Maguire K, Shi X P, Horikoshi N, Rappaport J, Rosenberg M, Weinmann R
Wistar Institute, Philadelphia, Pennsylvania 19104.
Oncogene. 1991 Aug;6(8):1417-22.
We have studied interactions between bacterially produced E1A linked to Sepharose and the various DNA-binding proteins present in HeLa cell nuclear extracts (NE). DNA-binding activities and cross-reactive polypeptides recognizing the cAMP-responsive element (CRE) and the activator protein 1 (AP1) sites were bound to the E1A column, whereas nuclear factor 1 (NF1) and the activator protein 2 (AP2) DNA-binding activities were not retained by E1A. The binding activities that were retained belonged to the CRE and JUN protein family, as judged by Western blot analysis. Authentic CRE-BP1, c-Jun and c-Fos proteins produced by in-vitro translation also bound to the E1A column. However, efficient binding of in-vitro-translated CRE-BP1 and c-Fos proteins to E1A required preincubation with NE. We show here that immobilized E1A sequesters several cellular upstream transcription activators, and suggest a role for members of the AP1 family of transcription factors in E1A-mediated gene regulation.
我们研究了与琼脂糖珠相连的细菌产生的E1A与HeLa细胞核提取物（NE）中存在的各种DNA结合蛋白之间的相互作用。识别环磷酸腺苷反应元件（CRE）和激活蛋白1（AP1）位点的DNA结合活性及交叉反应性多肽与E1A柱结合，而核因子1（NF1）和激活蛋白2（AP2）的DNA结合活性未被E1A保留。通过蛋白质免疫印迹分析判断，保留的结合活性属于CRE和JUN蛋白家族。体外翻译产生的 authentic CRE-BP1、c-Jun和c-Fos蛋白也与E1A柱结合。然而，体外翻译的CRE-BP1和c-Fos蛋白与E1A的有效结合需要先与NE预孵育。我们在此表明，固定化的E1A隔离了几种细胞上游转录激活因子，并提示转录因子AP1家族成员在E1A介导的基因调控中发挥作用。
