Sugimoto M, Tan S S, Takagi N
Division of Bioscience, Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Japan.
Int J Dev Biol. 2000 Feb;44(2):177-82.
Using H253 mouse stock harboring X-linked HMG-lacZ transgene, we examined X chromosome inactivation patterns in sectioned early female embryos. X-gal staining patterns were generally consistent with the paternal X inactivation in the trophectoderm and the primitive endoderm cell lineages and random inactivation in the epiblast lineages. The occurrence of embryonic visceral endoderm cells apparently at variance with the paternal X chromosome inactivation in 7.5 dpc embryos was explained by the replacement of visceral endoderm cells with cells of epiblast origin. The frequency of cells negative for X-gal staining in 4.5-5.5 dpc XmXp* embryos fluctuated considerably especially in the extraembryonic ectoderm and the primitive endoderm, whereas it was less variable in the embryonic ectoderm. We could not, however, determine whether it is a normal phenomenon revealed for the first time by the use of HMG-lacZ transgene or an abnormality caused by the multicopy transgene.
利用携带X连锁HMG - lacZ转基因的H253小鼠品系，我们检查了早期雌性胚胎切片中的X染色体失活模式。X - gal染色模式通常与滋养外胚层和原始内胚层细胞谱系中的父本X染色体失活以及上胚层细胞谱系中的随机失活一致。在7.5天胚龄胚胎中出现的明显与父本X染色体失活不一致的胚胎脏内胚层细胞，可通过用上胚层来源的细胞替代脏内胚层细胞来解释。在4.5 - 5.5天胚龄的XmXp*胚胎中，X - gal染色阴性的细胞频率波动很大，尤其是在胚外外胚层和原始内胚层中，而在胚胎外胚层中变化较小。然而，我们无法确定这是首次使用HMG - lacZ转基因揭示的正常现象还是由多拷贝转基因引起的异常现象。
