The proximal region of the 3'-untranslated region of cyclooxygenase-2 is recognized by a multimeric protein complex containing HuR, TIA-1, TIAR, and the heterogeneous nuclear ribonucleoprotein U.
Cyclooxygenase-2 (COX-2) is an early response gene induced in renal mesangial cells by interleukin-1beta (IL-1beta). The 3'-untranslated region (3'-UTR) of COX-2 mRNA plays an important role in IL-1beta induction by regulating message stability and translational efficiency. The first 60 nucleotides of the 3'-UTR of COX-2 are highly conserved and contain multiple copies of the regulatory sequence AUUUA. Introduction of the 60-nucleotide sequence into the 3'-UTR of a heterologous reporter gene resulted in a 70% decrease in reporter gene expression. Electrophoretic mobility shift assays (EMSAs) demonstrated that mesangial cell nuclear fractions contain a multimeric protein complex that bound this region of COX-2 mRNA in a sequence-specific manner. We identified four members of the protein-RNA complex as HuR, TIA-1, TIAR, and the heterogeneous nuclear ribonucleoprotein U (hnRNP U). Treatment of mesangial cells with IL-1beta caused an increase in cytosolic HuR, which was accompanied by an increase in COX-2 mRNA that co-immunoprecipitated with cytosolic HuR. Therefore, we propose that HuR binds to the proximal region of the 3'-UTR of COX-2 following stimulation by IL-1beta and increases the expression of COX-2 mRNA by facilitating its transport out of the nucleus.
Cok
Steven J
SJ
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Acton
Stephen J
SJ
Morrison
Aubrey R
AR
D020413:3' Untranslated Regions; D000818:Animals; D000954:Antigens, Surface; D001483:Base Sequence; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D003600:Cytosol / Q000378:metabolism; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; D004591:Electrophoresis, Polyacrylamide Gel; D017930:Genes, Reporter; D034722:Heterogeneous-Nuclear Ribonucleoprotein U / Q000378:metabolism; D007375:Interleukin-1 / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics* / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013347:Subcellular Fractions / Q000378:metabolism; D000074019:T-Cell Intracellular Antigen-1; D013997:Time Factors; D014162:Transfection
D020413:3' Untranslated Regions; D000954:Antigens, Surface; D051959:ELAV Proteins; D000067780:ELAV-Like Protein 1; C098770:ELAVL1 protein, human; D034722:Heterogeneous-Nuclear Ribonucleoprotein U; D007375:Interleukin-1; D007527:Isoenzymes; D008565:Membrane Proteins; D011506:Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D000074019:T-Cell Intracellular Antigen-1; C499367:Tia1 protein, mouse; C489665:Tial1 protein, mouse; C489666:Tial1 protein, rat; D008156:Luciferases; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases