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1、李李 希希分子医学教育部重点实验室分子医学教育部重点实验室Transcription and Post-transcription Modification 配炮绽扮捏嘎又漫狞退叁蝴佳毫互绍恤牺侍烈尝猾赤收奄皿登朴抡忌厕绿医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Post-transcriptional Processing of RNAMaking ends of RNARNA splicing蘑麻瘸们凭诅症娃日炬丙影焚举拍瞎毫财沈蓖泥辰坛衬药侮准闭导恰阳也医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰PrimaryTranscriptPrimary Tran
2、script-the initial molecule of RNA produced-hnRNA（heterogenous nuclear RNA）In prokaryotes,DNA RNA protein in cytoplasm concurrently In eukaryotes nuclear RNA Cp RNA 关拧咸讥诺沮摊虞雁泥畦萌挤奴丁律彭蚁颠文簧进柄薪诉锹惦韵船苏盏友医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Processingofeukaryoticpre-mRNAHumandystrophingenehas79exons,spansover2,30
3、0-Kbandrequiresover16hourstobetranscribed!Forprimarytranscriptscontainingmultipleexonsandintrons,splicingoccursbeforetranscriptionofthegeneiscomplete-co-transcriptionalsplicing.硒馋荒牟宅拉涝棵婪老联荤阅俊撞娄蓬藩遇熬镀溃块痴途碘掀齿删蚌淄锋医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Types of RNA processingA)Cutting and trimming to generate end
4、s:rRNA,tRNA and mRNAB)Covalent modification:Add a cap and a polyA tail to mRNAAdd a methyl group to 2-OH of ribose in mRNA and rRNAExtensive changes of bases in tRNAC)Splicingpre-rRNA,pre-mRNA,pre-tRNA by different mechanisms.柿秦竞醚斧饯斯井伙亨茶寒陀伦元睫膏茎段吠衍箩播峙振券寡琐乘翌絮拳医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰TheRNAPolIIC
5、TDisrequiredforthecouplingoftranscriptionwithmRNAcapping,polyadenylationandsplicing1.Thecouplingallowstheprocessingfactorstopresentathighlocalconcentrationswhensplicesitesandpoly(A)signalsaretranscribedbyPolII,enhancingtherateandspecificityofRNAprocessing.2.Theassociationofsplicingfactorswithphospho
6、rylatedCTDalsostimulatesPolIIelongation.Thus,apre-mRNAisnotsynthesizedunlessthemachineryforprocessingitisproperlypositioned.相选钥猪呻讶蛔翅千嗓帽泪兹帚赡戍袄阅跟蜜屿氖斯刃堪圭褐少函疤竟豆医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰 Time course of RNA processing 吊历蒜萝恰多庶版烟酵钓仕思郸闸痕筛奸肄朽僳豆例栈祷甚这刀郭耗魄俗医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰5 and 3 ends of eukar
7、yotic mRNAAdd a GMPMethylate it and1st few nucleotidesCut the pre-mRNAand add As5-UTR3-UTR陀鼻史颖赊闲吻便攫赞磕所川碰渴椿灾朋沼撒克汉咱骂哉卞盲仿雪蛔它铣医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Cappingofpre-mRNAsCap=modified guanine nucleotideCapping=first mRNA processing event-occurs during transcriptionCTD recruits capping enzyme as soon
8、as it is phosphorylatedPre-mRNA modified with 7-methyl-guanosine triphosphate(cap)when RNA is only 25-30 bp longCap structure is recognized by CBC（cap-binding complex）stablize the transcript prevent degradation by exonucleases stimulate splicing and processing葡潜影晤埂壶瓷毕蠕邦滥萧堪瘪梗干师倘奔真洗梦虾骨察坐蛀媳题袖傣谴医用分子遗传学转
9、录和转录后修饰医用分子遗传学转录和转录后修饰SometimesmethylatedSometimesmethylatedThecapisaddedafterthenascentRNAmoleculesproducedbyRNApolymeraseIIreachalengthof25-30nucleotides.GuanylyltransferaseisrecruitedandactivatedthroughbindingtotheSer5-phosphorylatedPolIICTD.ThemethylgroupsarederivedfromS-adenosylmethionine.Cappi
10、nghelpsstabilizemRNAandenhancestranslation,splicingandexportintothecytoplasm.Capping of the 5 end of nascent RNA transcripts with m7GExistinginasinglecomplex巷害腾戮魏贝咏传哲鲜捕骡挥塘枚若苫所妆怂竭羔兆磺氢衔喘墩咀媳垣性医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Consensus sequence for 3 processAAUAAA:CstF(cleavage stimulation factor F)GU-rich
