Workman J L, Taylor I C, Kingston R E
Department of Molecular Biology, Massachusetts General Hospital, Boston 02114.
Cell. 1991 Feb 8;64(3):533-44. doi: 10.1016/0092-8674(91)90237-s.
GAL4 derivatives containing an activation domain alleviated repression of a promoter during nucleosome assembly. A GAL4 derivative lacking an activation domain stably bound the promoter during nucleosome assembly but was not sufficient to preserve promoter function. The activation domain of GAL4 derivatives was essential for preserving promoter function, and thus the transcriptional stimulatory activity attributable to these activation domains increased dramatically during nucleosome assembly. Furthermore, promoter-bound activation domains allowed the formation of preinitiation complexes after nucleosome assembly. Finally, GAL4 derivatives containing activation domains significantly stimulated transcription through bacterially produced yeast TFIID only from nucleosome-assembled templates. These data indicate that acidic activation domains stimulate transcription by enhancing the ability of basal transcription factors to compete with nucleosomes for occupancy of the promoter.
含有激活结构域的GAL4衍生物在核小体组装过程中减轻了对启动子的抑制作用。一个缺乏激活结构域的GAL4衍生物在核小体组装过程中稳定地结合启动子，但不足以维持启动子功能。GAL4衍生物的激活结构域对于维持启动子功能至关重要，因此这些激活结构域的转录刺激活性在核小体组装过程中显著增加。此外，结合在启动子上的激活结构域允许在核小体组装后形成预起始复合物。最后，含有激活结构域的GAL4衍生物仅通过细菌产生的酵母TFIID从核小体组装的模板中显著刺激转录。这些数据表明，酸性激活结构域通过增强基础转录因子与核小体竞争启动子占据的能力来刺激转录。
