The Ability to Develop an Activity That Transfers Histones onto Sperm Chromatin Is Acquired with Meiotic Competence during Oocyte Growth

Developmental Biology

Hugh J. Clarke¹  David W. McLay¹  John Carroll¹ 

[1] Department of Biology, McGill University, Montreal, Canada

关键词: sperm;    chromatin;    histones;    oocyte growth;    meiotic competence;    calcium;   

DOI  :  10.1006/dbio.2001.0499

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Followingfertilization,theoocyteremodelsthespermchromatinintothemalepronucleus.Asacomponentofthisprocess,duringmeioticmaturation,oocytesdevelopanactivitythattransfershistonesontospermDNA.Tofurthercharacterizethisactivity,wetestedwhetheroocytesatdifferentstagesofgrowthcould,uponentryintometaphaseofmaturation,transferhistonesontospermDNA,asjudgedbychromatinmorphologyandimmunocytochemistry.Meioticallycompetentgrowingoocytes,whichspontaneouslyentermetaphaseuponculture,tranferredhistonesontospermchromatin,whereasincompetentoocytesdidnot,evenwhentreatedwithokadaicacidtoinducegerminalvesiclebreakdown(GVBD)andchromosomecondensation.WhenincompetentoocyteswerecultureduntiltheyacquiredtheabilitytoundergoGVBD,onlyasmallproportionalsodevelopedhistone-transferactivityduringmaturation.However,thisproportionsignificantlyincreasedwhentheoocyteswereculturedasgranulosa–oocytecomplexes.Thefailureofhistone-transferactivitytodevelopinincompetentoocytestreatedwithokadaicacidwasnotlinkedtolowH1kinaseactivitynorrescuedbyinjectedhistones.Becausecompetent,butnotincompetent,oocytesproducenaturalcalciumoscillations,incompetentoocyteswereexposedtoSrCl2.One-thirdoftreatedoocytesproducedatleastoneCa2+oscillationand,followinginsemination,thesameproportiontransferredhistonesontospermDNA.HistonetransferdidnotoccurinoocytespretreatedwiththeCa2+chelator,BAPTA-AM.Theseresultsindicatethattheabilitytodevelophistone-transferactivityisacquiredbygrowingoocytesnearthetimeofmeioticcompetence,thatitisseparablefromthisevent,andthatitmayberegulatedthroughaCa2+-dependentprocess.

【 授权许可】

Unknown