Polyadenylated and nonpolyadenylated messenger RNA fractions from sea urchin embryos code for the same abundant proteins☆

[摘要] RNAwasextractedfrompolysomesofseaurchinmesenchymeblastulasandfractionatedbyaffinitychromatographyonoligo(dT)-cellulose.Thepoly(A)+andpoly(A)−fractionsweretranslatedincell-freesystemsderivedfromwheatgermandrabbitreticulocytes.Thetranslationproductswereanalyzedbytwo-dimensionalelectrophoresisonpolyacrylamidegelsandfoundtobequalitativelysimilarforpoly(A)+andpoly(A)−mRNA.Mostoftheproductsofcell-freetranslationhavebeenidentifiedamongtheinvivotranslationproducts,indicatingthefidelityofthetranslationsystems.Atleast85%ofthepoly(A)−mRNAlacksdetectable(8nucleotidesorlonger)tractsofpoly(A).Lessthan11%ofthepoly(A)−mRNAenteringpolysomesinthereticulocytelysatecontainsdetectablehomopolymersofadenosine.Weconcludethatthepoly(A)+andpoly(A)−mRNAcodeforthesamesetofabundantproteins,havingisoelectricpointsbetween5and7.2andmolecularweightsbetween15,000and100,000.Itispossiblethatsomeproteins,suchashistones,notdetectableinouranalysisarecodedforexclusivelybymRNAhavingorlackingpoly(A)tracts.

[学科分类] 生物科学（综合）