Theisen Ulrike, Straube Anne, Steinberg Gero
Max-Planck-Institut für terrestrische Mikrobiologie, D-35043 Marburg, Germany.
Mol Biol Cell. 2008 Mar;19(3):1230-40. doi: 10.1091/mbc.e07-02-0130. Epub 2008 Jan 2.
Mitosis in animals starts with the disassembly of the nuclear pore complexes and the breakdown of the nuclear envelope. In contrast to many fungi, the corn smut fungus Ustilago maydis also removes the nuclear envelope. Here, we report on the dynamic behavior of the nucleoporins Nup214, Pom152, Nup133, and Nup107 in this "open" fungal mitosis. In prophase, the nuclear pore complexes disassembled and Nup214 and Pom152 dispersed in the cytoplasm and in the endoplasmic reticulum, respectively. Nup107 and Nup133 initially spread throughout the cytoplasm, but in metaphase and early anaphase occurred on the chromosomes. In anaphase, the Nup107-subcomplex redistributed to the edge of the chromosome masses, where the new envelope was reconstituted. Subsequently, Nup214 and Pom152 are recruited to the nuclear pores and protein import starts. Recruitment of nucleoporins and protein import reached a steady state in G2 phase. Formation of the nuclear envelope and assembly of nuclear pores occurred in the absence of microtubules or F-actin, but not if both were disrupted. Thus, the basic principles of nuclear pore complex dynamics seem to be conserved in organisms displaying open mitosis.
动物细胞的有丝分裂始于核孔复合体的解体和核膜的破裂。与许多真菌不同，玉米黑粉菌（Ustilago maydis）在有丝分裂时也会去除核膜。在此，我们报道了核孔蛋白Nup214、Pom152、Nup133和Nup107在这种“开放式”真菌有丝分裂中的动态行为。在前期，核孔复合体解体，Nup214和Pom152分别分散到细胞质和内质网中。Nup107和Nup133最初散布于整个细胞质中，但在中期和早后期出现在染色体上。在后期，Nup107亚复合体重新分布到染色体团块的边缘，新的核膜在那里重新形成。随后，Nup214和Pom152被招募到核孔处，蛋白质导入开始。核孔蛋白的招募和蛋白质导入在G2期达到稳定状态。核膜的形成和核孔的组装在没有微管或F-肌动蛋白的情况下发生，但如果两者都被破坏则不会发生。因此，在进行开放式有丝分裂的生物体中，核孔复合体动态变化的基本原理似乎是保守的。
