Transcription, processing, and turnover of RNA from the Drosophila mobile genetic element copia☆
[摘要] Wehaveinvestigatedthetranscription,processing,andsizedistributionofcopianuclearRNAinDrosophilaculturedcellsinordertocharacterizethestepswhichresultinthehighconcentrationofcytoplasmiccopiaRNA.Ninety-fivepercentofpulse-labeled(5min)copianuclearRNAis5kborshorter.Thisisconsistentwiththepreviouslydeterminedabsenceofinterveningsequence(s)inthecopiageneandindicatesthatthereislittletranscriptionofcontiguousregions5′or3′tothecopiasequence.Inpulse-chaseexperiments,weobservedthatonly10%orlessofthelabeledcopianuclearRNAcouldbechasedintothecytoplasm.Continuouslabelingexperiments,analyzedbytakingintoaccountchangingnucleotideprecursorpoolspecificactivitiesduringlabelingandfittingthedatasimultaneouslytoaseriesofdifferentialequations,gaveresultsconsistentwiththepulse-chaseexperiments.Thedata,whetheranalyzedaccordingtoaone-steporatwo-stepprocessingmodel,indicatedthattotalcopianuclearRNAisprocessedtopoly(A)+cytoplasmicRNAwithanefficiencyofonly7%.Inthefittothetwo-stepprocessingmodel,only7%ofthepoly(A)+copianuclearRNAisexportedtothecytoplasm;theremainderturnsoverinthenucleus.Thepoly(A)+copianuclearRNAisdiscreteinsize,incontrasttopoly(A)−copianuclearRNA,whichisheterogeneousinsize.WediscusstheimplicationsoftheseobservationsforthemechanismofintranuclearprocessinganddecayofcopiaRNA.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
