chapt07RNA的转录合成分子生物学教程.ppt

8-* 7.6 类型II基因的转录因子和转录起始复合物 真核生物基因转录与原核生物不同，RNA聚合酶不能直接与启动子相结合，需要转录因子的参与。 转录因子（transcription factor,TF） ：真核生物RNA聚合酶起始转录所需要的各种蛋白质辅助因子成为转录因子。 8-* 转录因子分为两大类： ②基因特异性转录因子Gene specific transcription factors ①通用转录因子General (basal) transcription factors 作用于基本启动子上的辅助因子成为通用转录因子 特定类型基因启动子所必须辅助因子称为基因特异性转录因子 8-* 基本转录因子是广泛存在于各类细胞中的DNA结合蛋白，一般是指与RNA聚合酶II识别的启动子相结合，促进RNA聚合酶II转录所必需的蛋白因子。(TFIIx): required for all promoters; + RNA pol = basal transcription apparatus. 1 基本转录因子 General (basal) transcription factors 8-* TF for RNA polymerase II in eukaryote Proteins Subunit Relative M.W./103 Functions RNA pol II 12 10~220 to catalyze RNA synthesis TBP 1 38 binding TATA region on promoter TF II A 3 12,19,35 to prove TFIID bind with promoter and compete  with inhibited factors; interacts with TBP and TFII D. TF II B 1 35 to binds with TFIID-DNA and acts with TFIIE/F  being targets of transcriptional factors TF II D 12 150~250 TBP is basic TF and binds on TATA box and interacts with TAF and other regulatory factors TF II E 2 34,57 to interact with TFIIB/RNA pol II and improve TFIIH CTP kinase activity to arrest TF II H，It has a ability of ATPase and helicase TF II F 2 30,74 to interact with TFIIB/RNA pol II to inhibit RNA pol  II unspecific binding with DNA sequence TF II G similar t