Transcriptional regulation of the mouse interleukin-2 receptor b chain gene by Ets and Egr-1 Sang-Kyu Ye a , Tack Joong Kim b,1 , Sung Sik Won b , Taek Joon Yoon b , Tae Kyu Park b , Yung Choon Yoo c , Yong-Nyun Kim d , Hai Chon Lee e , Koichi Ikuta e , Myung-Hee Chung a , Kwang Ho Lee b, * a Department of Pharmacology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-799, Republic of Korea b Bio-Food and Drug Research Center, Department of Biotechnology, Faculty of Life Science, College of Natural Science Konkuk University, Chungju 380-701, Republic of Korea c Department of Microbiology, College of Medicine, Konyang University, Nae-Dong 26 Nonsan, Chungnam 320-711, Republic of Korea d Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea e Department of Biological Responses Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan Received 6 February 2005 Abstract To clarify the mechanisms and factors involved in the regulation of mouse IL-2Rb gene expression, we isolated the 5 0 -flanking region of IL-2Rb gene and investigated the promoter activity. Here we elucidated the positive regulatory regions, the most potent of which are located between À50 to À30 bp and À164 to À135 bp. These regions contain a potentially functional Ets and Egr-1-bind- ing sites whose mutations abrogate promoter activity. Data from electrophoretic mobility shift assay indicate that Ets and Egr-1, but not Sp1, bind to the positive regulatory regions, À50 to À30 bp and À164 to À135 bp, respectively. Furthermore, recruitment of Ets and Egr-1 at endogenous IL-2Rb promoter segments in an IL-2-dependent F7 cells was verified by the chromatin immunoprecip- itation assay. This study for the first time delineates the molecular mechanisms underlying regulation of mouse IL-2Rb gene tran- scription by Ets family proteins, partially with Egr-1, and thereby further elucidates the molecular basis of lymphocyte activation and differentiation. Ó 2005 Elsevier Inc. All rights reserved. Keywords: Mouse IL-2Rb gene promoter; Ets; Egr-1; ChIP Interleukin-2 (IL-2) exerts its biological activities through binding to specific receptor on target cells. IL-2 binding to the high-affinity IL-2 receptor (IL-2R) stimu- lates the events indispensable for cellular proliferation and differentiation of lymphocyte population. The func- tional IL-2R is a multi-chain complex composed of three distinct subunits, the IL-2Ra, b, and c chain. The IL-2Rb chain not only contributes to ligand-binding affinity but also plays pivotal role in mediating IL-2-induced signal transduction [1–3]. IL-2Ra gene expression has been studied in great de- tail, but relatively little is known about the molecular mechanisms by which the IL-2Rb chain gene is regulated. Several studies have shown that IL-2Rb gene expression is induced after stimulation by anti-CD3, anti-CD28, CD-2 plus anti-CD28 antibody; IL-4 and IL-5 [4,5]. In contrast, the expression of IL-2Ra and IL-2Rb was downregulated by IL-3 and IL-4, 0006-291X/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.bbrc.2005.02.073 * Corresponding author. Fax: +82 43 851 5235. E-mail address: kwangho@kku.ac.kr (K.H. Lee). 1 Present address: Department of Biomembrane and Biofunctional Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12 Nishi 6, Kita-ku, Sapporo 060-0812, Japan. www.elsevier.com/locate/ybbrc Biochemical and Biophysical Research Communications 329 (2005) 1094–1101 BBRC