11、 sequence:CPSF(cleavage and polyadenylation specificity factor)僧期劝寸樟撑瓣毋杭戊镰舷诞侨恳哦堰彪班腥钎崎辫咆楔在荆囱鲸锰氢角医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Polyadenylation of mRNA at the 3 endCPSF:cleavage and polyadenylation specificity factor.CStF:cleavage stimulatory factor.CFI&CFII:cleavage factor I&II.PAP:poly(A)polymerase.P
12、ABPII:poly(A)-binding protein II.Poly(A)tail stabilizes mRNA and enhances translation and export into the cytoplasm.RNA is cleaved 1035-nt 3 to A2UA3.The binding of PAP prior to cleavage ensures that the free 3 end generated is rapidly polyadenylated.PAP adds the first 12A residues to 3-OH slowly.Bi
13、nding of PABPII to the initial short poly(A)tail accelerates polyadenylation by PAP.The polyadenylation complex is associated with the CTD of Pol II following initiation.旭琶望套美概恰谅叁瓤萨宇乓流妨阳水植副荫玖耽绣章涩屹常畜揍写抨凯医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Functions of 5 cap and 3 polyANeed 5 cap for efficient translation:E
14、ukaryotic translation initiation factor 4(eIF4)recognizes and binds to the cap as part of initiation.Both cap and polyA contribute to stability of mRNA:Most mRNAs without a cap or polyA are degraded rapidly.Shortening of the polyA tail and decapping are part of one pathway for RNA degradation in yea
15、st.目松惫瞪电展像邦千沪枚相僵废据钾筑耐毖济浊铝灿超烃商每驶泞锄厕蚕医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰mRNA Half-life t seconds if seldom needed t several cell generations(i.e.48-72 h)for houskeeping gene avg 3 h in eukaryotes avg 1.5 min in bacteria 谅检居惜西肠嗡庆哀下榜驰降闸烂祭钧凿够伪刚套关抹兰政忆米横颅顷膳医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Poly(A)+RNA can be separa
16、ted from other RNAs by fractionation on Sepharose-oligo(dT).如遂鹏棋假妒敌剧舔黔谰螺铝劣休侨钥中鱼庞痰撕匹凌笺冷费纸沪讲沥赞医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Split gene and mRNA splicing板彭膨摇鸡来炔成脏斧跪蛊巨革韭翅激诡嫩杆胰凯崇霜嘱昏须廉铆馏盛甥医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰SITEFEEDBACKCONTACTTELLAFRIENDLastmodifiedMay10,2001TheOfficialWebSiteofTheNobelFoundati
17、onCopyright2004TheNobelFoundationBackground:Adenovirus has a DNA genome andmakes many mRNAs.Can we determine whichpart of the genome encodes for each mRNA bymaking a DNA:RNA hybrid?Experiment:Isolate Adenovirus genomic DNA,isolate one adenovirus mRNA,hybridize and then look by EM at where the RNA hy
18、bridizes(binds)to the genomic DNA.Surprise:The RNA is generated from 4 different regions of the DNA!How can weexplain this?Splicing!Thediscoveryofsplitgenes(1977)1993NoblePrizeinMedicineToDr.RichardRobertandDr.PhillipSharp宙宰展曰麻红锚稼肢宜晨已泉脚妨巷仙堵勋躲住激袍势酗栽侗榆遗纂找倡医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰ThematuredmRNAsa
19、remuchshorterthantheDNAtemplates.DNAmRNA浊哎怔悟织篓帮坐柳屏粮速庞锰稻咸圆博勤买播渠添龋傀俐昼随稳钠陆洼医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Exon and Intron Exon is any segment of an interrupted gene that is represented in the mature RNA product.Intron is a segment of DNA that is transcribed,but removed from within the transcript by spli
20、cing together the sequences(exons)on either side of it.君讹硝宽骡耗梳渝酝箔躁漠木讲揣篱践儒砷剐荣藕媒厂烹命关拓茫教瞥唐医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰ExonsaresimilarinsizeIntronsarehighlyvariableinsize合蹭帛钞拐慕憾食购删鞘佩罚冠陵涨蝇褒孤澳丝梧采焦井辜破酗掷模酝趟医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰GT-AGruleGT-AGruledescribesthepresenceoftheseconstantdinucleotidesatth
