Changing rates of DNA and RNA synthesis in Drosophila embryos
[摘要] RatesofDNAandRNAsynthesisduringDrosophilaembryogenesisweremeasuredbylabelingoctane-treatedembryoswith[14C]thymidineand[3H]uridine.Radioactivityincorporatedperhourwasconvertedtoratesofsynthesisusingmeasurementsofthepool-specificactivityduringthelabelingperiods.TherateofDNAsynthesisduringearlyembryogenesisincreasestoamaximumat6hrafterovipositionandthendecreasessharply.MeasuredratesofDNAsynthesiswereusedtocalculatethatthetotalamountofDNAperembryodoublesevery18minatblastoderm,every70–80minduringgastrulation,andlessthanonceevery7hratlaterstages.TherateofRNAaccumulationperembryoincreasescontinuouslyduringthefirst14hrofembryogenesis.TherateofnuclearRNAsynthesisperdiploidamountofDNA,however,decreasesfivefoldbetweenblastodermandprimaryorganogenesis.Thecytoplasmicpoly(A)+RNAsynthesizedbyblastodermembryosassociatesrapidlywithpolysomes.Therelativelyhighrateofsynthesisofpolysomalpoly(A)+RNApernucleusatblastodermallowsthesmallnumberofnucleipresentatblastodermtomakeasignificantquantitativecontributiontotheinformationalRNAactiveintheearlyembryo.Attheendofblastoderm,approximately14%ofthemRNAbeingtranslatedintheembryohasbeensynthesizedafterfertilization.
[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]
