Marvin M J, Dahlstrand J, Lendahl U, McKay R D
Laboratory of Molecular Biology, Basic Neurosciences Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
J Cell Sci. 1998 Jul 30;111 ( Pt 14):1951-61. doi: 10.1242/jcs.111.14.1951.
Neuroepithelial and radial glial cells span between the ventricular and the pial surfaces of the neural tube and express two intermediate filaments (IFs), nestin and vimentin, which form a filamentous network throughout the length of the cells. In this report we study the polymerization characteristics of nestin and examine how mutations affect the assembly and localization of the nestin protein in cultured cells and in the developing CNS of transgenic mice. A wild-type rat nestin gene transfected into the IF-free SW13 cell line failed to assemble into a filamentous network but was incorporated into the existing IF network of a subclone expressing vimentin, demonstrating that nestin requires vimentin for proper assembly. In transgenic mice, rat nestin formed a network indistinguishable from that formed by endogenous nestin and vimentin, but a mutant form lacking five amino acids at the carboxy terminus of the rod domain was largely restricted to the pial endfeet. Since nestin mRNA is localized to the pial endfoot region we propose that both transgenes are translated there, but that the wild-type protein is preferentially incorporated into the IF network. These observations provide evidence for hierarchical assembly and a complex organization of the IF network along the ventricular-pial axis in the early CNS.
神经上皮细胞和放射状胶质细胞横跨神经管的室管膜表面和软膜表面，并表达两种中间丝（IFs），即巢蛋白和波形蛋白，它们在细胞全长形成丝状网络。在本报告中，我们研究了巢蛋白的聚合特性，并研究了突变如何影响巢蛋白在培养细胞和转基因小鼠发育中的中枢神经系统中的组装和定位。转染到无中间丝的SW13细胞系中的野生型大鼠巢蛋白基因未能组装成丝状网络，但被整合到表达波形蛋白的亚克隆的现有中间丝网络中，这表明巢蛋白的正确组装需要波形蛋白。在转基因小鼠中，大鼠巢蛋白形成的网络与内源性巢蛋白和波形蛋白形成的网络无法区分，但在杆状结构域羧基末端缺少五个氨基酸的突变形式主要局限于软膜终足。由于巢蛋白mRNA定位于软膜终足区域，我们推测两种转基因都在那里翻译，但野生型蛋白优先整合到中间丝网络中。这些观察结果为早期中枢神经系统中沿室管膜 - 软膜轴的中间丝网络的分级组装和复杂组织提供了证据。
