Change in transcription patterns during early development of the sea urchin☆

[摘要] ComplementaryDNA(cDNA)probescomplementarytopolyadenylatedmRNAandHnRNAfromseaurchinblastulasweresynthesizedbyreversetranscriptasetoanalyzechangesinprevalentclassRNAduringearlydevelopment.About17%ofA+HnRNAand62%ofA+mRNAistranscribedintothecDNAprobes.AsmeasuredbyRNA-excesshybridization,thecomplexityofcDNAtranscribedfromHnRNAwas4.1±1×107nucleotides,andthecomplexityofcDNAfrommRNAwas6.0±1.2×105nucleotides.Thesevaluescorrespondto12to20%and2to3%ofthetotalblastulaHnRNAandmRNAcomplexity,respectively.ThecDNAthusrepresentsalimitedsubsetofthetotalmRNAsequencesbutasubstantialfractionoftheHnRNAsequences.ThecDNAprobeswerehybridizedwithalargeexcessofthecorrespondingpolyadenylatedRNApopulationsfromgastrulaandpluteusembryos.Plateauvaluesappearedtobesubstantiallylowerfortheheterologousreactions.Thekineticsofthereactionsindicateatwo-tothreefoldreductioninabundanceofHnRNAspeciesthatpersisttogastrulaandafurthersmallreductionatpluteus.TheabundanceofthepersistentmRNAtranscriptsdecreases20-foldatgastrulabutremainsconstantthereafter.

[学科分类] 生物科学（综合）