Negative regulation Positive regulation 调控方式 (bound repressor inhibits transcription) (bound activator facilitates transcription) 负性调节 (a) (c) 正性调节 Operator RNA polymerase Molecular signal DNA ()causes dissociation of regulatory protein from DNA Promoter 6'+3 mRNA 1、诱导表达 3、阻遏表达 mRNA (b) (d) Molecular signal (●)causes binding of regulatory protein to DNA +3 mRNA 2、阻遏表达 4、诱导表达 mRNA Common patterns of regulation oftranscription 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 调控方式
Gene DNA Transeription Primary transcript Nucleotides Posttranscriptional processing mRNA degradation Mature mRNA Translation 基因表达 Protein Amino acids (inactive) Posttranslational processing Protein degradation Modified protein (active) ®
基因表达
调控元件 -35 region 10 region RNA start site 原核生物 DNA 5' HNA start site 高等生物 Higher CCAAT TATA eukaryotes box 03 box n RNA start site Upatrea国 酵母 Yeast activator TATA box (UAS A∩n 启动子的 RNA start site 常见组件 mRNA 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 o32,which replaces o70
高等生物 酵母 调控元件 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
调控元件 阻遏蛋白结合位点 激活蛋白结合位点 Repressor Activator binding site binding site 启动子 (operator) DNA B Genes transcribed as a unit Regulatory sequences 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 调控元件