Differences in the histogenesis and keratin expression of avian extraembryonic ectoderm and endoderm recombined with dermis☆

摘要

Theresponsesofthechorionicectodermandallantoicendoderm(from8-daychickembryos)todermalinductionwerecomparedthroughtissuerecombinantsgraftedontothechorioallantoicmembrane.Thechorionicepitheliumformedtheappropriateepidermiswithafullydevelopedstratumcorneuminresponsetobothspurandscutatescaledermises.Analysisoftheserecombinantepidermaltissuesbysodiumdodecylsulfate-polyacrylamidegelelectrophoresis(SDS-PAGE)demonstratedthattissue-specificexpressionofthealpha(?±)andbeta(?2)keratinpolypeptidesoccurred.Inaddition,indirectimmunofluorescencestudieswithantiserato?±or?2keratinsshowedthatthebetastratum,whichcharacterizestheepidermisofspursandscutatescales,wasformed,andthe?±keratinsweredistributedasinthenormalepidermaltissues.Incontrast,althoughtheallantoicendodermbecamestratifiedinassociationwitheitherspurorscutatescaledermis,astratumcorneumwithabetastratumdidnotdevelop.SDS-PAGEanalysisdemonstratedthatwhilethecharacteristic?2keratinsofscutatescalesandspurwerenotdetected,mostofthe?±keratinsnormallyelaboratedbythesestructureswerepresent,suggestingthatevenwithouthistogenesisofastratumcorneumtheexpressionof?±keratinsofendodermcouldberegulatedinatissue-specificmannerbydermis.Thisstudyalsodemonstratedthattherearedifferencesintheabilitiesofthechorionicandallantoicepitheliatorespondtothesamedermalcues,whichmayreflectearlierrestrictionsintheirdevelopmentalpotentials.