Molecular cloning and identification of the human interleukin 13 alpha 2 receptor (IL-13Ra2) promoter.
The interleukin 13 alpha 2 receptor (IL-13Ra2) has been shown to be expressed in most malignant glioblastoma cells. Recent studies suggest that IL-13Ra2 serves as a dominant negative inhibitor or a decoy receptor for IL-13. To investigate the transcriptional regulation of this receptor, we cloned and characterized the promoter for the human IL-13Ra2 gene. Our results demonstrate that this promoter contains three TATA boxes and one CCAAT site. Several putative transcriptional factor binding sites for nuclear factor of activated T cells 1, AP1 (c-JUN and c-FOS), AP2, GABP, OCT1, GATA3, PRE, and C-ETS1 were predicted in the promoter region. Using the secreted alkaline phosphate reporter gene assay, we investigated the functional activity of the human IL-13Ra2 promoter by transient transfection in glioma cell lines U118, U87, and T98, which differ in their expression of the human IL-13Ra2 protein. The different secreted alkaline phosphate activities among these 3 cell lines suggest that the expression of human IL-13Ra2 is regulated at the transcriptional level. Methylation analysis showed that expression of IL-13Ra2 may not be the result of methylation of the CpG dinucleotides in the promoter region of the gene. Deletion analysis identified a 64 base pair (bp) region that is necessary for human IL-13Ra2 promoter activity. This 64-bp sequence contains cis-elements for AP1, nuclear factor of activated T cells, and AP2. The possible role of AP1 in the regulation of human IL-13Ra2 promoter activity was suggested by in vitro mutagenesis and c-JUN N-terminal kinase inhibition analysis.
Wu
An-Hua
AH
Department of Neurosurgery, University of Minnesota Medical School, 2001 Sixth Street SE, Minneapolis, MN 55455, USA.
Low
Walter C
WC
D001483:Base Sequence / Q000235:genetics; D003001:Cloning, Molecular / Q000379:methods; D019175:DNA Methylation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015723:Gene Library; D005910:Glioma / Q000235:genetics / Q000378:metabolism; D006801:Humans; D053661:Interleukin-13 Receptor alpha1 Subunit; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D018123:Receptors, Interleukin / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics*; D053660:Receptors, Interleukin-13; D014407:Tumor Cells, Cultured
D004791:Enzyme Inhibitors; C508181:IL13RA1 protein, human; D053661:Interleukin-13 Receptor alpha1 Subunit; D018123:Receptors, Interleukin; D053660:Receptors, Interleukin-13; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases