The Ca2+/calmodulin-activated, phosphoprotein phosphatase calcineurin is sufficient for positive transcriptional regulation of the mouse IL-4 gene
| Autor: | Masato Kubo, Randall L. Kincaid, David R. Webb, John Ransom |
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| Rok vydání: | 1994 |
| Předmět: |
Transcription
Genetic Molecular Sequence Data Immunology Phosphatase Regulatory Sequences Nucleic Acid Biology Mice Calmodulin Phosphoprotein Phosphatases Tumor Cells Cultured Transcriptional regulation Animals Immunology and Allergy Electrophoretic mobility shift assay Nuclear protein Gene Base Sequence Calcineurin Binding protein General Medicine Molecular biology Gene Expression Regulation Regulatory sequence Calcium Calmodulin-Binding Proteins Interleukin-4 Signal transduction Signal Transduction |
| Zdroj: | International Immunology. 6:179-188 |
| ISSN: | 1460-2377 0953-8178 |
| DOI: | 10.1093/intimm/6.2.179 |
| Popis: | We have studied the TCR mediated signal transduction pathways involved in transcriptional regulation of the mouse IL-4 gene. The sequences extending from base pair -766 to +63 of the IL-4 gene were inserted upstream of a luciferase indicator gene. Transcriptional activity was observed when the construct, [pIL-4(-766)], was transfected into either the IL-4 producing cell line, EL-4, or the IL-4 non-producing T cell hybridoma, 68-41, but not in the L929 fibroblast cell line. By analysis of deletion mutants of pIL-4(-766), we identified a transcriptional regulatory element that is tightly associated with a signal coming from the TCR and which controls inducible activation of the IL-4 promoter. By analysis of deletion mutants of pIL-4(-766), this latter element was found between base pairs -147 to -17. Electrophoretic mobility shift assays indicated that expression of a nuclear binding protein with binding sites between base pairs -84 and -55 could be induced. By competition and mutation analysis, the binding motif of this protein was determined to be AAAATTTTCC. Stimulation with ionomycin alone was sufficient to induce activity in pIL-4(-766). Cyclosporin A inhibited both the IL-4 promoter activity and activation of the inducible nuclear protein. Transient over-expression of a constitutively active form of the Ca2+/calmodulin-regulated protein phosphatase, calcineurin was sufficient to cause activation of pIL-4(-766) without any additional stimulus. These results indicate that the signaling requirements for activation of upstream positive regulatory elements of the IL-4 gene are distinct from those of the IL-2 gene. Ca2+ mobilization is sufficient to activate the IL-4 promoter, whereas IL-2 gene transcription requires both Ca2+ mobilization and protein kinase C activation. |
| Databáze: | OpenAIRE |
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