Differential regulation of ARE-mediated TNFalpha and IL-1beta mRNA stability by lipopolysaccharide in RAW264.7 cells.
Messenger RNA degradation is a mechanism by which eukaryotic cells regulate gene expression and influence cell growth and differentiation. Many protooncogene, cytokine, and growth factor RNAs contain AU-rich element (AREs) in the 3'untranslated regions which enable them to be targeted for rapid degradation. To investigate the mechanism of ARE-mediated RNA stability, we demonstrate the expression and regulation of TNFalpha and IL-1beta mRNAs in LPS-stimulated macrophages. TNFalpha mRNA was rapidly induced by LPS and showed short half-life at 2-h induction, whereas IL-1beta mRNA was induced slowly and had longer half-life. Electrophoretic mobility shift assays showed that the LPS-induced destabilization factor tristetraprolin (TTP) could bind to TNFalpha ARE with higher affinity than to IL-1beta ARE. HuR was identified to interact with TNFalpha ARE to exert RNA stabilization activity. The expression and phosphorylation of TTP could be activated by p38 MAPK pathway during LPS stimulation. Moreover, ectopic expression with TTP and kinases in p38 pathway followed by biochemical assays showed that the activation of p38 pathway resulted in the phosphorylation of TTP and a decrease in its RNA-binding activity. The ARE-containing reporter assay presented that the p38 signal could reverse the inhibitory activity of TTP on IL-1beta ARE but not on TNFalpha ARE. The present results indicate that the heterogeneity of AREs from TNFalpha and IL-1beta could reflect distinct ARE-binding proteins to modulate their RNA expression.
Chen
Yu-Ling
YL
Graduate Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan.
Huang
Ya-Lin
YL
Lin
Nien-Yi
NY
Chen
Hui-Chen
HC
Chiu
Wan-Chih
WC
Chang
Ching-Jin
CJ
D000818:Animals; D000954:Antigens, Surface / Q000378:metabolism; D001483:Base Sequence; D002460:Cell Line; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D005786:Gene Expression Regulation; D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism; D015398:Signal Transduction; D051816:Tristetraprolin / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology
D000954:Antigens, Surface; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; C000630986:HNRNPD protein, human; D000081035:Heterogeneous Nuclear Ribonucleoprotein D0; D034502:Heterogeneous-Nuclear Ribonucleoprotein D; C000630987:Hnrpd protein, mouse; D007375:Interleukin-1; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D051816:Tristetraprolin; D014409:Tumor Necrosis Factor-alpha; D048051:p38 Mitogen-Activated Protein Kinases