The mechanical basis of morphogenesis: I. Epithelial folding and invagination☆

[摘要] Wepresentamechanicalmodelforthemorphogeneticfoldingofembryonicepitheliabasedonhypothesizedmechanicalpropertiesofthecellularcytoskeleton.Inourmodelweconsiderasimplecuboidalepitheliumwhosecellsarejoinedattheirapicesbycircumferentialjunctions;tothesejunctionsareattachedcircumferentialarraysofmicrofilamentbundlesassembledintoa“pursestring”aroundthecellapex.Weassumethatthispursestringhasthefollowingproperty:ifitscircumferenceisincreasedbeyondacertainthreshold,anactivecontractionisinitiatedwhich“drawsthepurse-string”andreducestheapicalcircumferenceofthecelltoanew,shorter,restinglength.Theremainderofthecellismodeledasavisoelasticbodyofconstantvolume.Clearlycontractioninonecellcouldstretchtheapicalcircumferencesofneighboringcellsand,ifthethresholdisexceeded,causethem“tofire”andcontract.Theobjectiveofthispaperistodemonstratethatourmodel,basedonthelocalbehaviorofindividualcells,generatesapropagatingcontractionwavewhichissufficienttoexplainthegloballycoherentmorphogeneticinfoldingofawidevarietyofembryonicepithelia.Representativecomputersimulations,basedonthemodel,arepresentedfortheinitialgastrulationmovementsofechinoderms,neuraltubeformationinurodeleamphibians,andventralfurrowformationinDrosophila.

[学科分类] 生物科学（综合）