Hopx appears to be needed for persistence of Th1 effector memory cells. IFN-gamma-producing Th cells are significantly reduced in Hopx-deficient mice compared to Hopx-expressing littermates and Hopx-deficient Th1 cells show a defective persistence upon adoptive transfer. Moreover, Hopx protects Th1 cells from Fas-mediated cell death in vitro. To further dissect the role of Hopx and to identify target genes of Hopx, we have performed transcriptome analysis to compare gene expression in Hopx-deficient versus Hopx-competent Th1 cells. In agreement with the role of Hopx in supporting survival of Th1 effector memory cells, anti-apoptotic cells were up-regulated and pro-apoptotic genes were down-regulated in Hopx-competent compared to Hopx-deficient Th1 cells.
Persistence of effector memory Th1 cells is regulated by Hopx.
Sex, Specimen part
View SamplesIL-22 acts on epithelial cells and has been shown to induce tissue protective and wound healing responses in these cells. But it has recently been decribed that IL-22 exacerbates ileatis after infection with T. gondii.
Interleukin-22 induces interleukin-18 expression from epithelial cells during intestinal infection.
Specimen part, Time
View SamplesRegulation of mRNA stability by RNA-protein interactions contributes significantly to quantitative aspects of gene expression. We have identified potential mRNA targets of the AU-rich element binding protein AUF1. Myc-tagged AUF1 p42 was induced in mouse NIH-3T3 cells and RNA-protein complexes isolated using anti-myc tag antibody beads. Bound mRNAs were analyzed with Affymetrix microarrays. We have identified 508 potential target mRNAs that were at least 3-fold enriched compared to control cells without myc-AUF1. 22.3% of the enriched mRNAs had an AU-rich cluster in the ARED Organism database, against 16.3% of non-enriched control mRNAs. The enrichment towards AU-rich elements was also visible by AREScore with an average value of 5.2 in the enriched mRNAs versus 4.2 in the control group. Yet, many mRNAs were enriched without a high ARE score suggesting that AUF1 has a broader binding spectrum than standard AUUUA repeats. AUF1 did not preferentially bind to unstable mRNAs. Still, some enriched mRNAs were highly unstable, as those of TNFSF11 (known as RANKL), KLF10, HES1, CCNT2, SMAD6, and BCL6. We have mapped some of the instability determinants. HES1 mRNA appeared to have a coding region determinant. Detailed analysis of the RANKL and BCL6 3UTR revealed for both that full instability required two elements, which are conserved in evolution. In RANKL mRNA both elements are AU-rich and separated by 30 bases, while in BCL6 mRNA one is AU-rich and 60 bases from a non AU-rich element that potentially forms a stem-loop structure.
Short-lived AUF1 p42-binding mRNAs of RANKL and BCL6 have two distinct instability elements each.
Cell line
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