Abstract
Radiation-induced mouse thymic lymphomas (TL) show over-expression of IL-9R and dysregulation of downstream Jak-Stat signal transduction pathway. However, the mechanism of transcriptional dysregulation of Il9r gene was little known. In this study, we established Il9r-high expressing TL cell line, SKY8699, to examine the promoter activity region and key transcription factor of Il9r. First, the transcription starting site was compared among normal thymus, primary TL and SKY8699 by 5' RACE method. We found new transcription starting sites, which was located between 50bp to 330bp upstream of exon1. The starting site was different between normal thymocytes and TL cells. Next we focused on 2000bp upstream of exon1 in Il9r to search for the promoter by luciferase reporter assay. Seven kinds of promoter DNAs with different length were amplified from normal thymocytes by PCR, and inserted to pGL4.10[luc2] vector in order to make Il9r promoter-luciferase vectors. After transfecting the vector into SKY8699 cell, promoter activity was measured by Dual-Glo Luciferase Assay System. Preliminary data suggest that the promoter was located in this region. Further analysis of this region and key transcription factor that is binding to this Il9r transcription region are being investigated.
