Slow muscle myoblasts differentiating in vitro synthesize both slow and fast myosin light chains

摘要

Whetherfastandslowskeletalmusclesoftheembryodevelopfromcellsofacommonoriginorfromtwoseparatecellularoriginsisnotknown.Recentevidencesuggeststhatpriortoinnervationallmusclesoftheembryoareofonetype,thefasttype,i.e.,allsynthesizefastbutnotslowmyosinlightchains.Innervationhasbeenthoughttoplaythecentralroleintheshiftofafasttoaslowmuscle.Experimentsreportedheredemonstratethatmyoblastsfromslowmuscleregionsoftheembryowhenisolatedintissueculturedifferentiateintomyotubeswhichsynthesizebothfastandslowmyosinlightchains,andthatinnervationisnotrequiredtoinitiateslowmyosinlight-chainsynthesis.