英汉对照分子生物学导论.ppt

1、,Chapter 4 Transcription in Eukaryotes: Mechanism and Regulation,4.1 Eukaryotic RNA polymerases 4.2 Eukaryotic Promoters 4.3 General Transcription Factors and Initiation 4.4 Specific Transcription Factors and Transcriptional Regulation 4.5 Structures of specific transcription factors 4.6 Experiments

2、,4.1 真核生物RNA聚合酶 4.2 真核生物启动子 4.3 通用转录因子与 转录起始 4.4 特异转录因子与 转录调控 4.5 特异转录因子的结构 4.6 实验研究,Transcription in Eukaryotes: Mechanism and Regulation真核生物转录：机理与调控,Prokaryote,Eukaryote,Transcription in prokaryotes,Transcription in eukaryotes,Eukaryotic RNA polymerase II and transcription factors,4.1 Eukaryotic R

3、NA polymerases真核生物RNA聚合酶,Locations of RNA polymerases,Nucleolus ( RNA polymerase I ),Nucleoplasm ( RNA polymerase II and III ),RNA polymerase I,RNA polymerase I,rRNA precursor,Processing,5.8S rRNA,18S rRNA,28S rRNA,RNA polymerase III,RNA polymerase III,RNA precursor,Processing,5S rRNA,4.5S tRNA,U6 s

4、nRNA,RNA polymerase II,RNA polymerase II,RNA precursor,Processing,snRNAs,Translation,Protein,mRNA,RNA polymerase II,Holoenzyme: Core enzyme (, & ) + Subunit RNA pol II: Core subunits (1, 2 & 3) + Subunits 4-12,RNA polymerase II,4.2 Eukaryotic Promoters真核生物启动子,Prokaryotic promoter,Eukaryotic promoter

5、,Eukaryotic Promoters真核生物启动子,“I would like to have TATA box and Initiator as my promoter. What would you like?”,“Well, I prefer BRE and DPE.”,TATA box,TATAAA,-10 box TATAAT,Specialized genes have TATA boxes,TATA box,Specialized genes + Housekeeping genes Genes of development ,DPE: Downstream Promote

6、r Element,G CG,A T,Initiator / 起始子,PyPyAN PyPy,T A,BRE: TFIIB Recognition Element,CGCC,GGG CCA,4.3 General Transcription Factors and Initiation（通用转录因子与转录起始）,Prokaryotic RNA polymerase,pre-initiation complex,Eukaryotic RNA polymerase II: “I need help from other proteins.”,4.3.1 TFIID,TBP: TATA-Bindin

7、g Protein,Show 3D structure of TBP,File: TBP-TATA box complex 1.val,TAFIIs: TBP-Associated Factors II,TAFIIs: 1) Binding to DPE or Inr,TAFIIs: 2) Binding to Activator,4.3.2 Other TFIIs,Now showingInitiation of Transcription,File: biophoto7 Life Initiation of transcription (5),4.3.3 General Transcrip

8、tion factors for RNA Polymerase I and IIIRNA聚合酶 I 和III的通用转录因子,1. General TFs of RNA polymerase I,2. General TFs of RNA polymerase III,General TFs of RNA polymerase III,4.4 Specific Transcription Factors and Transcriptional Regulation特异转录因子与转录调控,Specific transcription factor,Specific Transcription Fa

9、ctors and Transcriptional Regulation特异转录因子与转录调控,4.4.1 Activators / 激活蛋白 4.4.2 Repressors / 阻遏蛋白,4.4.1 Activators / 激活蛋白,Specific transcription factors that enhance the rate of transcription are called activators.,能提高转录速率的特异转录因子称为激活蛋白。,Help recruit the pre-initiation complex. Help organize the subuni

10、ts of the pre-initiation complex, and maintain cohesion of the complex. Attract enzymes to loosen DNA from proteins, freeing important regions like the promoter.,1. Help recruit the pre-initiation complex,2. Help organize the subunits of the pre-initiation complex,3. Attract enzymes to loosen DNA,4.

