Nonequivalence of Maternal Centrosomes/Centrioles in Starfish Oocytes: Selective Casting-Off of Reproductive Centrioles into Polar Bodies

Developmental Biology

Setsuko Washitani-Nemoto¹  Koichi H. Kato¹  Yumi Uetake¹  Shin-ichi Nemoto¹ 

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

关键词: centrosome;    centriole;    centrosome reproduction;    centriole duplication;    starfish;    oocyte;    meiosis;    spindle;   

DOI  :  10.1006/dbio.2002.0682

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Itisbelievedthatinmostanimalsonlythepaternalcentrosomeprovidesthedivisionpolesformitosisinzygotes.Thispaternalinheritanceofthecentrosomesdependsontheselectivelossofthematernalcentrosome.Inordertounderstandthemechanismofcentrosomeinheritance,thebehaviorofallmaternalcentrosomes/centrioleswasinvestigatedthroughoutthemeioticandmitoticcyclesbyusingstarfisheggsthathadpolarbody(PB)formationsuppressed.Instarfishoocytes,thecentriolesdonotduplicateduringmeiosisII.Hence,eachcentrosomeofthemeiosisIIspindlehasonlyonecentriole,whereasinmeiosisI,eachhasapairofcentrioles.WhentwopairsofmeiosisIcentrioleswereretainedinthecytoplasmofoocytesbycompletesuppressionofPBextrusion,theyseparatedintofoursinglecentriolesinmeiosisII.However,aftercompletionofthemeioticprocess,onlytwoofthefoursinglecentrioleswerefoundinadditiontothepronucleus.WhenthetwosinglecentriolesofameiosisIIspindlewereretainedintheoocytecytoplasmbysuppressingtheextrusionofthesecondPB,onlyonecentriolewasfoundwiththepronucleusafterthecompletionofthemeioticprocess.WhenthesePB-suppressedeggswereartificiallyactivatedtodrivethemitoticcycles,allthesurvivingsinglecentriolesduplicatedrepeatedlytoformpairsofcentrioles,whichcouldorganizemitoticspindles.Theseresultsindicatethatthematernalcentriolesarenotequivalentintheirintrinsicstabilityandreproductivecapacity.ThecentrosomeswiththereproductivecentriolesareselectivelycastoffintothePBs,resultinginthematureegginheritinganonreproductivecentriole,whichwoulddegradeshortlyafterthecompletionofmeiosis.

【 授权许可】

Unknown