Studies of muscle development: I. Changes in cell proliferation☆

[摘要] Thenumberofproliferatingcellsandthedurationofthephasesofthereplicationcyclehavebeendeterminedautoradiographicallyinthecellpopulationofthedevelopingchicklegmuscleandpectoralisduringthetransitionfromahighproliferativelevel(7daysofincubation)toalowproliferativelevel(8daysposthatching).InthelegmusclethepercentageofcellsintheDNAsyntheticphasewasfoundtodeclinefrom40%toabout5%and0.8%fordays7and18ofincubationandday8posthatching,respectively.Thecorrespondingfiguresforcellsinmitosiswas1.7%,0.2%,andlessthan0.02%(5daysposthatching)forthelegmusculatureand69%,15%,and3%forthetotalnumberofproliferatingcells.Inthepectoralisthedeclineinallindicesofproliferationwasmuchsmallerduringtheposthatchingperiod.ThedurationoftheDNAsyntheticphaseonbothdays9and16ofincubationwasfoundtobe5.9hours.Forbothdaysthedurationofthesumofpostsyntheticandmitotic(G2+12M)phaseswas1.8hours.Thepresynthetic-postmitotic(G1)phaseincreasedfrom4hoursto9hoursduringdevelopmentfromday9to16.AfurtherincreaseinthedurationofboththeDNAsyntheticphaseandthepostmitotic-presyntheticphasewasalsoindicatedduringdevelopmentafterhatching.Theobserveddataprovideabasisforfutureinterpretationofsyntheticprocessesoccurringduringdifferentiationofmusclecells.

[学科分类] 生物科学（综合）