Tubulin:tyrosine ligase in oocytes and embryos of Xenopus laevis☆
[摘要] Tubulin:tyrosineligase(TTL),whichcatalyzesthepost-translationaladditionoftyrosinetotheαchainoftubulin,existsinawidevarietyofembryonicandadultvertebratetissues.Inthepresentstudy,wereportthatTTLexistsinamphibianoocytesatatimewhentubulinisapoorsubstratefortyrosination,andwhen,inimmatureoocytes,tubulinisnotpolymerizable.LigaseactivitydetectedatseveralstagesofoogenesisandembryogenesisinXenopusiscompatiblewithmammalianbraintubulininthetyrosinationreaction.Within3–5hrafterfertilization,[3H]tyrosineincorporated/μgendogenoustubulinincreasesapproximately3.5-foldoverthatinextractspreparedfromthelargestoocytesobtained.ThisincreasecannotbeaccountedforbyincreasinglevelsofTTL.Ligaseactivityremainsfairlyconstantthroughoutoogenesisandearlyembryogensisandrisessignificantly(2-fold)only35–50hrafterfertilization.Thelateriseinembryonicligaseactivityisnotaccompaniedbyachangeinapparentkmfortubulin.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
