高级动物生物化学课件.ppt

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1、RegulationofGeneExpressioninEukaryotesBIT220Chapter24OpportunitiesforthecontrolofgeneexpressionintheeukaryoticcellGeneExpressionSpatial–noteverygeneproductneededineverycelltypeTemporal–DifferentgenesexpressedatdifferenttimesEnvironmentalstimuliHormonesE

2、speciallyseenindevelopment-formationoftissuesandorgansSpatialandTemporalexamplesSpatialTubulininplantsMicrotubulesfoundinmanyplacesTUA1-pollengrains;TUB1-rootsTemporalFigure24.2,globingenesTetramer(thenaddhemegroup)Someinembryo,fetusandafterbirthPseudog

3、enes–duplicatedgenew/terminationsignalRegulationChap12–RNAprocessing5’capPolyAtailIntronremovalIneukaryotes,morelevelofregulationthanprokaryotesduetocomplexorganellesAlternatesplicingFigures24.4and24.5TroponinTgeneSexlethalgenesinDrosophila–helpsdefines

4、exualdifferentiationinfliesCytoplasmiccontrolmRNAstability:Longvs.shortlivedmRNAsLong-manyroundsproteinsynthesisfromonemRNAShort–rapidlydegraded,needsmoretranscriptiontoreplenish(half-life)RapidmRNAdegradationmaybedesirableHalf-lifeproblemwithmakingadru

5、g,toomRNAstabilityPolyAtails–canaddstabilityLongertailsstabilizemessagemoreE.g.,histonemRNAsnopolyAtails;messageveryshortlivedInductionoftranscriptionNotfoundasoftenineukaryotesasinprokaryotesInductioncanworkby:TemperatureLighthormonesInductionoftranscr

6、iptionTemperatureSynthesizeheatshockproteins(HSPs)Transcriptionalregulation–stressofhighheatsignalsHSPstobetranscribedStudiedinDrosophila-butoccursinhumansalsoInductionoftranscriptionLightFigure24.7RBC(ribulose1,5bisphosphatecarboxylase)Plantsmustabsorb

7、lightenergyRBCproducedwhenplantsareexposedtolight(seeNorthernblotinfigure)-rememberwhatisaNorthernblot?)InductionoftranscriptionHormonesSecreted,circulatethroughbody,makecontactwithtargetcellandregulatetranscriptionCalledsignalmolecules2classesofhormone

8、sthatactivatetranscriptionSteroidhormonesPeptidehormonesSteroidhormonesSmall,lipidmoleculesderivedfromcholesterolEasilypassthroughcellmembranesExamplesEstrogenProgesteroneTestosteroneGlucocorticoidsSteroidhormonesFigure24.8HRE’s-