高级动物生物化学Chapter ppt课件.ppt

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1、Chapter7RegulationofEukaryoticGeneExpression7.1MultilevelEukaryoticGeneRegulation1.Thetypesofregulationineukaryotes2.Genestructureofeukaryotes3.FeaturesofEukaryoticGenomes4.Multi-levelofgeneexpressionandregulation7.2GeneRegulationatDNALevelChromatinRemodeling1.C

2、hangesofDNATopostructureFormationofssDNADNaseIhypersensitivesiteDNAMethylation2.DNAMethylationCpGislands-----aregenomicregionsthatcontainahighfrequencyofCGdinucleotides.-----CpGislandsparticularlyoccuratornearthetranscriptionstartsiteofhousekeepinggenes.Activetr

3、anscriptionUnmethylatedCpGislandTFRNApolRepressedtranscriptionMethylatedCpGislandTFRNApolCH3CH3CH3Housekeepinggene-Ageneinvolvedinbasicfunctionsisrequiredforthesustenanceofthecell.HousekeepinggenesareconstitutivelyexpressedLuxurygene-arethosecodingforspecialized

4、functionssynthesized(usually)inlargeamountsinparticularcelltypes.3.HistonemodificationmethylationacetylationTFHighMobilityGroup(HMG)Protein4.Changesofnucleosomenon-histonechromatinproteinshighmobilityinPAGEsolublein2-5%TCAsmall<30kDahighcontentofchargedaminoacid

5、s:Asp,Glu5.OthergeneregulationatDNALevel(1)GeneDeletion(2)GeneDuplication(3)DNARearrangement(4)GeneAmplification(5)ChemicalActivator(6)EnvironmentalActivator7.3TranscriptionalRegulation1.Cis-actingelement(1)Whatiscis-actingelement?ConceptCis-actingelements-DNAseq

6、uencesclosetoagenethatarerequiredforgeneexpression(1)PromoterCorepromoterineukaryote:TATA-box,Initiator(Inr)inprokaryote:-10region,InrFeaturesofcis-actingelementsProximalelementsofpromoterinprokaryote:-35regionineukaryote:CAAT-box,GC-boxUPE:upstreampromoter

7、elementUAS:upstreamactivatingsequence(2)TerminatorADNAsequencejustdownstreamofthecodingsegmentofagene,whichisrecognizedbyRNApolymeraseasasignaltostoptranscription.(3)EnhancerAregulatoryDNAsequencethatgreatlyenhancesthetranscriptionofagene.(4)SilencerADNAsequenceth

8、athelpstoreduceorshutofftheexpressionofanearbygene.Animation(5)InsulatorsNotranscription2.Whatistrans-actingfactor?Concepttrans-actingfactors-usuallyth