Uemura Tomohiro, Suda Yasuyuki, Ueda Takashi, Nakano Akihiko
Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033 Japan.
Plant Cell Physiol. 2014 Apr;55(4):694-703. doi: 10.1093/pcp/pcu010. Epub 2014 Jan 18.
The trans-Golgi network (TGN) is an important organelle for protein transport at the post-Golgi network, which functions as a sorting station that directs cargo proteins to a variety of destinations including post-Golgi compartments and the extracellular space. However, the functions and dynamics of the TGN in plant cells have not been well understood yet. To elucidate the dynamics of the plant TGN, we established transgenic plants expressing green fluorescent protein (GFP)-SYP43, the ortholog of Tlg2/syntaxin16, which is localized to the TGN in yeast and mammalian cells, under the control of the native promoter as a TGN marker. Observation by confocal laser scanning microscopy and super-resolution confocal live imaging microscopy revealed two types of TGN in Arabidopsis root: the GA-TGNs (Golgi-associated TGNs), located on the trans-side of the Golgi apparatus, and the GI-TGNs (Golgi-released independent TGNs), located away from the Golgi apparatus and behaving independently. The GI-TGNs is derived from a population of GA-TGNs by segregation, although the core of the GA-TGN remains even after the generation of the GI-TGN. We further found that the abundance of the GI-TGNs differs between observed tissues. Our results indicate that the dynamic features of the TGN in plant cells differ from those of animal and yeast cells.
反式高尔基体网络（TGN）是高尔基体后网络中蛋白质运输的重要细胞器，它作为一个分拣站，将货物蛋白导向包括高尔基体后区室和细胞外空间在内的各种目的地。然而，植物细胞中TGN的功能和动态变化尚未得到很好的理解。为了阐明植物TGN的动态变化，我们构建了在天然启动子控制下表达绿色荧光蛋白（GFP）-SYP43（Tlg2/ syntaxin16的直系同源物，在酵母和哺乳动物细胞中定位于TGN）的转基因植物，作为TGN标记。通过共聚焦激光扫描显微镜和超分辨率共聚焦实时成像显微镜观察发现，拟南芥根中有两种类型的TGN：GA-TGN（高尔基体相关TGN），位于高尔基体的反面；GI-TGN（高尔基体释放的独立TGN），远离高尔基体且独立存在。GI-TGN是由GA-TGN群体通过分离产生的，尽管在GI-TGN产生后GA-TGN的核心仍然存在。我们进一步发现，观察到的不同组织中GI-TGN的丰度有所不同。我们的结果表明，植物细胞中TGN的动态特征与动物和酵母细胞不同。
