Mitchison T J, Kirschner M W
J Cell Biol. 1985 Sep;101(3):766-77. doi: 10.1083/jcb.101.3.766.
We have studied the interaction of preformed microtubules (MTs) with the kinetochores of isolated chromosomes. This reaction, which we call MT capture, results in MTs becoming tightly bound to the kinetochore, with their ends capped against depolymerization. These observations, combined with MT dynamic instability, suggest a model for spindle morphogenesis. In addition, ATP appears to mobilize dynamic processes at captured MT ends. We used biotin-labeled MT seeds to follow assembly dynamics at the kinetochore. In the presence of ATP and unlabeled tubulin, labeled MT segments translocate away from the kinetochore by polymerization of subunits at the attached end. We have termed this reaction proximal assembly. Further studies demonstrated that translocation could be uncoupled from MT assembly. We suggest that the kinetochore contains an ATPase activity that walks along the MT lattice toward the plus end. This activity may be responsible for the movement of chromosomes away from the pole in prometaphase.
我们研究了预先形成的微管（MTs）与分离染色体的动粒之间的相互作用。我们将这种反应称为MT捕获，其结果是MTs紧密结合在动粒上，其末端被封闭以防止解聚。这些观察结果，结合MT的动态不稳定性，提示了一种纺锤体形态发生的模型。此外，ATP似乎能促进捕获的MT末端的动态过程。我们使用生物素标记的MT种子来追踪动粒处的组装动态。在ATP和未标记微管蛋白存在的情况下，标记的MT片段通过附着末端亚基的聚合从动粒处移位。我们将这种反应称为近端组装。进一步的研究表明，移位可以与MT组装解偶联。我们认为动粒含有一种沿着MT晶格向正端移动的ATP酶活性。这种活性可能是导致染色体在有丝分裂前期远离纺锤体极移动的原因。
