6-DMAP诱导PM胚胎形成过程中核纤层蛋白B的动力学变化

我们的前期研究发现:被微管抑制剂nocodazole抑制在第一次有丝分裂中期的小鼠受精卵在加入6-DMAP处理后核膜重新出现,并且父、母本的基因组未发生融合,分别形成了类似雌、雄原核的两个细胞核,它们共存于卵细胞质中,我们把这种特殊的胚胎称之为PM胚胎(post-mitoticembryo)。本研究表明:在去除抑制剂3h后未能形成核膜的胚胎进一步卵裂,而形成核膜的PM胚胎培养24h未见进一步发育。此外,我们采用免疫荧光染色观察PM胚胎核膜重现过程中核纤层蛋白B的动力学变化,结果显示:在加入6-DMAP后核纤层蛋白B在染色体周围逐渐聚集,约3h后核膜完全形成,此时核纤层蛋白B在染色体周围的聚集达到最高峰。文中还对6-DMAP诱导核膜形成的机制进行了探讨。

Dynamic Characteristics of Lamin B during the Formation of PM-embryos Induced by 6-DMAP

Our previous researches indicated that nuclear envelope reocurred after adding 6-DMAP when mouse embryos were inhibited by nocodazole in the metaphase of the first mitosis. The paternal and maternal genomes reconstructed male and female pronuclear-like nuclei respectively, rather than fusing into one single karyocyte. These embryos were designated as post-mitotic embryos (PM-embryos), in which two special nuclei exist in zygotic cytoplasm. This study indicated that after being removed the inhibitor (6-DMAP and nocodazole), the embryos without nuclear envelope reoccurrence could further develop to cleavage, while the PM-embryos could not after being cultured for 24 hours. Furthermore, we investigated the dynamic characteristics of lamin B by immunofluorescence during the nuclear envelope reconstruction of PM-embryos. The result showed that lamin B recruited to the chromosome gradually after 6-DMAP was added into the culture solution. Integrated Nuclear envelope formed about 3 hours later when the recruitment of lamin B reached the maximum level. The mechanism of the formation of the nuclear envelope induced by 6-DMAP is also discussed in this article.