The ontogeny of germ plasm during oogenesis in Drosophila☆
[摘要] PrimordialgermcellscanbeinducedatboththeanteriorandventralregionoftheDrosophilaeggbytransplantedposteriorpolarplasm.Twoquestionsarisefromtheseresults:(1)Isfertilizationrequiredforgermplasmtobefunctional,and(2)atwhatstageduringoogenesisdoestheposteriorpolarplasmbecomeestablishedasagerm-celldeterminant?Polarplasmfromunfertilizedeggsandfromoocytesatstage10to14ofDrosophilamelanogasterwasimplantedintotheanteriorregionofcleavageembryos.Someinjectedembryoswereanalyzedattheultrastructurallevelduringblastodermformation.Polarplasmfromunfertilizedeggsandfromoocytesofstages13and14wasfoundtobeintegratedintoseveralanteriorcellsthatresembledmorphologicallynormalpolecells.Theformationofsuchcells,however,couldnotbedetectedinembryosinjectedwithpolarplasmfromoogeneticstages10to12.Experimentallyinducedpolecellsprovedtobecapableofdifferentiatingintofunctionalgermcellswhencycledthroughthegermlineofgeneticallydifferenthostembryos.About5%ofthefliesdevelopingfromtheseembryosproducedprogenythatoriginatedfromtheinducedpolecells.Germ-linemosaicisminthosefliesalsocouldbedetectedhistochemicallyintheirgonads.Nogermcellswererecoveredwithpolarplasmtransplantsfromoogeneticstages10to12.Theresultsshowthatposteriorpolarplasmoftheunfertilizedeggisfunctionalingerm-celldetermination,andthatpriortoeggmaturationthiscytoplasmhasalreadyacquireditsdeterminativeability.Thisisthefirstdemonstrationthatspecificdevelopmentalinformationstoredinthecytoplasmcanbetracedbacktoaparticularregionoftheoocyte.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
