DNA synthesis in developing two-cell mouse embryos☆
[摘要] MatedCF1(Carworth)femalemiceweresacrificedat2hrintervalsbetween29and43hrafterhumanchorionicgonadotrophin(HCG)administration.One-andtwo-celleggswereincubatedin[3H]thymidinefor1hr.Labeledtwo-cellembryoswerefirstobservedat31hrandreachedamaximumnumberat35hr.TheSperiodisapproximately6hrinduration.Althoughbothblastomereswerelabeledinmostcases,embryoswithonlyonelabeledblastomereweremorenumerousatlatertimes.Invitrolabelingwascorroboratedbyinjecting[3H]thymidinedirectlyintotheisthmicportionoftheoviduct.Embryosusuallycompletethesecondcleavagedivision18–20hrafteronsetofDNAsynthesis.Thecellcycleatthetwo-cellstageisthuscharacterizedbyaG1ofcloseto1hr,a6hrS,andaG2ofabout12hr.Embryosdevelopinginvitrofrequentlyfailtoprogressbeyondthetwo-cellstage.TheblockisnotduetoabsenceofDNAsynthesissincetheseembryoswerefoundtoincorporate[3H]thymidine.
[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]
