IL-4 and IL-13 Induce SOCS-1 Gene Expression in A549 Cells by Three Functional STAT6-Binding Motifs Located Upstream of the Transcription Initiation Site
| Autor: | Gerhard Regl, Jutta Horejs-Hoeck, Angela Schmiedlechner, Petra Luft, Anna-Maria Frischauf, Albert Duschl, Fritz Aberger, Daniel Hebenstreit |
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| Rok vydání: | 2003 |
| Předmět: |
Amino Acid Motifs
Immunology Suppressor of Cytokine Signaling Proteins Biology Transfection Interferon-gamma Jurkat Cells Suppressor of Cytokine Signaling 1 Protein Th2 Cells Transcription (biology) Cell Line Tumor Gene expression Humans Immunology and Allergy Luciferase Promoter Regions Genetic Interleukin 4 Feedback Physiological Reporter gene Binding Sites Interleukin-13 Expression vector Intracellular Signaling Peptides and Proteins Molecular biology Up-Regulation Repressor Proteins Gene Expression Regulation Interleukin 13 Trans-Activators Interleukin-4 Transcription Initiation Site 5' Untranslated Regions Carrier Proteins STAT6 Transcription Factor Sequence motif Protein Binding Signal Transduction |
| Zdroj: | ResearcherID |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.171.11.5901 |
| Popis: | Proteins of the suppressors of cytokine signaling (SOCS) family have important functions as negative regulators of cytokine signaling. We show here that SOCS-1 expression can be induced in the human epithelial lung cell line A549 by IL-4 and IL-13. Analysis of reporter gene constructs under control of the SOCS-1 promoter provides evidence that IL-4- and IL-13-induced up-regulation is dependent on three IFN-γ-activated sequence motifs of the sequence TTC(N)4GAA, which is known for binding STAT6. The three motifs are situated close to each other ∼600 bp upstream of the transcriptional initiation site. When mutations were inserted into all three IFN-γ-activated sequence motifs at the same time, IL-4-IL-13-induced luciferase activity was abrogated. With single and double mutants, promoter activity was diminished in comparison with the wild-type promoter. STAT6 is therefore required for IL-4-IL-13-dependent SOCS-1 expression in A549 cells, and the three identified binding motifs cooperate to induce maximal transcription. EMSAs conducted with nuclear extracts of IL-4- and IL-13-stimulated A549 cells showed that STAT6 was able to bind to each of the three binding motifs. Finally, cotransfection of a SOCS-1 expression vector inhibited activation of SOCS-1 promoter luciferase constructs. Thus, SOCS-1 is able to autoregulate its expression via a negative feedback loop. |
| Databáze: | OpenAIRE |
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