Variation of DNA polymerase activities of rat giant trophoblast cells in mid-gestation☆
[摘要] TheactivitiesoftheDNApolymerasesα,β,andγweredeterminedinratgianttrophoblastcellsduringmid-gestation.TrophoblastsatthisperiodoftimehaveceasedtodividebutcontinuetocarryoutDNAendoreduplicationresultinginpolyploidy.DNApolymerase-αactivityinextractswasfoundtodropsharplyfromahighlevelatDay11to110ofthatlevelatDay12andtocontinueataconstantlevelthereafter.Asimilarpatternofactivitywasobservedforpolymerase-γ,however,inthisecasethedroprepresented50%oftheactivityat11days.Polymerase-βshowednosignificantchangeinactivityduringthisperiodofdevelopment.Endoreduplication(polyploidy)continuedduringthisperiodasmeasuredbyalinearincreaseinchromosomalDNAcontent.Thesharpdropinα-polymeraseactivityfromDay11toDay12appearstoresultfromthelossofaprotein(s)whichspecificallystimulate(s)α-polymerase.
[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]
