DNA synthesis, mitosis, and differentiation in cardiac myogenesis☆

[摘要] Cardiacmusclecellsobtainedbytrypsinizing5-daychickembryonicheartwereculturedassinglecellsinseparateculturedishes.Usingthistechnique,problemsofheterotypiccellinteractions,“overgrowth”ofonecelltype,etc.,areeliminated.Experimentsperformedonthesesinglecellculturesshowthatthemusclecellsintheembryonicchickheartsdifferinmorphology,includingcontentofcross-striatedmyofibrils;inabilitytosynthesizeDNAandundergomitosis;andinfrequencyofcontraction.Contractingcellscontainingcross-striatedmyofibrilsundergomitosisinvitro,givingrisetospontaneouslybeatingdaughtercells.Thesedaughtercellscontaincytoplasmicfibrils,whichbindfluorescein-labeledantimyosinimmediatelyaftercytokinesis.Somecardiacmusclecellsfrom5-dayheartdonotdivideinculture;therestundergo1–5doublings.Thispreliminaryinvestigationsuggeststhatthenewmusclecellsformedduringcardiacgrowtharederivedfrommitoticallyactive“overtly”differentiatedcardiacmusclecells.

[学科分类] 生物科学（综合）