Vashee S, Kodadek T
Department of Chemistry and Biochemistry, University of Texas, Austin 78712, USA.
Proc Natl Acad Sci U S A. 1995 Nov 7;92(23):10683-7. doi: 10.1073/pnas.92.23.10683.
Most proteins that activate RNA polymerase II-mediated transcription in eukaryotic cells contain sequence-specific DNA-binding domains and "activation" regions. The latter bind general transcription factors and/or coactivators and are required for high-level transcription. Their function in vivo is unknown. Since several activation domains bind the TATA-binding protein (TBP), TBP-associated factors, or other general factors in vitro, one role of the activation domain may be to facilitate promoter occupancy by supporting cooperative binding of the activator and general transcription factors. Using the GAL4 system of yeast, we have tested this model in vivo. It is demonstrated that the presence of a TATA box (the TBP binding site) facilitates binding of GAL4 protein to low- and moderate-affinity sites and that the activation domain modulates these effects. These results support the cooperative binding model for activation domain function in vivo.
大多数在真核细胞中激活RNA聚合酶II介导转录的蛋白质都包含序列特异性DNA结合结构域和“激活”区域。后者结合通用转录因子和/或共激活因子，是高水平转录所必需的。它们在体内的功能尚不清楚。由于几个激活结构域在体外能结合TATA结合蛋白（TBP）、TBP相关因子或其他通用因子，激活结构域的一个作用可能是通过支持激活剂与通用转录因子的协同结合来促进启动子占据。利用酵母的GAL4系统，我们在体内测试了这个模型。结果表明，TATA框（TBP结合位点）的存在促进了GAL4蛋白与低亲和力和中等亲和力位点的结合，并且激活结构域调节了这些效应。这些结果支持了激活结构域在体内功能的协同结合模型。
