Acetylated α-tubulin in microtubules during mouse fertilization and early development

摘要

?±-Tubulininthemicrotubulesofmouseoocytesandembryosisacetylatedinaspecificspatialandtemporalsequence.Intheunfertilizedoocyte,amonoclonalantibodytotheacetylatedformof?±-tubulinisboundpredominantlyatthepolesofthearrestedmetaphasemeioticspindle.Thelabelingintensityofthespindlemicrotubulesisweakerasobservedbyimmunofluorescenceusingoocytesdouble-labeledfortotaltubulinandacetylated?±-tubulin,andasmeasuredbyimmunohigh-voltageelectronmicroscopy(immunoHVEM)withcolloidalgold;cytastersarenotacetylated.Atmeioticanaphase,thespindlebecomeslabeled,andbytelophaseandduringsecondpolarbodyformationonlythemeioticmidbodyisacetylated.Thespermaxonemeretainsitsacetylationafterincorporationthoughtheinterphasemicrotubulesarenotdetected.Firstmitosisfollowsapatternsimilartothatobservedatthesecondmeiosisandduringinterphaseonlythemitoticmidbodiesareacetylated.Aftertreatmentwithcold,colcemid,orgriseofulvin,theremainingstablemicrotubulesareacetylated,butimmunoHVEMobservationssuggestthatthesefibersmightnothavebeenacetylatedpriortomicrotubuledisruption.Taxolstabilizationdoesnotalteracetylationpatterns.Acetylatedmicrotubulesarenotnecessarilyoldmicrotubulessinceacetylatedfibersareobservedat30secaftercoldrecovery.Theseresultsshowthepresenceofacetylatedmicrotubulesduringmeiosisandmitosisanddemonstrateacell-cycle-specificpatternofacetylation,withacetylatedmicrotubulesfoundatthecentrosomesatmetaphase,anincreaseinspindlelabelingatanaphase,andtheselectivedeacetylationofallbutmidbodymicrotubulesattelophase.