The correlation of DNA synthesis and DNA polymerase activity in the developing chick heart☆
[摘要] NetDNAsynthesiscontinuesthroughouttheembryonicdevelopmentofchickventriculartissuebuttherateofDNAaccumulationdeclinesduringtheperinatalperiod.ThisslowingofDNAaccumulationisparalleledbyadecreasedcapacityofchickventricularslicesandofperfusedwholeheartstoincorporate3H-thymidineintoDNA.SynthesisofDNAbyslicesandwholeheartsiscompletelyinhibitedbycytosinearabinoside(ara-C).AtleasttwoclassesofDNApolymerasewhicharedependentuponexogenousDNAhavebeenmeasuredinthe100,000gsuppernatantfractionofchickventricularhomogenates.Thepredominantpolymerase,activewithadenaturedDNAprimer,exhibitsadeclineinactivitywhichiscorrelatedwiththefall-offinDNAsynthesisinventriculartissue.TheactivityofasecondDNApolymerase,activewithanativeDNAprimer,remainsconstantthroughoutthedevelopmentalstagesexamined.ThedecreaseinpolymeraseactivitywithadenaturedDNAprimercannotbeascribedtosolubleinhibitorsofthepolymeraseortodetectableDNaseactivityinoldermyocardialtissue.Severalcharacteristicsofthecrudeenzymehavebeenexamined,includingprimerandsubstratedependence,glycerolandmagnesiumionoptima,andenzymeinhibitionwithN-ethylmaleimide(NEM)and1-β-d-arabinofuranosylcytosinetriphosphate(ara-CTP).PolymeraseactivitywithdenaturedandnativeDNAprimersisdifferentiallysusceptibletothesereagents.
[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]
