Suelmann R, Sievers N, Fischer R
Laboratorium für Mikrobiologie, Philipps-Universität Marburg and Max-Planck-Institut für terrestrische Mikrobiologie, Germany.
Mol Microbiol. 1997 Aug;25(4):757-69. doi: 10.1046/j.1365-2958.1997.5131873.x.
Nuclear migration and nuclear positioning are fundamental processes in all eukaryotic cells. They are easily monitored during hyphal growth of filamentous fungi. We expressed the green fluorescent protein (GFP) as a fusion protein with the putative nuclear localization domain of the transcriptional activator stuA in nuclei of Aspergillus nidulans and visualized these organelles in living cells. Nuclear staining was observed in interphase nuclei but not during mitosis. Nuclear division, nuclear migration, septum formation and branching were analysed with time-lapse video microscopy during hyphal extension. Hyphae elongated at 0.1-1.2 microm min(-1) and nuclei moved with similar speeds towards the hyphal tip until they had reached a defined position. An individual regulation of nuclear mobility in a given hyphal compartment was observed. Some representative movies are available on the Internet (http://www.blacksci.co.uk/products/journals/molextra.htm). Nuclear positioning was also studied at the molecular level. The ApsA protein, which regulates nuclear migration, was localized at the cytoplasmic membrane in germlings and hyphae by immunofluorescence and GFP tagging. A model of nuclear migration, nuclear positioning and the role of ApsA is presented.
核迁移和核定位是所有真核细胞中的基本过程。在丝状真菌的菌丝生长过程中，它们很容易被监测到。我们将绿色荧光蛋白（GFP）与转录激活因子stuA的假定核定位结构域融合表达，使其在构巢曲霉的细胞核中作为融合蛋白存在，并在活细胞中观察这些细胞器。在间期细胞核中观察到了核染色，但在有丝分裂期间未观察到。在菌丝延伸过程中，通过延时视频显微镜分析了核分裂、核迁移、隔膜形成和分支情况。菌丝以0.1 - 1.2微米/分钟（-1）的速度伸长，细胞核以相似的速度向菌丝尖端移动，直到它们到达一个确定的位置。观察到在给定的菌丝隔室中核迁移存在个体调控。一些代表性的视频可在互联网上获取（http://www.blacksci.co.uk/products/journals/molextra.htm）。还在分子水平上研究了核定位。通过免疫荧光和GFP标记，调节核迁移的ApsA蛋白定位于芽孢和菌丝的细胞质膜上。本文提出了一个核迁移、核定位及ApsA作用的模型。
