《英汉对照分子生物学导论》课件Chapter 4.ppt

1、Chapter 4 Transcription in Eukaryotes:Mechanism and Regulation4.1 Eukaryotic RNA polymerases4.2 Eukaryotic Promoters4.3 General Transcription Factors and Initiation4.4 Specific Transcription Factors and Transcriptional Regulation4.5 Structures of specific transcription factors4.6 Experiments4.1 真核生物

2、真核生物RNA聚合酶聚合酶4.2 真核生物启动子真核生物启动子4.3 通用转录因子与通用转录因子与 转录起始转录起始4.4 特异转录因子与特异转录因子与 转录调控转录调控4.5 特异转录因子的结构特异转录因子的结构4.6 实验研究实验研究Transcription in Eukaryotes:Mechanism and Regulation真核生物转录：机理与调控真核生物转录：机理与调控ProkaryoteEukaryoteTranscription in prokaryotesTranscription in eukaryotesEukaryotic RNA polymerase II an

3、d transcription factorsSpecific transcription factorGeneral transcription factorsGeneral transcription factors4.1 Eukaryotic RNA polymerases真核生物真核生物RNA聚合酶聚合酶Locations of RNA polymerasesNucleolus(RNA polymerase I)Nucleoplasm(RNA polymerase II and III)RNA polymerase IRNA polymerase IrRNAprecursorProce

4、ssing5.8SrRNA18SrRNA28SrRNARNA polymerase IIIRNA polymerase IIIRNAprecursorProcessing5SrRNA4.5StRNAU6snRNARNA polymerase IIRNA polymerase IIRNAprecursorProcessingsnRNAsTranslationProteinmRNARNA polymerase IIHoloenzyme:Core enzyme(,&)+Subunit RNA pol II:Core subunits(1,2&3)+Subunits 4-12RNA polymeras

5、e II4.2 Eukaryotic Promoters真核生物启动子真核生物启动子ProkaryoticpromoterEukaryotic promoterEukaryotic Promoters真核生物启动子真核生物启动子“I would like to have TATA box and Initiator as my promoter.What would you like?”“Well,I prefer BRE and DPE.”TATA boxTATAAA-10 boxTATAATSpecialized genes have TATA boxesTATA boxSpecializ

6、ed genes +Housekeeping genes Genes of development DPE:Downstream Promoter ElementG CGATInitiator /起始子起始子PyPyAN PyPyTABRE:TFIIB Recognition ElementCGCCCGCCGGGGGGCCACCA4.3 General Transcription Factors and Initiation（通用转录因子与转录起始）（通用转录因子与转录起始）Prokaryotic RNApolymerasepre-initiation complexEukaryotic RN

7、Apolymerase II:“I need help fromother proteins.”4.3.1 TFIIDTBP:TATA-Binding ProteinShow 3D structure of TBPFile:TBP-TATA box complex 1.valTAFIIs:TBP-Associated Factors IITAFIIs:1)Binding to DPE or InrTAFIIs:2)Binding to Activator4.3.2 Other TFIIsNow showingInitiation of TranscriptionFile:biophoto7 L

8、ife Initiation of transcription(5)4.3.3 General Transcription factors for RNA Polymerase I and IIIRNA聚合酶聚合酶 I 和和III的通用转录因子的通用转录因子1.General TFs of RNA polymerase I2.General TFs of RNA polymerase IIIGeneral TFs of RNA polymerase III4.4 Specific Transcription Factors and Transcriptional Regulation特异转录因

9、子与转录调控特异转录因子与转录调控Specific transcription factorSpecific Transcription Factors and Transcriptional Regulation特异转录因子与转录调控特异转录因子与转录调控4.4.1 Activators /激活蛋白激活蛋白4.4.2 Repressors /阻遏蛋白阻遏蛋白4.4.1 Activators /激活蛋白激活蛋白Specific transcription factors that enhance the rate of transcription are called activators.能

10、提高转录速率能提高转录速率的特异转录因子的特异转录因子称为称为激活蛋白激活蛋白。1.Help recruit the pre-initiation complex.2.Help organize the subunits of the pre-initiation complex,and maintain cohesion of the complex.3.Attract enzymes to loosen DNA from proteins,freeing important regions like the promoter.1.Help recruit the pre-initiatio

11、n complex2.Help organize the subunits of the pre-initiation complex3.Attract enzymes to loosen DNA4.4.2 Repressors /阻遏蛋白阻遏蛋白Specific transcription factors that prevent the transcription of a gene are called repressors.能阻碍基因转录能阻碍基因转录的特异转录因子的特异转录因子称为称为阻遏蛋白阻遏蛋白。1.Blocking the activity of activators.2.B

12、locking access of the pre-initiation complex to the promoter.3.Recruiting enzymes that tighten DNA around proteins.1.Blocking the activity of activators2.Blocking access of the pre-initiation complex to the promoter.3.Recruiting enzymes that tighten DNA around proteins4.4.3 Enhancers and Silencers增强

