pre-mRNA的剪切.ppt

关于pre mRNA的剪切Jovenhaha YigongShi Ph D施一公教授UniversityProfessorSchoolofLifeSciencesTsinghuaUniversityTel lab 86 10 62797560Tel asst 86 10 62781053 TheTeam TheTeam TheSHIlaboratorycombinesstructuralbiology biochemicalandbiophysicalapproachestoelucidatethemolecularandchemicalbasisoffundamentalcellularevents Geneexpressioninalleukaryotesconsistsofthreeessentialsteps transcriptionofDNAintopre mRNA splicingofpre mRNAintomaturemRNA andtranslationofmaturemRNAintoprotein ThesestepsconstitutethecoreprincipleofCentralDogmainmolecularbiology Eachpre mRNAcontainsadistinctnumberofthecodingexonsandtheinterveningnon codingintrons eachwithavaryinglengthanduniquesequence Aberrantsplicingcontributestonumerousdebilitatingdiseases Research Splicingofpre mRNAisexecutedbythespliceosomes whichconsistoffivesmallnuclearribonucleoproteinparticles snRNPs andalargenumberofassociatedenzymesandcofactors Thespliceosomeexhibitsexceptionalcompositionaldynamicsandconformationalflexibility consistentwithitsfunctionofsplicingintronswithdiversesequences Theyhavedeterminedthethree dimensionalstructureofaSchizosaccharomycespombespliceosomeat3 6 resolutionandelucidatedthestructuralbasisofpre mRNAsplicing Science 349 1182 91 2015 Science 349 1191 8 2015 Research TheresolvedyeastspliceosomecontainsU2snRNP U5snRNP nineteencomplex NTC NTCrelatedcomplex NTR U6snRNA andanRNAintronlariat Theatomicmodelincludes10 574aminoacidsfrom37proteinsand4RNAmolecules withacombinedmolecularmassofapproximately1 3mega Daltons Research Inthestructure U5snRNPactsasacentralscaffoldontowhichU6andU2snRNAsareintertwinedtoformacatalyticcenternexttoLoopIofU5snRNA ThecatalyticmagnesiumionsarecoordinatedbyconservednucleotidesinU6snRNA TheintronlariatisheldinplacethroughbasepairinginteractionswithbothU2andU6snRNAs Thus thespliceosomeisinessenceaprotein directedribozyme withtheproteincomponentsessentialforthedeliveryofcriticalRNAmoleculesintocloseproximityofoneanotherattherighttimeforthesplicingreaction Research 2016RuixueWan ChuangyeYan RuiBai LinWang MinHuang CatherineC L Wong YigongShi 2016 The3 8 structureoftheU4 U6 U5tri snRNP Insightsintospliceosomeassemblyandcatalysis Science 6272 466 75 Epub2016Jan7 2015MengyingZhou1 YiniLi1 QiHu1 Xiao chenBai WeiyunHuang ChuangyeYan SjorsH W ScheresandYigongShi 2015 Atomicstructureoftheapoptosome mechanismofcytochromec anddATP mediatedactivationofApaf 1 Genes Dev 2015 29 2349 2361 Xiao chenBai EesonRajendra GuanghuiYang YigongShi SjorsHWScheres 2015 Samplingtheconformationalspaceofthecatalyticsubunitofhuman secretase eLife 10 7554 eLife 11182JingHang RuixueWan ChuangyeYan YigongShi 2015 Structuralbasisofpre mRNAsplicing Science 349 6253 1191 1198 ChuangyeYan JingHang RuixueWan MinHuang CatherineC L Wong YigongShi 2015 Structureofayeastspliceosomeat3 6 angstromresolution Science 349 6253 1182 1191 Xiao chenBai ChuangyeYan GuanghuiYang PeilongLu DanMa LinfengSun RuiZhou SjorsH W Scheres YigongShi 2015 Anatomicstructureofhuman secretase Nature 525 7568 212 217 LinfengSun LingyunZhao GuanghuiYang ChuangyeYan RuiZhou XiaoyuanZhou TianXie YanyuZhao ShenjieWu XuemingLi YigongShi 2015 Structuralbasisofhuman secretaseassembly ProcNatlAcadSciUSA 112 19 6003 6008 ShangyuDang ShenjieWu JiaweiWang HongboLi MinHuang WeiHe Yue MingLi CatherineC L Wong YigongShi 2015 CleavageofamyloidprecursorproteinbyanarchaealpresenilinhomologuePSH ProcNatlAcadSciUSA 112 11 3344 3349 YuxuanPang Xiao chenBai QiHao ChuangyeYan ZheqinChen Jia WeiWang SjorsH W Scheres YigongShi 2015 Structureoftheapoptosome mechanisticinsightsintoactivationofaninitiatorcaspasefromDrosophila GenesDev 29 3 277 287ZhenYan Xiao chenBai ChuangyeYan JianpingWu ZhangqiangLi TianXie WeiPeng Chang chengYin XuemingLi SjorsH W Scheres YigongShi NiengYan 2015 StructureoftherabbitryanodinereceptorRyR1atnear atomicresolution Nature 517 7532 50 55 Publications Prof Dr ReinhardL hrmann Prof Dr ReinhardL hrmannMaxPlanckInstituteforBiophysicalChemistry G ttingen 马克斯 普朗克生物物理化学研究所 哥廷根 Phone 49551201 1407Fax 49551201 1197Email reinhard luehrmann mpi bpc mpg de