Microtubule Patterning during Meiotic Maturation in Mouse Oocytes Is Determined by Cell Cycle-Specific Sorting and Redistribution of γ-Tubulin

[摘要] Thetopographyofmicrotubuleassemblyeventsduringmeioticmaturationofanimaloocytesdemandstightspatialcontrolandtemporalprecision.Tobetterunderstandwhatregulatesthetimingandlocationofmicrotubuleassembly,synchronouslymaturingmouseoocyteswereevaluatedwithrespecttoγ-tubulin,pericentrin,andtotaltubulinpolymerfractionsatspecificstagesofmeioticprogression.γ-Tubulinremainedassociatedwithcytoplasmiccentrosomesthroughdiakinesisofmeiosis-1.Followingchromatincondensationandperinuclearcentrosomeaggregation,γ-tubulinrelocatedtoanuclearlamina-boundedcompartmentinwhichmeiosis-1spindleassemblyoccurred.γ-Tubulinwasstablyassociatedwiththemeioticspindlefromprometaphase-1throughtoanaphase-2,butalsoexhibitedcellcycle-specificrelocalizationtocytoplasmiccentrosomes.Specifically,anaphaseonsetofbothmeiosis-1and-2wascharacterizedbytheconcomitantappearanceofγ-tubulinandmicrotubulenucleationinsubcorticalcentrosomes.Briefpulsesoftaxolappliedatspecificcellcyclestagesenhanceddetectionofγ-tubulincompartmentalization,consistentwithaγ-tubulinlocalization-dependentspatialrestrictionofmicrotubuleassemblyduringmeioticprogression.Inaddition,ataxolpulseduringmeioticresumptionimpairedsubsequentγ-tubulinsorting,resultinginmonopolarspindleformationandcellcyclearrestinmeiosis-1;despitecellcyclearrest,polarbodyextrusionoccurredroughlyonschedule.Therefore,sortingofγ-tubulinisinvolvedinboththetimingoflocationofmeioticspindleassemblyaswellasthecoordinationofkaryokinesisandcytokinesisinmouseoocytes.

[学科分类] 生物科学（综合）

[关键词] Î³-tubulin;centrosome;spindle;nuclear lamina;oocyte;meiosis;nuclear;cytoplasmic maturation