Ectopic formation of primordial germ cells by transplantation of the germ plasm: Direct evidence for germ cell determinant in Xenopus

摘要

Inmanyanimals,thegermlineisspecifiedbyadistinctcytoplasmicstructurecalledgermplasm(GP).GPisnecessaryforprimordialgermcell(PGC)formationinanuranamphibiansincludingemXenopus/em.However,itisunclearwhetherGPisadirectgermcelldeterminantinvertebrates.HerewedemonstratethatGPactsautonomouslyforgermcellformationinemXenopus/em./ppid="sp0045"EGFP-labeledGPfromthevegetalpolewastransplantedintoanimalhemisphereofrecipientembryos.CellscarryingtransplantedGP(T-GP)attheectopicpositionshowedcharacteristicssimilartotheendogenousnormalPGCsinsubcellulardistributionofGPandpresenceofgermplasmspecificmolecules.However,T-GP-carrying-cellsintheectopictissuedidnotmigratetowardsthegenitalridge.T-GP-carryingcellsfromgastrulaortailbudembryosweretransferredintotheendodermofwild-typehosts.Fromthere,theymigratedintothedevelopinggonad.ToclarifywhetherectopicT-GP-carryingcellscanproducefunctionalgermcells,theywereidentifiedbychangingtherecipients,fromthewild-typeemXenopus/emtotransgenicemXenopus/emexpressingDsRed2.AftertransferringT-GPcarryingcellslabeledgeneticallywithDsRed2intowild-typehosts,wecouldfindchimericgonadsinmaturehosts.Furthermore,thespermatozoaandeggsderivedfromT-GP-carryingcellswerefertile.Thus,wehavedemonstratedthatemXenopus/emgermplasmissufficientforgermcelldetermination./p/div