A constitutive decay element promotes tumor necrosis factor alpha mRNA degradation via an AU-rich element-independent pathway.
Tumor necrosis factor alpha (TNF-alpha) expression is regulated by transcriptional as well as posttranscriptional mechanisms, the latter including the control of mRNA decay through an AU-rich element (ARE) in the 3' untranslated region (UTR). Using two mutant cell lines deficient for ARE-mediated mRNA decay, we provide evidence for a second element, the constitutive decay element (CDE), which is also located in the 3' UTR of TNF-alpha. In stably transfected RAW 264.7 macrophages stimulated with lipopolysaccharide (LPS), the CDE continues to target a reporter transcript for rapid decay, whereas ARE-mediated decay is blocked. Similarly, the activation of p38 kinase and phosphatidylinositol 3-kinase in NIH 3T3 cells inhibits ARE-mediated but not CDE-mediated mRNA decay. The CDE was mapped to an 80-nucleotide (nt) segment downstream of the ARE, and point mutation analysis identified within the CDE a conserved sequence of 15 nt that is required for decay activity. We propose that the CDE represses TNF-alpha expression by maintaining the mRNA short-lived, thereby preventing excessive induction of TNF-alpha after LPS stimulation. Thus, CDE-mediated mRNA decay is likely to be an important mechanism limiting LPS-induced pathologic processes.
Institute of Medical Microbiology, University of Basel, Petersplatz 10, CH-4003 Basel, Switzerland.
Georg
G
Stoecklin
Min
M
Lu
Bernd
B
Rattenbacher
Christoph
C
Moroni
D020413:3' Untranslated Regions; D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003609:Dactinomycin / Q000494:pharmacology; D017353:Gene Deletion; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008957:Models, Genetic; D008969:Molecular Sequence Data; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D017354:Point Mutation; D012333:RNA, Messenger / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases
D020413:3' Untranslated Regions; D008164:Luminescent Proteins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D049452:Green Fluorescent Proteins; D003609:Dactinomycin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D019869:Phosphatidylinositol 3-Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases