Transcriptional regulation of intracellular IL-1 receptor antagonist gene by IL-1 alpha in primary mouse keratinocytes.
The inflammatory cytokine IL-1alpha mediates inflammatory reactions in skin and up-regulates the expression of other proinflammatory genes. We previously found that IL-1alpha also increases steady state mRNA levels for intracellular IL-1 receptor antagonist (icIL-1Ra) in primary mouse keratinocytes; however, the mechanism for this was unknown. Here we show that increased expression in primary keratinocytes is due to increased rates of transcription. To study the transcriptional regulation of icIL-1Ra expression induced by IL-1alpha, we functionally characterized 4.5 kb of the 5'-flanking region of the human icIL-1Ra gene. Deletion analysis showed that regulatory elements were contained in the -598- and -288-bp region upstream of the transcription start site. Then we investigated cis- and trans-acting factors required for icIL-1Ra expression and found that a NF-IL-6 site and a NF-kappaB site in the icIL-1Ra promoter were responsible for IL-1alpha-induced icIL-1Ra expression. Moreover, gel shift assays and cotransfection experiments showed that CCAAT/enhancer-binding proteins alpha, beta, and p65 bind to the NF-IL-6 site and NF-kappaB site, respectively, and functionally trans-activate the icIL-1Ra promoter. Finally, mutational analysis confirmed that these elements were both essential for maximal transcription induced by IL-1alpha.
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Department of Carcinogenesis, University of Texas M. D. Anderson Cancer Center, Science Park-Research Division, Smithville, TX 78957, USA.
Fischer
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D000818:Animals; D051743:CCAAT-Enhancer-Binding Protein-delta; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D002478:Cells, Cultured; D004252:DNA Mutational Analysis; D005786:Gene Expression Regulation / Q000276:immunology*; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000378:metabolism / Q000502:physiology*; D007424:Intracellular Fluid / Q000276:immunology / Q000378:metabolism; D015603:Keratinocytes / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000276:immunology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors*; D012795:Sialoglycoproteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000502:physiology; D051996:Transcription Factor RelA; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000276:immunology*; D014162:Transfection
D022762:CCAAT-Enhancer-Binding Proteins; C497252:CEBPD protein, human; C497253:Cebpd protein, mouse; C507763:IL1RN protein, human; C507764:Il1rn protein, mouse; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D016328:NF-kappa B; D020033:Protein Isoforms; D017472:Receptors, Interleukin-1; D012795:Sialoglycoproteins; D015534:Trans-Activators; D051996:Transcription Factor RelA; D014157:Transcription Factors; D051743:CCAAT-Enhancer-Binding Protein-delta