Mitchison T J, Kirschner M W
J Cell Biol. 1985 Sep;101(3):755-65. doi: 10.1083/jcb.101.3.755.
We have isolated chromosomes from Chinese hamster ovary cells arrested in mitosis with vinblastine and examined the interactions of their kinetochores with purified tubulin in vitro. The kinetochores nucleate microtubule (MT) growth with complex kinetics. After an initial lag phase, MTs are continuously nucleated with both plus and minus ends distally localized. This mixed polarity seems inconsistent with the formation of an ordered, homopolar kinetochore fiber in vivo. As isolated from vinblastine-arrested cells, kinetochores contain no bound tubulin. The kinetochores of chromosomes isolated from colcemid-arrested cells or of chromosomes incubated with tubulin in vitro are brightly stained after anti-tubulin immunofluorescence. This bound tubulin is probably not in the form of MTs. It is localized to the corona region by immunoelectron microscopy, where it may play a role in MT nucleation in vitro.
我们从用长春花碱阻滞在有丝分裂期的中国仓鼠卵巢细胞中分离出染色体，并在体外研究了它们的动粒与纯化微管蛋白的相互作用。动粒以复杂的动力学方式使微管（MT）生长成核。在最初的延迟期之后，微管持续成核，其正端和负端都位于远端。这种混合极性似乎与体内有序的、同极动粒纤维的形成不一致。从长春花碱阻滞的细胞中分离出的动粒不含有结合的微管蛋白。从秋水仙酰胺阻滞的细胞中分离出的染色体的动粒或在体外与微管蛋白一起孵育的染色体的动粒，在抗微管蛋白免疫荧光后被明亮地染色。这种结合的微管蛋白可能不是微管的形式。通过免疫电子显微镜观察，它定位于冠区，在那里它可能在体外微管成核中起作用。