13、子和沉默子增强子和沉默子Specific transcription factors rely on DNA sequences to tell them how each gene should be regulated.These sequences are called enhancers or silencers,depending whether they bind activators or repressors,respectively.特异转录因子依靠特异转录因子依靠DNA序列来告诉它序列来告诉它们应该怎样调控每们应该怎样调控每一种基因。这些序一种基因。这些序列称为列称为增强子

14、增强子或或沉沉默子默子，分别依赖于，分别依赖于它们结合的是激活它们结合的是激活蛋白还是阻遏蛋白。蛋白还是阻遏蛋白。Enhancers and SilencersTranscriptionis activatedEnhancerTranscriptionis repressedSilencerRepressorActivatorDNA looping /DNA成环成环Sea Urchin Endo 16 geneA red sea urchin红海胆红海胆4.5 Structures of Specific Transcription Factors4.5 特异转录因子的结构特异转录因子的结构?

15、ProkaryoticEukaryoticMajor Groove vs.Minor GrooveMajor grooveA TG CMinor grooveA TG C4.5.1 DNA-Binding Motifs in Prokaryotes原核生物原核生物DNA结合基序结合基序RecognitionhelixThe helix-turn-helix(HTH)motifNegative Regulation the lac Repressor负调控负调控lac阻遏蛋白阻遏蛋白Show 3D structure of the lac repressorFile:lac repressor

16、with DNA.valThe trp repressorThe trp repressorTrpTrp repressorDNAE.coliOperatorShow 3D structure of the trp repressorFile:trp repressor.val4.5.2 DNA-Binding Motifs in eukaryote真核生物真核生物DNA结合基序结合基序1.The homeodomain 同源异型域同源异型域2.Zinc finger motif 锌指基序锌指基序3.Leucine zipper 亮氨酸拉链亮氨酸拉链4.HLH motif 螺旋螺旋-环环-螺旋

17、基序螺旋基序?Eukaryotic1.The homeodomain /同源异型域同源异型域Similar to HTHof prokaryotesMutation of homeotic genesHomeotic genesShow 3D structure of homeodomainFile:Homeodomain.valBaird-Titus JM,et al.The solution structure of the native K50 Bicoid homeodomain bound to the consensus TAATCC DNA-binding site J.Mol.

18、Biol.v356,p.1137-1151 2.Zinc finger motif /锌指基序锌指基序Show 3D structure of zinc fingersFinger 1Finger 2Finger 3File:Zinc finger.val3.Leucine zipper /亮氨酸拉链亮氨酸拉链LeucinesHeterodimerization /异源二聚化作用异源二聚化作用Show 3D structure of leucine zipperWu SW,et al.Design and characterization of a multimeric DNA binding

19、 protein using Sac7d and GCN4 as templates Proteins v60,p.617-628 File:Leucine zipper.valYeast cells www.zeiss.de/C12567BE0045ACF1/ContentsWWWInte 4.Helix-loop-helix motif /螺旋螺旋-环环-螺旋基序螺旋基序The helix-loop-helix(HLH)motifHLH versus HTHThe helix-loop-helix(HLH)motifThe helix-turn-helix(HTH)motifShow 3D

20、 structure of HLHFerre-DAmare AR,et al.Recognition by Max of its cognate DNA through a dimeric b/HLH/Z domain Nature v363,p.38-45 File:HLH.val4.6 Experiments /实验研究实验研究5.5.1 RNA polymerase targets RNA聚合酶的目标聚合酶的目标5.5.2 Modularity of Specific Transcription Factors 特异转录因子的模块化特异转录因子的模块化4.6.1 RNA polymera

21、se targetsRNA聚合酶的目标聚合酶的目标-amanitin /鹅膏蕈碱鹅膏蕈碱 Why is-amanitin poisonous?Functions of RNA polymerasesRNA polymerase IRNA polymerase IIRNA polymerase IIIrRNA precursorHigh concentrationof-amanitinRNA polymerase Iproduces rRNAprecursors.Functions of RNA polymerasesRNA polymerase IRNA polymerase IIRNA po

22、lymerase IIIrRNA precursortRNA,5S rRNA Low concentrationof-amanitinRNA polymerase IIIproduces tRNA,5S rRNA and other snRNAs.4.6.2 Modularity of Specific Transcription Factors特异转录因子的模块化特异转录因子的模块化ModuleexchangeThe reporter genes /报告基因报告基因physicalsciences.ucsd.edu/outreach/image_gall.www.bio- Brain cancer models Human U-87-RFP glioma growing in brain of nude mouse.脑瘤模型：生长在裸鼠脑中的人神经胶质瘤脑瘤模型：生长在裸鼠脑中的人神经胶质瘤 RFPGFPThe modularity of Gal4The modularity of Gal4The modularity of Gal4