Regulation of transcription of the intracellular interleukin-1 receptor antagonist gene by AP-1 in mouse carcinoma cells

• Published in: Molecular carcinogenesis 2002-04, Vol.33 (4), p.237-243
• Main Authors: La, Eunhye, Rundhaug, Joyce E., Pavone, Amy, Fischer, Susan M.
• Format: Article
• Language: English
• Subjects: Animals; AP-1; Base Sequence; c-Fos protein; carcinoma cells; Carcinoma, Squamous Cell; Consensus Sequence; Gene Expression Regulation, Neoplastic - physiology; gene regulation; Genes, Reporter; Il-1Ra gene; interleukin 1 receptor antagonist; Interleukin 1 Receptor Antagonist Protein; Luciferases - genetics; Luciferases - metabolism; Mice; Recombinant Proteins - metabolism; Sequence Alignment; Sequence Deletion; Sialoglycoproteins - genetics; Skin Neoplasms; Transcription Factor AP-1 - metabolism; Transcription, Genetic - physiology; Transfection; Tumor Cells, Cultured
• ISSN: 0899-1987; 1098-2744
• DOI: 10.1002/mc.10042

Interleukin‐1 receptor antagonist (IL‐1Ra) is involved in many processes, including epidermal inflammation and hyperplasia after irritation or injury. However, the mechanism by which intracellular IL‐1Ra (icIL‐1Ra) expression is regulated in mouse keratinocytes has not been reported. We found that the CH72 mouse carcinoma cell line constitutively expresses the icIL‐1Ra mRNA. To study the transcriptional factors responsible for the constitutive expression of icIL‐1Ra, we functionally characterized 4.5 kb of the 5′ flanking region of the human icIL‐1Ra gene in these cells. We first demonstrated that icIL‐1Ra expression in these cells was regulated at the level of transcription. Deletion analysis of the promoter showed that regulatory elements for constitutive expression were located −158 to −49 bp upstream of the transcription start site for icIL‐1Ra. We investigated the cis‐ and trans‐acting factors required for icIL‐1Ra expression. An activating protein‐1 (AP‐1) site was identified as the positive regulatory element necessary for the constitutive expression of the icIL‐1Ra promoter in CH72 cells. Moreover, electrophoretic mobility shift assay and cotransfection experiments showed that c‐jun and c‐fos proteins bound to the AP‐1 site and functionally transactivated the icIL‐1Ra promoter in mouse carcinoma CH72 cells. © 2002 Wiley‐Liss, Inc.