Developmental appearance of myosin heavy and light chain isoforms in vivo and in vitro in chicken skeletal muscle☆

[摘要] Threemyosinheavychainisoformswithuniquepeptidemapsappearsequentiallyinthedevelopmentofthechickenpectoralismajormuscle.Anembryonicisoformisexpressedearlyandthroughoutdevelopmentintheembryo.Asecondisoformappearsjustafterhatchingandpredominatesby10daysexovo.Athirdisoform,indistinguishablefromadultmyosinheavychain,predominatesby8weeksafterhatching.Thissequenceofmyosinisoformchangedoesnot,however,appearduringmyogenesisinvitro.Inculturespreparedfromembryonicmyoblastsonlyembryonicmyosinheavychainisexpressed.Thisistrueeveninculturesmaintainedfor30days.Myosinlightchainexpressionalsochangesinvivowithaprogressiveincreaseinfastlightchain3accumulation.Invitro,however,thisshifttoincreasingfastlightchain3accumulationdoesnotoccur.Theresultsindicatethatthemyosinheavychainandlightchainpatternobservedinvitroisidenticaltothatoftheembryonicmuscleandthattheconditionsnecessaryfortheshiftinexpressiontoamorematuremyosinphenotypearenotpresentinmyogeniccultures.Theseculturesarethereforepotentiallyofgreatvalueinprobingfurthertheneuralandhumoraldeterminantsofmusclefibermaturationandgrowth.

[学科分类] 生物科学（综合）