Modulation of fertilization by the vitellus after interaction with peptides released by hamster sperm-zona pellucida contact

[摘要] Twotothreeminutesafterhamsterspermmakecontactwithandadheretothesurfaceofhomologouszonaepellucidaeinvitro,thefirstofseveralsetsofpeptides(S1peptides)isreleasedintothesupernatant.Thisreleaseoccurswhetherthezonaehaveorhavenotbeenmechanicallyseparatedfromthevitellus(cellularpartoftheegg).PresenceoftheS1peptidesisdetectedbymeansofasperm-eggassay,theprematurebindingassay.Thisassayisbasedontheabilityofanaliquotofthemedium,inwhichspermareinteractingwiththezonasurface,toinduceearlybinding,uponadditionofthealiquottoaseconddropofinteractinggametes.Todetermineifthevitellusaffectedthe2-minS1peptidestheultrafiltratesofthesupernatantscontainingthem,releasedthroughsperm-eggandsperm-zonainteractions,werefractionatedonBiogelP-6andtheirelutionprofileswerecomparedusingtheprematurebindingassay.Thesperm-eggultrafiltrateswereresolvedintotwomaindomainsofactivity,whilethoseofthesperm-zonaformedthree.Theultrafiltratescollected2minaftertheinteractionofspermwitheggsorwithisolatedzonaewerecomparedfortheirabilitiestoinhibitthepenetrationofthezonapellucida,apreviouslydemonstratedcapacityofthe2-minsperm-eggS1peptides.Theultrafiltratecontainingthesperm-zonapeptides,exceptataverylowlevel,failedtoinhibitpenetrationsignificantly.However,whenthesperm-zonaultrafiltratewaspreincubatedwitheggsthentheresultingsupernatantinhibitedpenetrationinadose-relatedmanner,andthethree-domainelutionprofile,characteristicofthesperm-zonaultrafiltrate,wasconvertedtotheegg-liketwo-domainprofile.Takentogetherthesedatasuggestthatthe2-minS1peptidesconsistofseveralsubpopulations,atleastoneofwhichinteractswiththevitellus.Theresultingsolutionthenacquirestheabilitytoinhibitpenetrationoftheeggbythesperminadose-relatedmanner.Takentogetherthesedataindicatethatbyinteractingwithatleastoneofthecomponentsofthe2-minpeptides,thevitellusisinvolvedinregulatingsperm-zonainteractions.

[学科分类] 生物科学（综合）