Boeger Hinrich, Bushnell David A, Davis Ralph, Griesenbeck Joachim, Lorch Yahli, Strattan J Seth, Westover Kenneth D, Kornberg Roger D
Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
FEBS Lett. 2005 Feb 7;579(4):899-903. doi: 10.1016/j.febslet.2004.11.027.
An RNA polymerase II promoter has been isolated in transcriptionally activated and repressed states. Topological and nuclease digestion analyses have revealed a dynamic equilibrium between nucleosome removal and reassembly upon transcriptional activation, and have further shown that nucleosomes are removed by eviction of histone octamers rather than by sliding. The promoter, once exposed, assembles with RNA polymerase II, general transcription factors, and Mediator in a approximately 3 MDa transcription initiation complex. X-ray crystallography has revealed the structure of RNA polymerase II, in the act of transcription, at atomic resolution. Extension of this analysis has shown how nucleotides undergo selection, polymerization, and eventual release from the transcribing complex. X-ray and electron crystallography have led to a picture of the entire transcription initiation complex, elucidating the mechanisms of promoter recognition, DNA unwinding, abortive initiation, and promoter escape.
一个RNA聚合酶II启动子已在转录激活和抑制状态下被分离出来。拓扑学和核酸酶消化分析揭示了转录激活时核小体去除与重新组装之间的动态平衡，并进一步表明核小体是通过组蛋白八聚体的驱逐而非滑动来去除的。启动子一旦暴露，就会与RNA聚合酶II、通用转录因子和中介体组装成一个约3兆道尔顿的转录起始复合物。X射线晶体学已在原子分辨率下揭示了转录过程中RNA聚合酶II的结构。这种分析的扩展展示了核苷酸如何进行选择、聚合以及最终从转录复合物中释放。X射线和电子晶体学已得出整个转录起始复合物的图像，阐明了启动子识别、DNA解旋、流产起始和启动子逃逸的机制。
