Clonal analysis of vertebrate myogenesis: I. Early developmental events in the chick limb☆
[摘要] Earlydevelopmentaleventsoccurringintheprospectivemuscletissueregionofchickembryolegbudshavebeensubjectedtoaninvitroclonalanalysis.Colony-formingcellsarepresentatstage20(72hrincubation),butnoneofthecoloniesexhibitmorphologicalsignsofmuscledifferentiation.Afteranadditional8hrofincubation(stage21),approximately10%ofthecolony-formingcellshaveacquiredthecapacitytoformmultinucleatedcellsinvitro,andthepercentageofclonablemyoblastsincreasestoalevelofapproximately60%duringthenext3daysofincubation.Clonalanalysisofmyoblastpopulationswithinregionsofthedevelopinglimbhaveindicatedthat,betweenstages21and27,thedorsalandventralsegmentsofthemyogenicregioncontainappreciablymoreclonablemusclecellsthantheanteriorandposteriorsegments.Inaddition,duringstages21and22thereisa3-folddifferenceinmuscle-colony-formingcellsbetweentheproximalanddistalhalvesofthedorsal-ventralsegments,aswellasbetweentheproximalanddistalhalvesoftheanterior-posteriorsegments.Thusatleasttwotemporalandregionalgradients—proximaltodistalandmedialtolateral—ofclonablemyoblastcontentcanbedelineatedwithinthedevelopingchicklimb.Inadditiontochangesintheproportionsofmuscle-colony-formingcells,theextentofmultinuclearitywithinindividualmusclecoloniesincreaseswiththedevelopmentalageoftheembryofromwhichtheclonablemyoblastsarederived.Theprogressivechangesintherelativeproportionsofmuscle-colony-formingcellsandinclonalmorphologyarediscussedintermsoftheirpossiblecelllineageimplications.
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[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
