Kaminuma Osamu, Elly Chris, Tanaka Yoshihiko, Mori Akio, Liu Yun-Cai, Altman Amnon, Miyatake Shoichiro
Department of Immunology, The Tokyo Metropolitan Institute of Medical Science, 2-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan.
FEBS Lett. 2002 Mar 13;514(2-3):153-8. doi: 10.1016/s0014-5793(02)02316-5.
The role of Vav in the transcriptional regulation of the human interferon-gamma (IFN-gamma) promoter was investigated. Overexpression of Vav in Jurkat-TAg cells enhanced T cell receptor (TCR)-induced activation of a luciferase (Luc) reporter gene construct driven by cis-regulatory element of the IFN-gamma gene (-346 to +7). Electrophoresis mobility shift and Luc reporter assays demonstrated that the DNA-binding and transcriptional activity of the proximal AP-1-dependent NFAT site (positions -172 to -138), the AP-1/Ying-Yang 1 (YY1)-binding site (-209 to -184), and a consensus AP-1-binding site were upregulated by Vav. Vav enhanced TCR-induced activation of c-Jun N-terminal kinase (JNK) and its upstream regulator, Rho family GTPases. Finally, coexpression of a dominant-negative Rac1 mutant suppressed Vav-mediated upregulation of the transcriptional and DNA-binding activity of the proximal NFAT/AP-1 site and the AP-1/YY1 site, as well as the complete IFN-gamma promoter activity. Vav activates the IFN-gamma promoter via upregulation of AP-1-binding through a Rac1/JNK pathway.
研究了Vav在人γ-干扰素（IFN-γ）启动子转录调控中的作用。在Jurkat-TAg细胞中过表达Vav可增强T细胞受体（TCR）诱导的由IFN-γ基因顺式调控元件（-346至+7）驱动的荧光素酶（Luc）报告基因构建体的激活。电泳迁移率变动分析和Luc报告基因检测表明，近端AP-1依赖性NFAT位点（位置-172至-138）、AP-1/阴阳1（YY1）结合位点（-209至-184）以及共有AP-1结合位点的DNA结合和转录活性均被Vav上调。Vav增强了TCR诱导的c-Jun氨基末端激酶（JNK）及其上游调节因子Rho家族GTP酶的激活。最后，共表达显性负性Rac1突变体可抑制Vav介导的近端NFAT/AP-1位点和AP-1/YY1位点的转录和DNA结合活性上调，以及完整的IFN-γ启动子活性。Vav通过Rac1/JNK途径上调AP-1结合来激活IFN-γ启动子。