ReinhardL hrmannisdirectoroftheDepartmentofCellularBiochemistryattheMaxPlanckInstituteforBiophysicalChemistryinG ttingen AfterobtaininghisPhDfromtheUniversityofM nsterandcarryingoutpost doctoralworkattheMaxPlanckInstituteofMolecularGeneticsinBerlin heheadedanindependentMaxPlanckresearchgroupattheOttoWarburgLaboratoryinBerlin From1988to2000hewasProfessorofMolecularBiologyattheUniversityofMarburg ReinhardL hrmannhasmadeseminalcontributionstoourunderstandingofthebiochemistryandnucleo cytoplasmictransportofUsnRNPs andthestructureandfunctionofthespliceosome ReinhardL hrmannhasservedoneditorialboards includingthoseofRNAandtheEMBOJournal asdirectorandpresidentoftheRNASociety andheisanelectedmemberofEMBOandtheGermanAcademyLeopoldina MajorResearchInterests Mostmetazoanpre mRNAscontainmultipleintronsandexons InordertogeneratematuremRNA theintronsmustbeexcisedfromthepre mRNA aprocesstermedpre mRNAsplicing Inmanycases alternativesplicinggeneratesdifferentmRNAsfromasinglepre mRNAbytheregulatedremovalofdifferentsectionsoftheRNA aprocesswhichgreatlyexpandsthecomplexityoftherepertoireofproteinsthatcanbeexpressedfromrelativelysmallgenomes Splicingiscatalysedbyalargemacromolecularmachine termedthespliceosomewhichconsistsofthesmallnuclearRNAs U1 U2 U4 U5andU6 andmorethan150proteins 50ofwhichareassociatedwiththesnRNAstoformsnRNPs Inhislaboratory intenseeffortsarefocussedonunderstandinghowthespliceosomerecognizesandbindstheintronendsanddiscriminatesthemfromexons Thisisanespeciallyconfoundingprobleminmetazoansbecause incontrasttolowereucaryotessuchasyeast pre mRNAintronsareoftenextremelylong 104 105nucleotides whileexonsaregenerallysmall lessthan300nucleotides Anothermajorgoaloftheirresearchistheelucidationofthemechanismsbywhichthespliceosomeassemblesintoacatalyticallyactivemachineandcatalysesintronexcision Finally theyareinvestigatingthe3DstructureofpurifiedspliceosomesormajorbuildingblocksthereofusingelectronmicroscopicapproachesandXraycrystallography Theirstudiesontheregulatorymechanismsofconstitutiveandalternativepre mRNAsplicinginvolvemainlymammaliansystems Asthebasicmechanismsofsplicingcatalysisappeartobeevolutionarilyhighlyconserved theyarealsotakingadvantageofmoleculargeneticapproachesinbakersyeasttoelucidatethestructureandfunctionofthecatalyticcoredomainofthespliceosome Theproductionofproteinsinthecellsofhigherorganismsisacomplexprocessinvolvingmanysteps First thegeneticinformationforaproteinisrewrittenfromDNAintoaworkingcopy theprecursormessengerRNA premRNA However pre mRNAscontainregionsthatdonotcontaininformationusedfortheproductionofproteins theso called introns Theseregionsmustbepreciselycutoutandtheremainingregions whichcontainusableinformation the exons linkedtogether Thismaturationprocessistermed pre mRNAsplicing OnlymaturemRNAs thataretransportedfromthecellnucleusintothecytoplasm canbeusedbytheribosomeasatemplatefortheproductionofproteins Thepresenceofexonsandintronsisagreatadvantageforanorganism asdifferentcombinationsofexonsfromagivenpre mRNAspeciescanbechosentobeincludedinthematuremRNAproduct Inthisway mRNAscorrespondingtomanydifferentproteinscanbemadefromasinglegene Thisso calledalternativesplicingrepresentsanadditionallevelatwhichgeneexpressioncanberegulated Thisexplainswhyhumansmanagewithonlyjustover20 000protein encodinggenesintheirgenomes Understandingsplicingatthemolecularlevelisofgreatmedicalrelevance asaberrantpre mRNAsplicingisthebasisoraseveritymodifierofaplethoraofhumandiseases Thepre mRNAsplicingreactiontakesplaceintwosteps Bothinvolvephosphoester transferreactions andbotharecarriedoutbyamacromolecularmachine thespliceosome Spliceosomesconsistofwellover100proteinsandfivesmallRNAmolecules thesnRNAsU1 U2 U4 U5andU6 andthusconsistlargelyofprotein Manyofthespliceosome scomponentsareorganisedintosmaller stablesub complexes Forexample about50ofthespliceosomalproteinsarestablyboundtothesnRNAs formingRNA proteinparticles termedsmallnuclearribonucleoproteinsorsnRNPs whichincludetheU1andU2snRNPsandtheU4 U6 U5tri snRNP TheMaxPlanckSocietyisGermany smostsuccessfulresearchorga