Multiple oligo(A) tracts associated with inactive sea urchin maternal mRNA sequences☆

[摘要] MaternalRNAofseaurchineggsandembryoswasanalyzedforshortpoly(A)sequencesbydigestinghybridsformedbetween[3H]poly(U)andpoly(A)withRNaseat4°C.Whentheundigested[3H]poly(U)isprecipitatedwithCTAB,all(A)ntractslongerthan6nucleotidesaredetected.Thisassayrevealedapoly(A)contentseveralfoldhigherthanisobtainedwithasimilarassayusingRNaseathighertemperatures.Onpolyacrylamidegelelectrophoresis,mostofthepreviouslyundetected(A)ntractsranasapeakofoligo(A)oflessthan20nucleotideswhichaccumulatedatthedyefront.Theoligo(A)sequenceswereresolvedintoasinglepeakof(A)10whensizedonSephadexG100.These(A)10sequenceswereassociatedwithlargemRNA-sizedmoleculesofabout3000nucloetidesaveragelengthwhichcomprised0.5to2%ofthetotalmaternalRNA.However,the(A)10sequenceswerenotinmRNAmoleculescontaining3′-terminalpoly(A)of50–120nucleotidesnordidtheyremaininRNAthatenteredpolysomesuponfertilization.However,hybridizationstudiesshowedthatallsequencesrepresentedinthematernalpoly(A)-containingRNAappearedtobepresentintheRNAmoleculescontainingonly(A)10sequences.Theresultssuggestthatthe(A)10-containingRNAmightbeincompletelyprocessedmRNAprecursor-likemolecules.

[学科分类] 生物科学（综合）