STAT3 participates in transcriptional activation of the C-reactive protein gene by interleukin-6.
Interleukin-6 (IL-6) is the major cytokine inducing transcription of human C-reactive protein (CRP) during the acute phase response. STAT (signal transducers and activators of transcription) family members, recently shown to be important mediators of the effects of many cytokines including IL-6, generally induce their effects by binding to palindromic sequences with TT(N)5AA motifs. We report an IL-6 responsive element in the proximal region of the human CRP 5'-flanking region that bears a TT(N)4AA motif, which we have termed CRP acute phase response element (CRP-APRE). In Hep3B cells, IL-6 but not interferon-gamma was capable of activating CAT constructs driven by the CRP promoter containing CRP-APRE. Overexpressed STAT3 was able to transactivate CRP-chloramphenicol acetyltransferase constructs through the CRP-APRE and was able to enhance endogenous CRP mRNA accumulation in response to IL-6. STAT3 (or an antigenically related molecule) bound to the CRP-APRE in response to IL-6. Overexpression of STAT3 in the presence of IL-6 was capable of inducing expression of a construct consisting of the CRP-APRE and a minimal thymidine kinase promoter lacking a C/EBP site. Taken together, these findings indicate that STAT3 participates in the transcriptional activation of CRP in response to IL-6.
Zhang
D
D
Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA.
Sun
M
M
Samols
D
D
Kushner
I
I
D000209:Acute-Phase Proteins / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015152:Blotting, Northern; D002097:C-Reactive Protein / Q000096:biosynthesis* / Q000235:genetics*; D006528:Carcinoma, Hepatocellular; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D008113:Liver Neoplasms; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D050796:STAT3 Transcription Factor; D017384:Sequence Deletion; D012689:Sequence Homology, Nucleic Acid; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured
D000209:Acute-Phase Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; D007375:Interleukin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C494088:Stat3 protein, rat; D015534:Trans-Activators; D007371:Interferon-gamma; D002097:C-Reactive Protein