorylation.
Specimen part, Cell line
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