Ding Xiaofeng, Fan Changzheng, Zhou Jianlin, Zhong Yingli, Liu Rushi, Ren Kaiqun, Hu Xiang, Luo Chang, Xiao Shunyong, Wang Yeqi, Feng Du, Zhang Jian
Key Laboratory of Protein Chemistry and Developmental Biology of State Education Ministry of China, College of Life Science, Hunan Normal University, Changsha, Hunan 410081, China.
Nucleic Acids Res. 2006 May 12;34(9):2570-8. doi: 10.1093/nar/gkl319. Print 2006.
Transcription factor AP-2 regulates transcription of a number of genes involving mammalian development, differentiation and carcinogenesis. Recent studies have shown that interaction partners can modulate the transcriptional activity of AP-2 over the downstream targets. In this study, we reported the identification of GAS41 as an interaction partner of AP-2beta. We documented the interaction both in vivo by co-immunoprecipitation as well as in vitro through glutathione S-transferase (GST) pull-down assays. We also showed that the two proteins are co-localized in the nuclei of mammalian cells. We further mapped the interaction domains between the two proteins to the C-termini of both AP-2beta and GAS41, respectively. Furthermore, we have identified three critical residues of GAS41 that are important for the interaction between the two proteins. In addition, by transient co-expression experiments using reporter containing three AP-2 consensus binding sites in the promoter region, we found that GAS41 stimulates the transcriptional activity of AP-2beta over the reporter. Finally, electrophoretic mobility shift assay (EMSA) suggested that GAS41 enhances the DNA-binding activity of AP-2beta. Our data provide evidence for a novel cellular function of GAS41 as a transcriptional co-activator for AP-2beta.
转录因子AP-2调控许多涉及哺乳动物发育、分化和致癌作用的基因的转录。最近的研究表明，相互作用伙伴可以调节AP-2对下游靶标的转录活性。在本研究中，我们报告了鉴定出GAS41作为AP-2β的相互作用伙伴。我们通过免疫共沉淀在体内以及通过谷胱甘肽S-转移酶（GST）下拉试验在体外记录了这种相互作用。我们还表明这两种蛋白质在哺乳动物细胞核中共定位。我们进一步将这两种蛋白质之间的相互作用结构域分别定位到AP-2β和GAS41的C末端。此外，我们鉴定出GAS41的三个关键残基，它们对于这两种蛋白质之间的相互作用很重要。另外，通过使用在启动子区域含有三个AP-2共有结合位点的报告基因进行瞬时共表达实验，我们发现GAS41刺激AP-2β对报告基因的转录活性。最后，电泳迁移率变动分析（EMSA）表明GAS41增强了AP-2β的DNA结合活性。我们的数据为GAS41作为AP-2β的转录共激活因子的新细胞功能提供了证据。
