基因转录.ppt

Chapter 9第九章 9.1 Introduction 9.2 Transcription is catalyzed by RNA polymerase RNA聚合酶催化转录9.3 The transcription reaction has three stages 9.4 A stalled RNA polymerase can restart 9.5 RNA polymerase consists of multiple subunits RNA聚合酶包括多个亚基9.6 RNA Polymerase consists of the core enzyme and sigma factor 9.7 Sigma factor is released at initiation 9.8 Sigma factor controls binding to DNA σ因子控制与DNA的结合9.9 Promoter recognition depends on consensus sequences 启动子识别依赖于一致序列9.10 Promoter efficiencies can be increased or decreased by mutation 9.11 RNA polymerase binds to one face of DNA RNA聚合酶与DNA的一个面连接9.12 Supercoiling is an important feature of transcription 9.13 Substitution of sigma factors may control initiation σ因子的置换可能控制起始9.14 Sigma factors directly contact DNA 9.15 Sigma factors may be organized into cascades σ因子可能被组织成层叠状 9.16 Sporulation is controlled by sigma factors 9.17 Bacterial RNA polymerase has two modes of termination细菌RNA聚合酶有两种终止模式9.18 There are two types of terminator in E. coli. 9.19 How does rho factor work? ρ因子如何作用？ 9.20 Antitermination is a regulatory event 反终止依赖于特异位点9.21 Antitermination requires sites that are independent of the terminators9.22 More subunits for RNA polymerase RNA聚合酶的更多亚基 Coding strand of DNA has the same sequence as mRNA.编码链是指此RNA 与DNA 双链中的一条链具有完全相同的序列，这条DNA 链称为编码链Downstream identifies sequences proceeding farther in the direction of expression; for example, the coding region is downstream of the initiation codonUpstream)，Dowmstream (下游)：沿着表达方向的序列。例如，编码区是在起始区的下游。.Primary transcript is the original unmodified RNA product corresponding to a transcription unit.转录的直接产物被称为初始转录本(primary transcript)。. Promoter is a region of DNA involved in binding of RNA polymerase to initiate transcription.启动子 (Promoter)：结合RNA 聚合酶并起始转录的DNA 区域 RNA polymerases are enzymes that synthesize RNA using a DNA template (formally described as DNA-dependent RNA polymerases). RNA聚合酶 (RNA polymerase )：使用DNA作为模板合成RNA的酶(正式应为DNA-依赖性RN