Negative regulation Positive regulation 调控方 (bound repressor inhibits transcription) (bound activat tates transcription) 负性调节 正性调节 peru RNA polymerase olecular signal DNA ◆) causes dissociation of regulatory protein from dNA Promoter 5 3 RNA 1、诱导表达 3、阻遏表达 5~→3 mRNA olecular signal (◆ causes binding of regulatory protein to DNA 5~→3 mRNA 2、阻遏表达 ◆4诱导表达 冷2 5° mRNA Common patterns ofregulation of transcription initiation
Common patterns of regulation of transcription initiation 负性调节 正性调节 1、诱导表达 2、阻遏表达 3、阻遏表达 4、诱导表达
Gene DNA Primary transcript wwM Nucleotides Posttranscriptional mRNA degradation Mature mRNA气 Translation 基因表一 Protein Amino acids Inactive) Posttranslational processing Protein degradation Modified rotein factive)
35 reg -I0 reg RNA start site 原核生物 DNA 5 mRNA NA sun sIte 高等生物e TATA eukaryote tes bo box bo RNA start sit 酵母 Yeast activator TATA (UASI 启动子的 RNA start site TNTCNCCCTTGAA lOcccATTTA N, 常见组件 RNA」八八 Consensus sequence for promoters that regulate the expression of genes involved in the heat-shock response in E coli. Binding of RNa polymerase to heat-shock promoters is mediated by a specialized B subunit of the enzyme called o2, which replaces o70
高等生物 酵母 启动子的 常见组件 原核生物 Consensus sequence for promoters that regulate the expression of genes involved in the heat-shock response in E. coli. Binding of RNA polymerase to heat-shock promoters is mediated by a specialized β subunit of the enzyme called σ32 , which replaces σ70
阻遏蛋白结合位点 激活蛋白结合位点 Re pressor Activator binding site binding site启动子 (operator) DNA VLAB K Genes transcribed as a un gu lences 结构基因 调控序列 An operon. Genes A, B, and C are transcribed on one polycistronic mRNA. Typical regulatory sequences include binding sites for proteins that either activate or repress transcription from the promoter 操纵子结构
An operon. Genes A, B, and C are transcribed on one polycistronic mRNA. Typical regulatory sequences include binding sites for proteins that either activate or repress transcription from the promoter 操纵子结构 激活蛋白结合位点 阻遏蛋白结合位点 启动子 调控序列 结构基因