细胞分子生物学第11章基因表达的转录调控.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,11.1 Overview of Eukaryotic Gene Control and RNA Polymerases,The nuclei of all eukaryotic cells contain three different RNA polymeras,designated I,II,and III.,RNA polymerase I,located in the nucleolus,transcribes genes encoding precursor rRNA(pre-rRNA).,RNA polymerase II,transcribes all protein-coding genes;,RNA polymerase III,transcribes genes encoding tRNAs.,11.2 Regulatory Sequences in Protein-Coding Genes,General pattern of control elements that regulate gene expression in multicellular eukaryotes and yeast,Enhancer:能增强转录起始的序列；promoter-proximal elements：(近端启动子元件)位于起始位点上游100-200个碱基。某些情况下，具有细胞类型特异性，只在特殊的分化细胞类型中起作用,11.3 Activators and Repressors of Transcription,Activators Are Modular Proteins Composed of Distinct Functional Domains,Repressors Are the Functional Converse of Activators,Like activators,most eukaryotic repressors are modular proteins that have two functional domains:a DNA-binding domain and a repression domain,11.6 Regulation of Transcription-Factor Activity,Hormone Binding to a Nuclear Receptor Regulates Its Activity as a Transcription Factor,All Nuclear Receptors Share a Common Domain Structure,11.7 Regulated Elongation and Termination of Transcription,11.8 Other Eukaryotic Transcription Systems,other two eukaryotic nuclear RNA polymerases,Pol I and Pol III,and by the distinct polymerases that transcribe,mitochondrial and chloroplast DNA,.,The process of,transcription initiation,by,Pol I and Pol III,is,similar to,that by,Pol II,but requires,different general transcription factors,is directed by,different promoter elements,and does,not require ATP hydrolysis.,Thanks,