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