Most sea urchin maternal mRNA sequences in every abundance class appear in both polyadenylated and nonpolyadenylated molecules☆

[摘要] Thesequencesinpoly(A)-containingand-deficientRNAaccumulatedinseaurchineggswereanalyzedbyhybridizationtocDNAandsingle-copygenomicDNA.Thereactionofpoly(A)eggRNAtoitshomologouscDNAoccursoverfiveordersofR0t.Astandardcomputerfittothereactioncurvesindicatesthreeabundanceclasseswith32%ofthepoly(A)RNAinhighlyabundantsequences,13%inmoderatelyabundantsequences,and55%inraresequences.Thecalculatednumberofaveraged-sized,3000-nucleotide-longmRNAsequencesineachoftheseclasseswas2,44,and4600,respectively.ReactionsofcDNAtototalandpoly(A)-deficientRNAindicatethatlessthanhalfofthemoleculescontaininganyindividualsequencecarriedapoly(A)segmentlargeenoughtobindtooligo(dT).Asaturationhybridizationtosingle-copyDNAcomplementarytoeggRNAindicatedthatallrareclasssequencesarepolyadenylated.Aboutone-thirdareadenylatedon30to50%oftheirmolecules;theremainingraresequencesarepolyadenylatedonabout5%oftheirmolecules.Mostsequencespresentinpoly(A)RNAmoleculesintheeggarefoundassociatedwithpolysomesfollowingfertilization.About80to85%ofthepoly(A)maternalmRNAsequencesincDNAwhichreannealtototalseaurchinDNAreactas-single-copysequences,while15to20%reactasrepetitiveDNAsequences.

[学科分类] 生物科学（综合）