Dynamic activity of the filopodia of sea urchin embryonic cells and their role in directed migration of the primary mesenchyme in vitro☆

摘要

PrimarymesenchymecellsusedinthisstudywereisolatedfromLytechinuspictusmesenchymeblastulaebytheirabilitytopreferentiallyadheretothesurfaceofatissueculturedishinthepresenceofserum.Onceisolated,primarymesenchymecellswerefoundtoformthin,elongated,activefilopodiawhichcloselyresemblethefilopodiaseeninvivo.Thefilopodiaformedinvitrocanmoveasstiffenedbristles,bendgraduallyorverysharply,orbeslowlywithdrawn.TheintegrityofthefilopodiaisnotaffectedbynocodazolebutistotallydisruptedbycytochalasinD.Filopodiaexhibitseveralapparentfunctionsinvitro:asorganellesinvolvedincontactingtheexternalenvironment,asanchoringappendagesthatholdthecellbodiesinplace,andasintercellularconnectivesthatcanjoincellbodies.Thefilopodiaofprimarymesenchymecellsappeartohavesimilarroleswithintheembryo.Thefunctionofthefilopodiahasbeenexploredbywatchingthebehaviorofisolatedprimarymesenchymecellsincloseproximitytodepositsofextracellularmaterial(ECM)preparedfrommesenchymeblastulae.WhenthefilopodiumfromamesenchymecellmakescontactwiththenearbyECM,aresponseisinitiatedwhichcausesthecellbodytomoveinadirectedmannertowardtheECMdeposit.Theuseofthistypeofresponseasamodelsystemforthestudyofthemigrationofprimarymesenchymecellswithintheembryoisconsidered.