Dai Yunping, Wang Lili, Wang Haiping, Liu Ying, Li Ning, Lyu Qifeng, Keefe David L, Albertini David F, Liu Lin
State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing.
Reproduction. 2006 Jun;131(6):1051-61. doi: 10.1530/rep.1.01058.
Cloning mammalians by somatic cell nuclear transfer (SCNT) remains inefficient. A majority of clones produced by SCNT fail to develop properly and of those which do survive, some exhibit early aging, premature death, tumors, and other pathologies associated with aneuploidy. Alterations of centrosomes are linked to aberrant cell cycle progression, aneuploidy, and tumorigenesis in many cell types. It remains to be determined how centrosomes are remodeled in cloned bovine embryos. We show that abnormalities in either distribution and/or number of centrosomes were evident in approximately 50% of reconstructed embryos following SCNT. Moreover, centrosome abnormalities and failed 'pronuclear' migration which manifested during the first cell cycle coincided with errors in spindle morphogenesis, chromosome alignment, and cytokinesis. By contrast, nuclear mitotic apparatus protein (NuMA) exhibited normal expression patterns at metaphase spindle poles and in 'pronucleus' during interphase. The defects in centrosome remodeling and 'pronuclear' migration could lead to chromosome instability and developmental failures associated with embryo production by SCNT. Addressing these fundamental problems may enhance production of normal clones.
通过体细胞核移植（SCNT）克隆哺乳动物的效率仍然很低。大多数通过SCNT产生的克隆无法正常发育，而在那些存活下来的克隆中，有些表现出早衰、过早死亡、肿瘤以及其他与非整倍体相关的病理状况。在许多细胞类型中，中心体的改变与异常的细胞周期进程、非整倍体和肿瘤发生有关。克隆牛胚胎中的中心体是如何重塑的仍有待确定。我们发现，在SCNT后的重建胚胎中，约50%的胚胎中心体的分布和/或数量存在明显异常。此外，在第一个细胞周期中出现的中心体异常和原核迁移失败与纺锤体形态发生、染色体排列和胞质分裂错误同时发生。相比之下，核有丝分裂器蛋白（NuMA）在中期纺锤体极和间期原核中表现出正常的表达模式。中心体重塑和原核迁移的缺陷可能导致染色体不稳定以及与SCNT胚胎生产相关的发育失败。解决这些基本问题可能会提高正常克隆的产量。
