Dentler W L, Granett S, Rosenbaum J L
J Cell Biol. 1975 Apr;65(1):237-41. doi: 10.1083/jcb.65.1.237.
Microtubules isolated from brain extracts by in vitro assembly (1, 19, 23) are composed principally of two tubulins and two high molecular weight proteins (microtubule-associated proteins [MAPS] 1 and 2) (2,5,7,20). Recently, it was demonstrated that in vitro-assembled brain microtubules (neurotubules) are coated with filaments (5, 7) which are similar to the filaments attached to neurotubules in situ (4, 15, 21, 24, 25), and it was suggested that the filaments are composed of the higher molecular weight MAPs (5, 7, 12). In this study, microtubules were assembled in the presence and absence of the MAPs, and thin sections of the microtubules were examined by electron microscopy. The results show that the filaments only occur on microtubules assembled in the presence of the MAPs and it is therefore concluded that the filaments are composed of the high molecular weight MAP's.
通过体外组装从脑提取物中分离出的微管（1, 19, 23）主要由两种微管蛋白和两种高分子量蛋白质（微管相关蛋白[MAPS] 1和2）组成（2,5,7,20）。最近，已证明体外组装的脑微管（神经微管）被细丝覆盖（5, 7），这些细丝类似于原位附着在神经微管上的细丝（4, 15, 21, 24, 25），并且有人提出这些细丝由较高分子量的MAPs组成（5, 7, 12）。在本研究中，在有和没有MAPs的情况下组装微管，并通过电子显微镜检查微管的薄片。结果表明，细丝仅出现在有MAPs存在时组装的微管上，因此得出结论，细丝由高分子量的MAPs组成。
