Distribution of fibronectin in the early phase of avian cephalic neural crest cell migration☆
[摘要] Immunofluorescenceandimmunoperoxidaselabelingforfibronectinwasusedtostudytheearlyeventsofcephalicneuralcrestcellmigrationinavianembryos.Priortocrestcellappearance,fibronectinwasassociatedwiththebasementmembranesofalltissues.Theloosemesenchymalcellswerealsosurroundedbythisglycoprotein.Thecrestcellindividualizationphaseincludedatransientroundingupandarapidincreaseincellnumberinaverylimitedspace.Whereastheneuraltubebasementmembranewasnotformeddorsallyatthesiteofemergenceofcrestcells,itwaspartiallyfusedlaterallywiththeectodermbasementmembraneapparentlypreventingimmediatecrestcellemigration.Furtherincreaseincellnumberoccurredconcomitantlywiththeirpenetrationbetweenthetwodevelopingbasementmembranesoftheneuraltubeandtheectoderm.Thelocalizationofmigratingcrestcellsisapparentlygreatlyinfluencedbylocalinteractionsbetweentheectodermandtheneuraltube,whosemorphogenesisdiffersconsiderablyateachaxiallevel:atthemesencephalic-rhombencephaliclevels,crestcellsrapidlyreachedacell-freespacethatwasmostlydevoidoffibronectin.Furthermigrationoccurredlaterallyinthatspacewhilepioneercrestcellsbecamesurroundedbyfibronectinintheirenvironment.Crestcellsprogressedasaconfluentmulticellularlayerwithanapparentvelocityof70μm/hr.Attheprosencephalicandmedianrhombencephaliclevels,crestcellsaccumulatedbetweenthefibronectin-richbasementmembranesoftheectodermandtheneuraltube.Pioneercrestcellswerearrestedatthesiteofattachmentoftheectodermandtheneuraltubebasementmembranes(i.e.,opticvesiclesandoticplacodes).Crestcellsresumedtheirmigrationwhenmorespacebecameavailableduringtheconstrictionoftheopticvesiclesandtheinvaginationoftheoticplacodes.
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[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