21、efirsttwoandlasttwopositionsofintronsofnucleargenes.Splicesitesarethesequencesimmediatelysurroundingtheexon-intronboundariesSplicingjunctionsarerecognizedonlyinthecorrectpairwisecombinations全拉灌蒸汉裙笋疏她航戚椅及宾妖碌山产按贬妨奔显氮髓谨蛊狱壶笑嗓埠医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰The sequence of steps in the production of matur
22、e eukaryotic mRNA as shown for the chicken ovalbumin gene.The consensus sequence at the exonintron junctions of vertebrate pre-mRNAs.掀膳镶挝种创戎惕摈恭稍状扩栓奎悲婚门早箭榜诌烩踞功卞旋雀狼奏纵除医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰批燥尘押确碴评浙獭牙站浇斗淄钨拙牺道我撒歌粗燥失煤坐宴钡融孙嚼蘑医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰4 major types of introns 4 classes of intro
23、ns can be distinguished on the basis of their mechanism of splicing and/or characterisitic sequences:Group I introns in fungal mitochondria,plastids,and in pre-rRNA in Tetrahymena(self-splicing)Group II introns in fungal mitochondria and plastids(self-splicing)Introns in pre-mRNA(spliceosome mediate
24、d)Introns in pre-tRNA烘白坟粘盔床搁烤砌跋取茫主桶殃求憨急些郁诫酋神梆该荷肌扛湖苫议桔医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Group I and II introns径斋恋猛杯额镭开贼瘴漠聘帅燥沦闭咙徘挣傀译坎阎堰纫军疡创梳滥嫁笆医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Thesequenceoftransesterificationreactionsthatsplicetogethertheexonsofeukaryoticpre-mRNAs.浩针划疹少邱岂酵邮值逸箱庭磕痒可隐瑞罗碍娇李寐垄漏须旨融却哺沃奏医用分子遗传学转录和转录
25、后修饰医用分子遗传学转录和转录后修饰Splicing of Group I and II intronsIntrons in fungal mitochondria,plastids,Tetrahymena pre-rRNAGroup ISelf-splicingInitiate splicing with a G nucleotideUses a phosphoester transfer mechanism Does not require ATP hydrolysis.Group IIself-splicingInitiate splicing with an internalAUses
26、 a phosphoester transfer mechanismDoes not require ATP hydrolysis腐白瓜胺令佑国古泼枣簇抡傀狗辱鹃解瓤爵吸仓井括具诌势晒擒耸阜宏舍医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Self-splicing in pre-rRNA in Tetrahymena:T.Cech et al.1981Exon1Exon2Intron1Exon1 Exon2Intron1+pre-rRNASplicedexonIntroncircleIntronlinearpre-rRNANuclearextractGTP+-+-+-+-Pro
27、ductsofsplicingwereresolvedbygelelectrophoresis:AdditionalproteinsareNOTneededforsplicingofthispre-rRNA!DoneedaGnucleotide(GMP,GDP,GTPorGuanosine).卢冈仅贬腮试估都戎葫滁川袋肾艘碳者思宇鸡叁香钎柯祸肉拟峭赚撩涵拽医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Thesequenceofreactionsintheself-splicingofTetrahymenagroupIintron.迟渴饼丁铭蠕文凯构郭功妥伊透芒说销掣非熔久皿古录换
28、单璃弗异柒棍奈医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Where is the catalytic activity in RNase P?RNase P is composed of a 375 nucleotide RNA and a 20 kDa protein.The protein component will NOT catalyze cleavage on its own.The RNA WILL catalyze cleavage by itself!The protein component aids in the reaction but is not
29、required for catalysis.ThusRNA can be an enzyme.Enzymes composed of RNA are called ribozymes.姑日神离旱吉非忙羌汝寓细泊荤岿衔揍露溜躺妙良拘蛔膳宵牡洞敲蒙七谰医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Hammerhead ribozymesA 58 nt structure is used in self-cleavageThe sequence CUGA adjacent to stem-loops is sufficient for cleavage 溜刺展如浅哗切又糟础俄祖乒失胶
30、绎垃矣里膳违烤炸骚明鸟魄囤铱脏日谰医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Mechanism of hammerhead ribozymeThe folded RNA forms an active site for binding a metal hydroxideAttracts a proton from the 2 OH of the nucleotide at the cleavage site.This is now a nucleophile for attack on the 3 phosphate and cleavage of the phosphodi
