RNA聚合酶识别启动子

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1、Chapter5TranscriptionA.Transcriptioninprokaryotes5.1Basicprinciplesoftranscription5.2EscherichiacoliRNApolymerase5.3TheE.colis70promoter5.4transcriptionprocess.Anoverview,theprocessofRNAsynthesis(initiation,elongation,termination)Properties,asubunit,bsubunit,b’subunit,sig

2、ma(s)factorPromoter,s70size,-10sequence,-35sequence,transcriptionstartsite,promoterefficiencyPromoterbinding,unwinding,RNAchaininitiation,elongation,termination(rfactor)5.1:BasicprinciplesoftranscriptionTranscription:anoverview(comparisonwithreplication)TheprocessofRNAsyn

3、thesis:initiation,elongation,termination5.1-1:Transcription:anoverviewKeytermsdefinedinthissection(GeneVII)CodingstrandofDNAhasthesamesequenceasmRNA.Downstreamidentifiessequencesproceedingfurtherinthedirectionofexpression;forexample,thecodingregionisdownstreamoftheinitiat

4、ioncodon.GeneXPrimarytranscriptm7GpppAAAAAn+1upstreamdownstreammRNAUpstreamidentifiessequencesproceedingintheoppositedirectionfromexpression;forexample,thebacterialpromoterisupstreamfromthetranscriptionunit,theinitiationcodonisupstreamofthecodingregion.Transcriptionunitis

5、thedistancebetweensitesofinitiationandterminationbyRNApolymerase;mayincludemorethanonegene.PromoterisaregionofDNAinvolvedinbindingofRNApolymerasetoinitiatetranscriptionRNATerminatorisasequenceofDNA,representedattheendofthetranscript,thatcausesRNApolymerasetoterminatetrans

6、cription.RNApolymerasesareenzymesthatsynthesizeRNAusingaDNAtemplate(formallydescribedasDNA-dependentRNApolymerases).PrimarytranscriptistheoriginalunmodifiedRNAproductcorrespondingtoatranscriptionunit.Replication:synthesisoftwoDNAmoleculesusingbothparentalDNAstrandsastempl

7、ates.DuplicationofaDNAmolecule.1DNAmolecule2DNAmoleculesTranscription:synthesisofoneRNAmoleculeusingoneofthetwoDNAstrandsasatemplate.1DNAmolecule1RNAmoleculeReplication-synthesisoftheleadingstrandthesamedirectionasthereplicationforkmovesReplication-SynthesisoftheOkazaki

8、fragmentsOppositetothereplicationforkmovementCouplingthesynthesisofleadingandlaggingstrandswitha