Fertilization Blocks Apoptosis of Starfish Eggs by Inactivation of the MAP Kinase Pathway

Developmental Biology

Kazuyoshi Chiba¹  Kayoko Sasaki¹ 

[1] Department of Biology, Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo, 112-8610, Japan

关键词: starfish;    egg;    apoptosis;    caspase;    MAP kinase;    Mos;    fertilization;    maturation;   

DOI  :  10.1006/dbio.2001.0337

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

FullygrownstarfishoocytesarearrestedatprophaseofmeiosisI.Thehormonalstimulationof1-methyladenine(1-MA)inducesmeiosisreinitiationandgerminalvesiclebreakdown(GVBD).OptimaldevelopmentoccurswhenmaturingoocytesarefertilizedbetweenGVBDandfirstpolarbodyemission.Intheabsenceofsperm,oocytescompletebothmeioticdivisionstoyieldhaploidinterphase-arrestedeggs.Wenowreportthatspontaneousandsynchronousactivationofcaspase-3instarfisheggsoccurs9–12hafter1-MAstimulation.Then,caspase-dependentmembraneblebbingandeggfragmentationoccur,indicatingthatmatureeggsundergoapoptosisifnotfertilized.Activationofcaspase-3andinductionofapoptosisareblockedbothbyaMEKinhibitorandbyemetinetreatmentwhichinhibitsMEKkinase(Mos)synthesis.Conversely,whenrecombinantGST-Mosisinjectedintotheemetine-treatedeggs,apoptosisisinduced.TheseresultsindicatethatpersistentactivationoftheMos/MEK/MAPkinasecascadegivesthedeath-activatingsignalinstarfisheggs.FertilizationinactivatestheMAPkinasepathwayandsuppressesapoptosis,followedbynormaldevelopment.

【 授权许可】

Unknown