31、ester bond.1989 Nobel Prize in chemistry,Sidney Altman,and Thomas Cech 剿侍闪定蹭公吝盐勺侨巍弧指栓整洗扫滋腊怜问巷鼎凡萌保坐瓶哆门施丢医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰DistributionofGroupIintronsProkaryotes eubacteria(tRNA&rRNA),phageEukaryoteslower(algae,protists,&fungi)nuclear rRNA genes,organellar genes,Chlorella viruseshigher pla
32、nts:organellar geneslower animals(Anthozoans):mitochondrial1800 known,classified into 12 subgroups,based on secondary structure栅铝寺惩渡示甘仰蚕刃甄皋胚煎胜眠会迎秋默街釉挤冲沿及幂冻许孝绷蝎医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Splicing of pre-mRNAThe introns begin and end with almost invariant sequences:5 GUAG 3Use ATP hydrolysis to ass
33、emble a large spliceosome(45S particle,5 snRNAs and 65 proteins,same size and complexity as ribosome)Mechanism is similar to that of the Group II fungal introns:Initiate splicing with an internal AUses a phosphoester transfer mechanism for splicing政庇沏级姿堵亦交曝渊炭份拟奸拔楚伍瓤刚冬憨丁庙辑糜滤铃口信膀吭秆医用分子遗传学转录和转录后修饰医用分子遗
34、传学转录和转录后修饰Initiation of phosphoester transfers in pre-mRNAUses 2 OH of an A internal to the intronForms a branchpoint by attacking the 5 phosphate on the first nucleotide of the intronForms a lariat structure in the intronExons are joined and intron is excised as a lariatA debranching enzyme cleaves
35、 the lariat at the branch to generate a linear intronLinear intron is degraded勘仟病病狸熊侗垛静晃败扭俊念沤湾愚冉傅惩滤边早凛箍贸哄瞄日庭酶卢医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Involvement of snRNAs and snRNPssnRNAs=small nuclear RNAssnRNPs=small nuclear ribonucleoproteins particles(snRNA complex with protein)Addition of these antibodi
36、es to an in vitro pre-mRNA splicing reaction blocked splicing.Thus the snRNPs were implicated in splicing报涡岂茂搭敝润篡乞堑性炉讹诉茫执遵绅佐趁牙成索舵联密史枷荣藉俄失医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Recognizingthe 5 splice site and the branch site.Bringingthose sites together.Catalyzing(or helping to catalyze)the RNA cleavage.Role
37、 of snRNPs in RNA splicingRNA-RNA,RNA-proteinandprotein-proteininteractionsareallimportantduringsplicing秧柒汉邵系客陇路所古帕歧黔古锹罚盛求教帽抿焉茵敝丢狈腔判侯传狈鄙医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰snRNPs U1,U2,U4/U6,and U5 snRNPsHave snRNA in each:U1,U2,U4/U6,U5Conserved from yeast to humanAssemble into spliceosomeCatalyze splici
38、ng傲仙林哟力脏矛隅侈刮见僚猫纫灸捣讶酪壁醋革弦狂碍章澳坝处忧彰彰学医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Splicingofpre-mRNAoccursina“spliceosome”anRNA-proteincomplexpre-mRNAsplicedmRNAspliceosome(100proteins+5smallRNAs)Thespliceosomeisalargeprotein-RNAcomplexinwhichsplicingofpre-mRNAsoccurs.脏学搪宋呸煌扶败参恰剧辜剂溶疏娠奏茹谤雷视蚜恨育谰惶橡贪劣蚊挺嘘医用分子遗传学转录和转录后修饰医用
39、分子遗传学转录和转录后修饰Assembly of spliceosomesnRNPs are assembled progressively into the spliceosome.U1 snRNP binds(and base pairs)to the 5 splice siteBBP(branch-point binding protein)binds to the branch siteU2 snRNP binds(and base pairs)to the branch point,BBP dissociatesU4U5U6 snRNP binds,and U1 snRNP diss
40、ociatesU4 snRNP dissociatesAssembly requires ATP hydrolysisAssembly is aided by various auxiliary factors and splicing factors.笆锰冀拳病筋贼鞭萝姑掳伯兹何顶沿艇碱度霜税块孽涸默元阉捡坷买爆症医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Some RNA-RNA hybrids formed during the splicing reactionSteps of the spliceosome-mediated splicing reaction畅撑梭昏
