Proteomic analysis of the Arabidopsis nucleolus suggests novel nucleolar functions
Proteomic analysis of the Arabidopsis nucleolus suggests novel nucleolar functions
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DOI：
10.1091/mbc.e04-09-0791
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发表时间：
2005-01-01
影响因子：
3.3
通讯作者：
Shaw, PJ
中科院分区：
文献类型：
--
作者：
Pendle, AF;Clark, GP;Shaw, PJ
真核细胞核仁参与核糖体生物合成以及广泛的其他 RNA 代谢和细胞功能。核仁功能分析的一个重要步骤是确定该核区室的蛋白质补体。在这里，我们描述了植物（拟南芥）核仁的首次蛋白质组分析，其中我们鉴定了 217 种蛋白质。这使得可以直接比较两个差异很大的物种（人类和拟南芥）之间重要核结构的蛋白质组。通过比较，确定了许多常见蛋白质、植物特异性蛋白质、两个蛋白质组中发现的功能未知的蛋白质，以及植物中为核仁但人类中为非核仁的蛋白质。 72 种蛋白质表达为 GFP 融合体，其中 87% 显示核仁或核仁相关定位。在一个惊人且出乎意料的发现中，我们发现了参与 mRNA 输出和无义介导的衰变 (NMD)/mRNA 监视的剪接后外显子连接复合物 (EJC) 的六个组件。 GFP 融合蛋白定位证实了这种关联。这些结果提出了这样一种可能性：在植物中，核仁可能在 mRNA 输出或监视中具有额外的功能。
The eukaryotic nucleolus is involved in ribosome biogenesis and a wide range of other RNA metabolism and cellular functions. An important step in the functional analysis of the nucleolus is to determine the complement of proteins of this nuclear compartment. Here, we describe the first proteomic analysis of plant (Arabidopsis thaliana) nucleoli, in which we have identified 217 proteins. This allows a direct comparison of the proteomes of an important nuclear structure between two widely divergent species: human and Arabidopsis. The comparison identified many common proteins, plant-specific proteins, proteins of unknown function found in both proteomes, and proteins that were nucleolar in plants but nonnucleolar in human. Seventy-two proteins were expressed as GFP fusions and 87% showed nucleolar or nucleolar-associated localization. In a striking and unexpected finding, we have identified six components of the postsplicing exon-junction complex (EJC) involved in mRNA export and nonsense-mediated decay (NMD)/mRNA surveillance. This association was confirmed by GFP-fusion protein localization. These results raise the possibility that in plants, nucleoli may have additional functions in mRNA export or surveillance.