Posttranscriptional regulation of IL-10 gene expression through sequences in the 3'-untranslated region.
IL-10 is an 18-kDa immunoregulatory cytokine the transcription of which is controlled by the ubiquitously expressed transcription factors Sp1 and Sp3. Although many cell types express IL-10 mRNA, not all make detectable amounts of protein, and levels of protein expression vary enormously. We show here that much of this variation can be accounted for by posttranscriptional mechanisms. Multiple copies of potential mRNA destabilizing motifs AUUUA and related sequences can be found to the 3'-untranslated region (UTR) of IL-10 mRNA distributed through three potential regulatory regions. Evidence of RNA-destabilizing activities in all three regions was deduced from luciferase reporter assays. The half-life of RNA containing the 3'-UTR of IL-10 mRNA was quite short in both nonstimulated (t1/2 = 1 h), and PMA-stimulated EL-4 cell (t1/2 = 3 h). In contrast, the half-life of RNA lacking the 3'-UTR was much longer (t1/2 = >12 h) whether cells were stimulated or not. This suggests that many cells are poised to secrete IL-10 and will do so if they receive appropriate posttranscriptional signals.
Powell
M J
MJ
Sir William Dunn School of Pathology, University of Oxford, United Kingdom. mtone@molbiol.ox.ac.uk
Thompson
S A
SA
Tone
Y
Y
Waldmann
H
H
Tone
M
M
D020413:3' Untranslated Regions / Q000276:immunology*; D000818:Animals; D019677:Artificial Gene Fusion; D001483:Base Sequence; D002460:Cell Line; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology*; D006207:Half-Life; D006801:Humans; D007127:Immunoglobulin Constant Regions / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D016753:Interleukin-10 / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000276:immunology*; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D019076:Transgenes / Q000276:immunology
D020413:3' Untranslated Regions; D007127:Immunoglobulin Constant Regions; D007143:Immunoglobulin Heavy Chains; D012333:RNA, Messenger; D016753:Interleukin-10; D013755:Tetradecanoylphorbol Acetate