分子生物学课程作业 microRNA.docx

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1、分子生物学课程作业分子生物学研究的新领域——microRNATheNewAreaInMolecularBiology——MicroRNAAbstractSincethefirstdiscoveryofmicroRNAin1993byVictorAmbros,RosalindLeeandRhondaFeinbaumduringastudyofthegenelin-14inC.elegansdevelopment.,microRNAhasattractedmuchattentionglobally.micro

2、RNAsareagroupofnon-codingRNAsfoundinplantsandanimalswhichfunctionstoregulategeneexpressiontranscriptionallyandpost-transcriptionally.UsuallybyforminginaRISC(RNA-inducedsilencingcomplex),microRNAscanbindspecificallytoitsbase-pairingtargetRNAsites,causingas

3、pecificgenesilencingbyexpressionrepressionandtargetdegradation.Thehumangenomemayencodeover1000microRNAs,whichmaytargetabout60%ofmammaliangenesandareabundantinmanyhumancelltypes.Recentresearcheshavefocusedonitsevolutionaryfunctions,researchersholdtheviewth

4、atmicroRNAplaysessentialrolesingenefine-tuningandgenecanalization,whichmeansmicroRNAgenecouldbeviewedasaevolutionmarkeramongspecies.ThemicroRNAregulationsystemprovidesanewperspectiveinfindingaproperandeffectivemethodtosomedeadlydiseases.Meanwhile,themicro

5、RNAhasbeenaintriguingresearchareabecauseofitsuniquecharacteristics:itisthefirstandonlyknowneukaryoticgenesbyfarthataretranscribedasapolycistron,whichwasthoughttobeonlyexistinginprokaryoticorganisms.Thishasledtheresearchtoitsgeneclusterlevel.We’vedefinedfo

6、ur2modelsfortheemergenceofmicroRNAgenecluster:de-novoemergenceandgeneduplication.Butwe’restillinterestedintheinnermechanismthatmotivatesthewholegeneclustertoevolve:whataretheinnerrelationshipbetweenthemicroRNAgenesthatcoexistinonecluster?Weproposethatther

7、e’sa“drift-draft”effectbetweenthegenesandwe’vedesignedsomestrategiestoprovethiseffect.FurtherresearchmayconcentrateonthestabilityofaregulationnetworkmaintainedbymicroRNA,andthecomplicatemechanismofinteractionsoftranscriptionfactors,microRNAgeneexpressiona

8、ndtargetgenedegradation,whichmayprovideapotentialtoolinunderstandingphylogenesisandcuringdiseases.MicroRNA是一种在真核生物钟广泛存在的RNA分子，长约21~23nt左右，这种RNA分子的特别之处在于其可以在转录水平上对真核基因的表达起到调节作用，这种调节作用不仅仅发生在正常的组织器官中，而且也发生在发生病变的组织和器官中，