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真核生物Ⅱ类基因的转录起始是一个极其复杂并受到严格调控的过程。有两种转录起始复合物：一种是包含 Ｔ Ｂ Ｐ， Ｔ ＦⅡ和ｐｏｌ Ⅱ的分步组装复合物；另一种是 Ｒ Ｎ Ａ 聚合酶Ⅱ全酶。两条调控途径：一是组蛋白对基因的封闭作用；二是顺式作用元件与反式作用因子的相互作用。目前有关蛋白质 Ｄ Ｎ Ａ 识别的立体化学规律、蛋白质因子 Ｔ ＦⅡ Ｄ（ Ⅱ类基因转录因子 Ｄ） 以及 Ｓｗｉ／ Ｓｎｆ 蛋白在转录起始中的作用的研究均已取得一定进展。当前对转录激活机制的一种新观点为三分体模式。
The initiation of transcription of eukaryotic class II genes is an extremely complex and tightly regulated process. There are two types of transcription initiation complexes: one is a stepwise assembly consisting of T B P, T F II and pol II and the other is R N A polymerase II holoenzyme. Two regulatory pathways: one is the histone closure of genes; the other is the interaction of cis-acting elements with trans-acting factors. At present, some progress has been made in the studies on the stereochemistry of protein D N A recognition, the role of protein factor T FⅡ D (class Ⅱ gene transcription factor D) and the function of Swi / Snf protein in transcription initiation. A new view of the current transcriptional activation mechanism is the triadic mode.