Potential of isolated mouse inner cell masses to form trophectoderm derivatives in vivo☆

[摘要] Recentinvitroexperimentsonimmunosurgicallyisolatedmouseinnercellmasses(ICMs)havesuggestedthatsomeICMcellsmayretainthepotentialtoformtrophectodermafterinitialblastocystformation.Theseexperimentsreliedalmostsolelyoninvitromorphologyforidentificationoftrophectodermderivativesandprovidednoproofthattheputativetrophectodermcellswerecapableoffunctioninginutero.WepresentclearinvivoevidencethatatleastsomecellsinICMsisolatedfromearlyblastocystsdoretainthepotentialtoformpostimplantationtrophectodermderivatives.EarlyICMsoccasionallycontributedtotrophoblastfractionsinICM/morulaaggregationchimeras.Morestrikingly,whenaggregatedwitheachother,theseICMswerecapableofimplantingintheuterus,apropertyoftrophectodermcellsalone.Indeed,someaggregatesreconstitutedcompleteeggcylinders.However,ICMsisolatedfromlaterblastocystsrarelyproducedinvivotrophoblast,anditappearsthattheabilitytoformtrophectodermislostaroundthe16–19cellICMstage.Theseresultsarediscussedinrelationtochangingpatternsofgeneactivityinearlydevelopment.

[学科分类] 生物科学（综合）