Induction of DNA synthesis in amphibian erythroid nuclei in Rana eggs following conditioning in meiotic oocytes☆☆☆

[摘要] ErythrocytenucleifromadultRanapipienswereinjectedintothecytoplasmofdiploteneoocytes,whichwerethenstimulatedtomatureinvitrowithprogesterone.Thirtypercentofthenucleitransformedintocondensedchromosomesalignedonmetaphasespindles.Afterthematuredoocyteswereactivatedparthenogenetically,56%ofthenucleienlargedandtransformedintopronucleiandover75%synthesizedDNA.Alargerpercentageofadulterythroblastnucleirespondedinasimilarfashion.Theseinducedchromosomalandnuclearchangesofinjectednucleisimulatedtheeventsoccurringintheoocyte'sownnucleus.Sinceonly0.1%oferythrocytenucleisynthesizedDNAinvitroandonly24%didsoinalimitedwayafterinjectionintoeggs,wesuggestthatthecytoplasmofmeioticoocytescontainsmolecularfactorswhichactonthechromatinofnoncyclingandterminallydifferentiatederythrocytenucleiandpreparethemtorespondtoactivatedeggcytoplasmwheretheyareinducedtosynthesizeDNA.Theseresultsindicatethatconditioninginmeioticoocytecytoplasmmayenhancethegeneticanddevelopmentalpotentialofnucleifromspecializedcells.

[学科分类] 生物科学（综合）