CHAPTER 16 Gene Regulation in Prokaryotes Topic 1: Principles of Transcription Regulation 5/10/2005 劣溪字 Wuhan University
12 Topic 1: Principles of Transcription Regulation CHAPTER 16 Gene Regulation in Prokaryotes 5/10/2005
2. 1. Gene Expression is Controlled by 3. Regulatory Proteins(调控蛋白) Gene expression is very often controlled by Extracellular Signals, which are communicated to genes by regulatory proteins: Positive requlators or activators INCREASE the transcription F>Negative regulators or repressors DECREaSE or elIMinate the transcription 13
13 1. Gene Expression is Controlled by Regulatory Proteins (调控蛋白) Gene expression is very often controlled by Extracellular Signals, which are communicated to genes by regulatory proteins: ➢ Positive regulators or activators INCREASE the transcription ➢ Negative regulators or repressors DECREASE or ELIMINATE the transcription Principles of Transcription Regulation
2. 2. Gene expression is controlled at 世 different stages(基因表达可以发生在不同 时期) E >The bulk of gene regulation takes place at the initiation of transcription Some involve transcriptional elongation/termination, RNA processing, and translation of 营 the mRNA into protein 14
14 2. Gene expression is controlled at different stages (基因表达可以发生在不同 时期) Principles of Transcription Regulation ➢The bulk of gene regulation takes place at the initiation of transcription. ➢Some involve transcriptional elongation/termination, RNA processing, and translation of the mRNA into protein
RNA polymerase Fig 12-3-initiation upstream downstream DNA DNA promoter Promoter Binding bindu (closed complex) (closed complex promoter melting Promoter“ melting (open complex) (open complex) Promoter initial transcription escape/Initial RNA transcription
15 Fig 12-3-initiation Promoter Binding (closed complex) Promoter “melting” (open complex) Promoter escape/Initial transcription
Fig 12-3-Elongation and termination Elongation s Termination RNA polymerase terminates and releases RNA 16
16 Fig 12-3-Elongation and termination Termination Elongation