Project description:We investigated the role of mTORC1 in murine hematopoiesis by conditionally deleting the Raptor gene in murine hematopoietic stem cells. We observed mutliple alterations evoked by Raptor loss in hematopoiesis and profiled gene-expression alterations induced by raptor loss in Flt3-Lin-Sca1+cKit+ hematopoietic stem and progenitor enriched cell populations, 5 weeks post Raptor deletion. Flt3-Lin-Sca1+cKit+ cells were flow sorted from mice containing homozygous floxed alleles for exon 6 of the Raptor gene in the presence (MT group) or absence (WT group) of the MxCre transgene, which was induced with injections of mice with pIpC 5 weeks before cell isolation.
Project description:Naïve T cells respond to antigen stimulation by exiting from quiescence into clonal expansion and functional differentiation, but the control mechanism is elusive. Here we describe that Raptor/mTORC1-dependent metabolic reprogramming is a central determinant of this transitional process. Loss of Raptor abrogates T cell priming and Th2 cell differentiation, although Raptor function is less important for continuous proliferation of actively cycling cells. mTORC1 coordinates multiple metabolic programs in T cells including glycolysis, lipid synthesis and oxidative phosphorylation to mediate antigen-triggered exit from quiescence. mTORC1 further links glucose metabolism to the initiation of Th2 differentiation by orchestrating cytokine receptor expression and cytokine responsiveness. Activation of Raptor/mTORC1 integrates T cell receptor (TCR) and CD28 co-stimulatory signals in antigen-stimulated T cells. Our studies identify a Raptor/mTORC1-dependent pathway linking signal-dependent metabolic reprogramming to quiescence exit, and this in turn coordinates lymphocyte activation and fate decisions in adaptive immunity. We used microarrays to explore the gene expression profiles differentially expressed in CD4+ T-cells from wild-type (WT) and CD4(cre) x Raptor(fl/fl) mice before and after stimulation with anti CD3/CD28 antibodies.
Project description:We investigated the role of mTORC1 in murine hematopoiesis by conditionally deleting the Raptor gene in murine hematopoietic stem cells. We observed mutliple alterations evoked by Raptor loss in hematopoiesis and profiled gene-expression alterations induced by raptor loss in Flt3-Lin-Sca1+cKit+ hematopoietic stem and progenitor enriched cell populations, 5 weeks post Raptor deletion.
Project description:Analyses of new genomic, transcriptomic or proteomic data commonly result in trashing many unidentified data escaping the ‘canonical’ DNA-RNA-protein scheme. Testing systematic exchanges of nucleotides over long stretches produces inversed RNA pieces (here named “swinger” RNA) differing from their template DNA. These may explain some trashed data. Here analyses of genomic, transcriptomic and proteomic data of the pathogenic Tropheryma whipplei according to canonical genomic, transcriptomic and translational 'rules' resulted in trashing 58.9% of DNA, 37.7% RNA and about 85% of mass spectra (corresponding to peptides). In the trash, we found numerous DNA/RNA fragments compatible with “swinger” polymerization. Genomic sequences covered by «swinger» DNA and RNA are 3X more frequent than expected by chance and explained 12.4 and 20.8% of the rejected DNA and RNA sequences, respectively. As for peptides, several match with “swinger” RNAs, including some chimera, translated from both regular, and «swinger» transcripts, notably for ribosomal RNAs. Congruence of DNA, RNA and peptides resulting from the same swinging process suggest that systematic nucleotide exchanges increase coding potential, and may add to evolutionary diversification of bacterial populations.