Fertilization of sea urchin eggs is accompanied by 40 S ribosomal subunit phosphorylation☆
[摘要] Afterfertilizationofseaurchin(Arbaciapunctulata)eggs,thereisasingleprominentalterationinthepatternofproteinphosphorylation.Ineggspreloadedwith32PO4,a31,000Mrprotein(rp31)becomeslabeledwithin4minofspermaddition.Anewsteady-statelevelofrp31labelingisachievedby11min.Therateofproteinsynthesisinseaurchinzygotesalsoincreasesat8–10minafterfertilization.Proteinrp31correspondstomammalianribosomalS6becauseitcosedimentswith40Ssubunitsonhighsalt-sucrosegradients,itissimilartothemammalianproteininMrandcharge,anditbecomesphosphorylatedduringanincreaseinproteinsynthesis.Thespecificactivityofphosphorylatedrp31(relativetorRNA)issimilarbetweenfree80Smonosomesandpolysomes,indicatingthatrp31phosphorylationisnotsufficientforribosomalactivity.Aphosphatase,highlyspecificforrp31,ispresentinextractsofeggsandveryearlyembryos.Thisphosphatasebecomesinactiveataboutthesametimethatthedegreeoflabelingofrp31increasesinembryos.Evidentlyacontrolsystemthatmaintainsalowlevelofrp31phosphorylationisactiveinseaurchineggs.Inactivationofthissystemshortlyafterfertilizationleadstotheaccumulationofphosphorylatedribosomes.
[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]
