PDF(Pubmed)
Abstract：
Connections between the nucleus and the cytoskeleton are important for positioning and division of the nucleus. In most eukaryotes, the linker of nucleoskeleton and cytoskeleton (LINC) complex spans the outer and inner nuclear membranes and connects the nucleus to the cytoskeleton. In opisthokonts, it is composed of Klarsicht, ANC-1 and Syne homology (KASH) domain proteins and Sad1 and UNC-84 (SUN) domain proteins. Given that the nucleus is positioned at the posterior pole of Toxoplasma gondii, we speculated that apicomplexan parasites must have a similar mechanism that integrates the nucleus and the cytoskeleton. Here, we identified three UNC family proteins in the genome of the apicomplexan parasite T. gondii. Whereas the UNC-50 protein TgUNC1 localised to the Golgi and appeared to be not essential for the parasite, the SUN domain protein TgSLP2 showed a diffuse pattern throughout the parasite. The second SUN domain protein, TgSLP1, was expressed in a cell cycle-dependent manner and was localised close to the mitotic spindle and, more detailed, at the kinetochore. We demonstrate that conditional knockout of TgSLP1 leads to failure of nuclear division and loss of centrocone integrity.
摘要：
细胞核和细胞骨架之间的连接对于细胞核的定位和分裂是重要的。在大多数真核生物中，LINC复合物(核骨架和细胞骨架的接头)跨越核外膜和核内膜,并将细胞核连接到细胞骨架。在opisthokonts，它由Klarsicht组成,ANC-1和Syne同源性(KASH)结构域蛋白和Sad1和UNC-84(SUN)结构域蛋白。鉴于细胞核位于弓形虫的后极，我们推测顶丛寄生虫必须具有整合细胞核和细胞骨架的类似机制。这里,我们在尖丛寄生虫弓形虫基因组中鉴定出三个UNC家族蛋白。虽然UNC-50蛋白TgUNC1位于高尔基体，似乎对寄生虫不是必需的，SUN结构域蛋白TgSLP2在整个寄生虫中显示出扩散模式。第二个SUN结构域蛋白，TgSLP1以细胞周期依赖性方式表达，并位于有丝分裂纺锤体附近，更详细,在动管。我们证明TgSLP1的条件性敲除会导致核分裂失败和中心酮完整性丧失。
