Regulatory mechanisms in the induction of glutamine synthetase in the embryonic retina: Immunochemical studies☆
[摘要] Theprecociousinductionofglutaminesynthetase(GS)byhydrocortisoneinembryonicchickneuralretinatissueinvitrowasstudiedbyimmunochemicalprocedures.TherateofGSsynthesiswasfollowedinculturespulse-labeledfor15minatvarioustimesafterthebeginningofinduction,bymeasuringtheprecipitationwithanti-GSserumofradioactivelylabeledenzyme.TheinducedaccumulationofGSactivitywasfoundtobeduetoprogressiveincreaseintherateofenzymesynthesis,nottocessationofenzymeturnoverortoactivationofpreformedenzymeprecursors.ThedataareconsistentwiththeviewthattheinducedincreaseintherateofGSsynthesisisduetoaccumulationofactiveRNAtemplatesfortheenzyme.TherequirementforcontinuedpresenceoftheinduceronaccumulationofGSactivityandontherateofitssynthesiswerestudiedinculturesfromwhichtheinducerwaswithdrawnsimultaneouslywithcompleteandpartialinhibitionofRNAsynthesis(withactinomycinD).TheresultsindicatethatintheabsenceoftheinducertheexpressivityofpreformedmRNAforGSissuppressedandthattheinducerpreventsthisindirectlybyelicitingtranscriptionofshort-livedregulatoryRNA(desuppressor).AhypotheticalmodelforregulatoryeventsinGSinductionisdescribedanddiscussedintermsoffurtheranalysisofthissystem.
[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]
