Transition of DNA polymerase-α and endoplasmic reticulum during gastrulation of the sea urchin☆
[摘要] ChangesintheactivityofDNApolymerase-αandinsubcellulardistributionwerestudiedduringgastrulationoftheseaurchin,Hemicentrotuspulcherrimus.AlthoughtheactivityofDNApolymerase-αforeachembryowasconstantuptotheblastulastageasreportedpreviously,theenzymeactivityincreasedduringgastrulationbyabouttwofoldpriortoanincreaseinitsDNAcontent.Thereaftertheenzymeactivityremainedconstantatahighleveluntiltheearlypluteusstage.Duringgastrulation,anincreaseinthefractionofDNApolymerase-αwasassociatedwiththeroughendoplasmicreticulum.Duringtheperiodbetweenthegastrulaandpluteusstages,thecytoplasmicDNApolymerase-αactivitydecreasedgraduallywithaconcomitantincreaseofactivityinthenucleusfraction.ThetimingofthisincreaseinthenucleuscoincidedwiththeincreaseofDNAcontentperembryo.TheseresultssuggestthatDNApolymerase-αaccumulatesontheroughendoplasmicreticulumduringgastrulationandthentranslocatestothenucleusforDNAsynthesisasseenbeforetheblastulastage.DNApolymerase-αobtainedfromgastrulanucleididnotassociatewiththeendoplasmicreticulumfromgastrulae.DNApolymerase-αobtainedfromthegastrulaendoplasmicreticulummembranesbecameboundtothesalt-washedmembranesfromgastrulaebutnottothosefromunfertilizedeggs.Likewise,DNApolymerase-αfromtheroughendoplasmicreticulumofunfertilizedeggsbecameattachedtosalt-washedmembranesfromunfertilizedeggs,butnottothosefromgastrulae.ThissuggeststhatDNApolymerase-αissynthesizedanew,andatransitionofbothDNApolymerase-αandendoplasmicreticulumoccursatthegastrulastage.
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[效力级别] [学科分类] 生物科学（综合）
[关键词] [时效性]
