Ribosomal RNA synthesis in pre- and post-gastrula-stage sea urchin embryos☆

[摘要] TherateofribosomalRNAsynthesishasbeenmeasuredinseaurchinblastulaeandgastrulaeQuantitationwaseffectedbymeasuringthekineticsofincorporationofmethyl-labeledmethionineintoS-adenosylmethionineandtransferofmethylgroupstocharacteristic2′-O-methylateddinucleotideandtrinucleotidelocationsinribosomalRNA.Weascertainedthatthismethylationrepresenteddenovosynthesis,throughacomparisonofthelabelingoftheseoligonucleotideswith[32P]orthophosphate.TheearlyblastulaandlategastrulaofStrongylocentrotuspurpuratusbothsynthesize40moleculesofnuclearpreribosomalRNAperminutepercell.InLytechinuspictustheblastulasynthesizes16andthegastrula23moleculesperminutepercell.Thereforeneitheraretheribosomalgenesquiescentpriortogastrulationnorisanenhancementoftheirtranscriptionanecessaryconcomitanttogastrulation.Theredoes,however,appeartobeanincreaseintherateofprocessingofnuclearpreribosomalRNAtocytoplasmicribosomesjustpriortoorconcomitantwithgastrulation.

[学科分类] 生物科学（综合）