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1、基因啟動子genepromoters現(xiàn)代遺傳學(xué)精要Newwords1、promoter[pr?u'm?ut?]啟動子2、geneticexpression[d??'net?k][?k'spre?(?)n;ek-]基因表達(dá)3、element['el?m(?)nt]n.元素；要素；元件4、enhanser5、inducible[in'dju:s?bl]adj.可誘導(dǎo)的；可導(dǎo)致的6、lactoseoperon['l?kt?us]['?p?r?n]乳糖操縱子主要介紹內(nèi)容：一、啟動子結(jié)構(gòu)的發(fā)現(xiàn)二、啟動子的元件(promoterelement)三、啟動子的類型(promotertype)四、啟動子的
2、特點（Promotercharacteristics）五、啟動子的序列分析(Promotersequenceanalysis)啟動子1、啟動子：位于結(jié)構(gòu)基因5’端上游、能夠指導(dǎo)RNA聚合酶同模板正確結(jié)合、啟動基因轉(zhuǎn)錄的一段DNA序列。Promoter:locatedinthestructuralgene5'upstream,canguidetheRNApolymerasewithtemplatecorrectly,startaDNAsequenceofthegenetranscription一、啟動子的發(fā)現(xiàn)過程Pribnowdesignedanexperiment,heputtheRNA
3、polymeraseholoenzymewithprokaryotestemplateDNAbinding,DNAhydrolysiswithDNase,andthenextractedwithphenol,theprecipitatepurifiedDNAobtainedafteraprotectedRNApolymeraseDNAfragment,about41~44nucleotidepairs.HehasseparatedfdphageT7bacteriophageA2andA3promoterPRpromoterofmacrophagesσbacteriaandE.colila
4、ctoseoperonUV5promoterparagraph5enzymeprotectedarea,andsequenceanalysislaterwasdoneover50promotersequenceanalysisrevealedthat,intheprotectedareashaveacommonsequenceoffivenucleotides,RNApolymerasecloselyintegrated,nowknownasthePribnowDistrict(Pribnowbox),thecenteroftheareaisapproximatelylocatedthe
5、startingpointattheupstream10bp,itisalsoreferredtoasthe-10region.Laterfoundat-35bpthetheanothercommonsequences(TTGACA)Ineukaryoticgenes,Hogness,etc.globingenefirstdiscoveredsimilarPribrowzoneHognesszone(Hognessbox),whichislocatedupstreamofthetranscriptioninitiationpointat-25~-30bpthecommonsequence
6、likeTAAA,alsoknownasastheTATADistrict.At-70~-78bpupstreamofthestartsiteSterileanothersectionofthecommonsequenceoftheCCAATsequencecorrespondingwiththethe-35bpDistrictprokaryotes.CalledtheCAATarea(CAATthehox).二、啟動子元件真核啟動子中包含了許多調(diào)節(jié)基（regulatorgene）轉(zhuǎn)錄的元件，它們控制著基因表達(dá)的強(qiáng)弱或者時空差異。根據(jù)對基因表達(dá)（geneticexpression）的必須
7、性，這些元件分為2類：核心啟動子元件（corepromoterelement）和上游啟動子元件(upstreampromoterelement)（1）TATA框(TATAbox)：位于5′端轉(zhuǎn)錄起始點上游約20-30個核苷酸的地方。TATA框是一個短的核苷酸序列，其堿基順序為TATAATAA。TATA框是RNA聚合酶的重要的接觸點，它能夠使酶準(zhǔn)確地識別轉(zhuǎn)錄的起始點并開始轉(zhuǎn)錄。當(dāng)TATA框中的堿基順序有所改變時，mRNA的轉(zhuǎn)錄就會從不
