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miRNA作用机制研究进展.docx

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miRNA作用机制研究进展 Title:AdvancesinResearchontheMechanismsofmiRNAAction Introduction: MicroRNAs(miRNAs)aresmallnon-codingRNAmoleculesthatplayacrucialroleinpost-transcriptionalgeneregulation.Theyhavebeenfoundtobeinvolvedinvariousbiologicalprocesses,includingcelldevelopment,differentiation,andapoptosis.UnderstandingthemechanismsofmiRNAactionisessentialforgaininginsightsintogeneregulationanditsimplicationsindiseasedevelopment.Inthispaper,wewillprovideanoverviewoftherecentadvancesintheresearchonthemechanismsofmiRNAaction. miRNABiogenesisandMaturation: ThebiogenesisofmiRNAsinvolvesaseriesofwell-coordinatedsteps.Initially,primarymiRNAs(pri-miRNAs)aretranscribedbyRNApolymeraseIIorIII.Thesepri-miRNAscontainstem-loopstructures,whicharerecognizedandcleavedbytheRNaseIIIenzyme,Drosha,togetherwithitscofactor,DGCR8,toproduceprecursormiRNAs(pre-miRNAs).Pre-miRNAsarethenexportedfromthenucleustothecytoplasmbytransportin-5(TRN-5)andsubsequentlyprocessedintomaturemiRNAsbytheRNaseIIIenzyme,Dicer.ThematuremiRNAsareincorporatedintotheRNA-inducedsilencingcomplex(RISC)andguidethecomplextotargetmRNAsthroughsequencecomplementarybasepairing,leadingtomRNAdegradationortranslationrepression. TargetRecognitionandEffectonGeneExpression: miRNAsexerttheirregulatoryfunctionspredominantlythroughbasepairingbetweenthemiRNAseedregion(positions2-8)andthe3'untranslatedregion(UTR)oftargetmRNAs.ThisbindingleadstoeitherdegradationofthetargetmRNAorinhibitionofitstranslation.RecentstudieshaverevealedthatmiRNAsmayalsobindtootherregionsofthetargetmRNA,suchasthecodingsequenceorthe5'UTR,resultinginadditionalmodesofgeneregulation.Furthermore,ithasbeendiscoveredthatmiRNAscanalsotargetothertypesofRNAmolecules,includinglongnon-codingRNAsandcircularRNAs,expandingtheirregulatorycapabilities. RegulationofmiRNAExpressionandActivity: TheexpressionandactivityofmiRNAsaretightlyregulatedatmultiplelevels.TranscriptionfactorsandepigeneticmodificationsplaycrucialrolesincontrollingmiRNAexpression.Additionally,post-transcriptionalmodifi