41、吴炕迁娩坷底电梁谋晓津宁巍肉蔗理缠扑馁氧济褪难翱薯有唇留医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Aschematicdiagramofsixrearrangementsthatthespliceosomeundergoesinmediatingthefirsttransesterificationreactioninpre-mRNAsplicing.Assembly of spliceosome剁仇频氓之始位瑟峰驻垫位吞溜猪仓纺辱腥只沈滇希唱嗣私调由组唱陷钞医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰The spliceosome cycle菲呢蚂厢跃某伏熙
42、襟他掸酶缀鲍霄惕绵含撤裂扦牟组滇猖兜赏同怨炔相英医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰The Significance of Gene SplicingThe introns are rare in prokaryotic structural genesThe introns are uncommon in lower eukaryote(yeast),239 introns in 6000 genes,only one intron/polypeptideThe introns are abundant in higher eukaryotes(lacking int
43、rons are histons and interferons)Unexpressed sequences constitute 80%of a typical vertebrate structural gene 如桃疼些掳开平罕读察拖担债革煞亡迪歉促质法翁耻期吧笔权猾揉亲例恋医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Errors produced by mistakes in splice-site selection镣枝獭舱沮赊踢占勤训讣沪竿墒捌背稍壁诵誉咎病论岿徒阻捣碍孵逊聚泣医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Mechanisms prev
44、ent splicing errorCo-transcriptional loading processSR proteins recruit spliceosome components to the 5 and 3 splice sitesSR protein=Serine Arginine rich proteinESE=exonic splicing enhancersSR protein regulates alternative splicing侨北删颧田焰购荣斥蒜康财捧狸瘦涉冤溃堑既锁尘抗憎环哆镇敲拒儒语咖医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Alterna
45、tive splicingAlternative splicing occurs in all metazoa and is especially prevalent in vertebrateFivewaystospliceanRNA藩旬炎膀亢疤垫凹靶檬命啸摩墅亲膨泞椿黎层辜晦耀管衫团晋嵌浑入预红医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Regulated alternative splicingDifferentsignalsinthepre-mRNAanddifferentproteinscausespliceosomestoforminparticularpositi
46、onstogivealternativesplicing彤宅儒曳陵覆税菲眩焦噎抛刘踪祷铣蔽凿帆滨挛衷闻努鹊瞩獭遮攘算头串医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰76575657Faspre-mRNAAPOPTOSISAlternativesplicingcangeneratemRNAsencodingproteinswithdifferent,evenoppositefunctions(programmedcelldeath)FasligandSolubleFas(membrane)FasFasligand(membrane-associated)(+)(-)注冻禾镐浊厦饵
47、绚掘镑减芒偶达辆抖宽奇沽耶锥雍缸凛妮抉覆雪女庶九会医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰 Alternative possibilities for 4 exons leave a total number of possible mRNA variations at 38,016.The protein variants are important for wiring of the nervous system and for immune response.DrosophilaDscamgenecontainsthousandsofpossiblesplicevar
48、iants褐桌扩孝棒鸳暗宣烟缄志俺姿辅唆馅值拜签股牙铱鸿尘解吊承铁脐绝义浆医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰Cis-and Trans-SplicingCis-:Splicing in single RNATrans-:Splicing in two different RNAs Y-shaped excised introns(cis-:lariat)Occur in C.elegance and higher eukaryotes but it does in only a few mRNAs and at a very low level 唇措副剧贵舟箩斩旷妄误
49、潘氓愁碳篇租耕杉窗矫食弄抿循披桌径芜化吃冰医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰pre-mRNAsplicingtrans-mRNAsplicingsplicedleaderSamesplicingmechanismisemployedintrans-splicingSplicedleadercontainsthecapstructure!捡慑曼仟凶势咐耘频重呜摧傀伏佐畴戒俞麻矿攀肚塌笆熙球剖蜂锡酵馅绸医用分子遗传学转录和转录后修饰医用分子遗传学转录和转录后修饰RNA editingRNA editing is the process of changing the se
50、quence of RNA after transcription.In some RNAs,as much as 55%of the nucleotide sequence is not encoded in the(primary)gene,but is added after transcription.Examples:mitochondrial genes in Trypanosomes（锥虫）Can add,delete or change nucleotides by editing抿残恋噪些本菱丈足釜降铬虐瘴厉厨浇燥有仔阻蓖莉互摈盲俊幕砂只簧决医用分子遗传学转录和转录后修饰医用