Nakabeppu Y, Ryder K, Nathans D
Howard Hughes Medical Institute Laboratory, Baltimore, Maryland.
Cell. 1988 Dec 2;55(5):907-15. doi: 10.1016/0092-8674(88)90146-8.
Three members of the Jun/AP-1 family have been identified in mouse cDNA libraries: c-Jun, Jun-B, and Jun-D. We have compared the DNA binding properties of the Jun proteins by using in vitro translation products in gel retardation assays. Each protein was able to bind to the consensus AP-1 site (TGACTCA) and, with lower affinity, to related sequences, including the cyclic AMP response element TGACGTCA. The relative binding to the oligonucleotides tested was similar for the different proteins. The Jun proteins formed homodimers and heterodimers with other members of the family, and they were bound to the AP-1 site as dimers. When Fos translation product was present, DNA binding by Jun increased markedly, and the DNA complex contained Fos. The C-terminal homology region of Jun was sufficient for DNA binding, dimer formation, and interaction with Fos. Our general conclusion is that c-Jun, Jun-B, and Jun-D are similar in their DNA binding properties and in their interaction with Fos. If there are functional differences between them, they are likely to involve other activities of the Jun proteins.
在小鼠cDNA文库中已鉴定出Jun/AP-1家族的三个成员：c-Jun、Jun-B和Jun-D。我们通过在凝胶阻滞试验中使用体外翻译产物，比较了Jun蛋白的DNA结合特性。每种蛋白都能够与共有AP-1位点（TGACTCA）结合，并以较低亲和力与相关序列结合，包括环磷酸腺苷反应元件TGACGTCA。不同蛋白与所测试寡核苷酸的相对结合情况相似。Jun蛋白与家族中的其他成员形成同二聚体和异二聚体，并且它们以二聚体形式结合到AP-1位点。当存在Fos翻译产物时，Jun的DNA结合显著增加，并且DNA复合物中含有Fos。Jun的C末端同源区域足以进行DNA结合、二聚体形成以及与Fos相互作用。我们的总体结论是，c-Jun、Jun-B和Jun-D在DNA结合特性以及与Fos的相互作用方面相似。如果它们之间存在功能差异，很可能涉及Jun蛋白的其他活性。