11、4.2 Repressors / 阻遏蛋白,Specific transcription factors that prevent the transcription of a gene are called repressors.,能阻碍基因转录的特异转录因子称为阻遏蛋白。,Blocking the activity of activators. Blocking access of the pre-initiation complex to the promoter. Recruiting enzymes that tighten DNA around proteins.,1. Block

12、ing the activity of activators,2. Blocking access of the pre-initiation complex to the promoter.,3. Recruiting enzymes that tighten DNA around proteins,4.4.3 Enhancers and Silencers增强子和沉默子,Specific transcription factors rely on DNA sequences to tell them how each gene should be regulated. These sequ

13、ences are called enhancers or silencers, depending whether they bind activators or repressors, respectively.,特异转录因子依靠DNA序列来告诉它们应该怎样调控每一种基因。这些序列称为增强子或沉默子，分别依赖于它们结合的是激活蛋白还是阻遏蛋白。,Enhancers and Silencers,Transcription is activated,Enhancer,Transcription is repressed,Silencer,Repressor,Activator,DNA loop

14、ing / DNA成环,Sea Urchin Endo 16 gene,A red sea urchin 红海胆,4.5 Structures of Specific Transcription Factors4.5 特异转录因子的结构,?,?,Prokaryotic,Eukaryotic,Major Groove vs. Minor Groove,Major groove A T G C,Minor groove A T G C,4.5.1 DNA-Binding Motifs in Prokaryotes原核生物DNA结合基序,Recognition helix,The helix-tur

15、n-helix (HTH) motif,Negative Regulation the lac Repressor负调控lac阻遏蛋白,Show 3D structure of the lac repressor,File: lac repressor with DNA.val,The trp repressor,The trp repressor,Trp,Trp repressor,DNA,E. coli,Show 3D structure of the trp repressor,File: trp repressor.val,4.5.2 DNA-Binding Motifs in euk

16、aryote真核生物DNA结合基序,1. The homeodomain 同源异型域 2. Zinc finger motif 锌指基序 3. Leucine zipper 亮氨酸拉链 HLH motif 螺旋-环-螺旋基序,?,Eukaryotic,1. The homeodomain / 同源异型域,Mutation of homeotic genes,Homeotic genes,Show 3D structure of homeodomain,File: Homeodomain.val,Baird-Titus JM, et al.The solution structure of th

17、e native K50 Bicoid homeodomain bound to the consensus TAATCC DNA-binding siteJ. Mol. Biol. v356, p.1137-1151,2. Zinc finger motif / 锌指基序,Show 3D structure of zinc fingers,File: Zinc finger.val,3. Leucine zipper / 亮氨酸拉链,Leucines,Heterodimerization / 异源二聚化作用,Show 3D structure of leucine zipper,Wu SW,

18、 et al. Design and characterization of a multimeric DNA binding protein using Sac7d and GCN4 as templatesProteins v60, p.617-628,File: Leucine zipper.val,Yeast cells www.zeiss.de/C12567BE0045ACF1/ContentsWWWInte,4. Helix-loop-helix motif / 螺旋-环-螺旋基序,The helix-loop-helix (HLH) motif,HLH versus HTH,Th

19、e helix-loop-helix (HLH) motif,The helix-turn-helix (HTH) motif,Show 3D structure of HLH,Ferre-DAmare AR, et al.Recognition by Max of its cognate DNA through a dimeric b/HLH/Z domainNature v363, p.38-45,File: HLH.val,4.6 Experiments / 实验研究,5.5.1 RNA polymerase targets RNA聚合酶的目标 5.5.2 Modularity of Specific Transcription Factors 特异转录因子的模块化,4.6.1 RNA polymerase targetsRNA聚合酶的目标,- amanitin / 鹅膏蕈碱,Why is - amanitin poisonous?,Functions of RNA polymerases,RNA polymerase I RNA polym