Bonifacino J S, Klausner R D, Sandoval I V
Proc Natl Acad Sci U S A. 1985 Feb;82(4):1146-50. doi: 10.1073/pnas.82.4.1146.
A 280-kDa protein (p280) confined to the nucleus of interphase cells becomes associated with the mitotic spindle during cell division. p280 is immunologically related to the microtubule-associated protein MAP1, as shown by cross-reactivity with monoclonal (8D12) and polyclonal antibodies raised against MAP1. However, p280 is distinct from MAP1 as judged by its lower molecular size, proteolytic degradation products, presence in preparations of purified nuclei from which MAP1 is absent, and absence from the cytosol fraction that contains MAP1. Immunofluorescence microscopy of cells in interphase using 8D12 reveals punctate staining of the nucleus, cytoplasmic microtubules, and the microtubule organizing center. Dividing cells display strong staining of the spindle, centrioles, and mid-body. The only exception to this staining pattern is marsupial Pt k2 cells that contain p280 in the nucleus and lack MAP1. These cells exhibit fluorescent staining of the nucleus and the microtubule organizing center when in interphase, of spindle and centrioles in mitosis, and show no staining of cytoplasmic and mid-body microtubules.
一种局限于间期细胞核的280 kDa蛋白质（p280）在细胞分裂期间与有丝分裂纺锤体相关联。如与针对微管相关蛋白MAP1产生的单克隆抗体（8D12）和多克隆抗体的交叉反应所示，p280在免疫学上与微管相关蛋白MAP1相关。然而，根据其较低的分子大小、蛋白水解降解产物、存在于不含MAP1的纯化细胞核制剂中以及不存在于含有MAP1的胞质溶胶部分中判断，p280与MAP1不同。使用8D12对间期细胞进行免疫荧光显微镜检查显示，细胞核、细胞质微管和微管组织中心呈点状染色。分裂细胞的纺锤体、中心粒和中体显示出强烈染色。这种染色模式的唯一例外是有袋类Pt k2细胞，其细胞核中含有p280且缺乏MAP1。这些细胞在间期时细胞核和微管组织中心呈现荧光染色，在有丝分裂时纺锤体和中心粒呈现荧光染色，而细胞质和中体微管无染色。
