Specific changes in cellular glycoproteins and surface proteins during myogenesis in clonal muscle cells☆

[摘要] ThecellsurfaceofG8-1clonalmusclecellswaslabelledatdifferentstagesofmyogenesisbyavarietyofmethods.Lactoperoxidase-catalysediodinationrevealedfivesurfaceproteinsof205K(daltons),160K,70K,64K,and53Kwhichwereexpressedonmyoblastcellsonly.Fourcomponentsof150K,140K,54K,and36Kwereexpressedinmyotubeculturesonly.Labellingofcell-surfacesialoglycoproteinsbyperiodate-tritiatedborohydridedetectedthesamefourmyotube-specificcomponentsof150K,140K,54K,and36Kthatwerelabelledbylactoperoxidaseiodination.Cellularglycoproteinexpressionduringmyogenesiswasdetectedbystainingpolyacrylamidegelsofseparatedmusclecomponentswith125I-concanavalinA(ConA)or125I-wheatgermagglutinin(WGA).125I-ConAidentifiedsevenglycoproteinsofmolecularweights,89K,76K,74K,61K,52K,35K,and27K,whichweresynthesisedinmyoblastsandinmyotubesatanearlystageofdifferentiationandwhosesynthesiswasthenswitchedoff.125I-WGAdetectedamyoblast-specificglycoproteinof100Kandaglycoproteinof89Kwhichwasnotsynthesisedinmaturemyotubes.Fibronectinwaslabelledbyeachofthefourprobesandasimilarpatternofregulationwasfoundwitheach.Fibronectinissynthesisedinlowamountsinmyoblasts.Itslevelincreaseswithcellfusionandmyotubeformationtoamaximumatthefirstmyotubetimepoint.Itslevelthenfallsasthemyotubesdifferentiate.AsimilarmodeofregulationwasfoundwiththemajorConAreceptor(48K)andthemajorWGAreceptor(82–87K).

[学科分类] 生物科学（综合）