Differential distribution of exosome subunits at the nuclear lamina and in cytoplasmic foci
Differential distribution of exosome subunits at the nuclear lamina and in cytoplasmic foci
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DOI：
10.1091/mbc.e05-08-0805
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发表时间：
2006-03-01
影响因子：
3.3
通讯作者：
Andrulis, ED
中科院分区：
文献类型：
--
作者：
Graham, AC;Kiss, DL;Andrulis, ED
外泌体复合物在RNA加工和周转中起重要作用。尽管对外泌体功能有着重要的机制性认识，但我们仍然缺乏对外泌体复合物生物发生和功能发生的亚细胞区域的基本了解。在这里，我们采用了一组表达表位标记的外泌体亚基的果蝇S2稳定细胞系来研究外泌体复合物组分的亚细胞分布。我们表明，标记的果蝇外泌体亚基纳入复合物，恢复内源性核和细胞质外泌体亚基。免疫定位分析表明，表位标记的和内源性外泌体亚基的子集在离散的亚细胞区室中富集。特别地，dRrp 4、dRrp 42、dRrp 46和dCs 14富集在细胞质灶中。尽管dRrp 4和dRrp 42有时与dCs 14共定位，但这些亚基主要存在于不同的细胞质隔室中。引人注目的是，dRrp 44/dDis 3和dRrp 41/dSki 6与核纤层共定位，并且通常在核周边表现出受限和不对称的分布。总之，这些观察结果表明，单个外泌体亚基在体内具有不同的定位。这些不同的分布模式可能反映了不同的外泌体亚基亚复合物具有相应的专门功能。
The exosome complex plays important roles in RNA processing and turnover. Despite significant mechanistic insight into exosome function, we still lack a basic understanding of the subcellular locales where exosome complex biogenesis and function occurs. Here, we employ a panel of Drosophila S2 stable cell lines expressing epitope-tagged exosome subunits to examine the subcellular distribution of exosome complex components. We show that tagged Drosophila exosome subunits incorporate into complexes that recover endogenous nuclear and cytoplasmic exosome subunits. Immunolocalization analyses demonstrate that subsets of both epitope-tagged and endogenous exosome subunits are enriched in discrete subcellular compartments. In particular, dRrp4, dRrp42, dRrp46, and dCs14 are enriched in cytoplasmic foci. Although dRrp4 and dRrp42 sometimes colocalize with dCs14, these subunits are predominantly found in distinct cytoplasmic compartments. Strikingly, dRrp44/dDis3 and dRrp41/dSki6 colocalize with the nuclear lamina and often exhibit a restricted and asymmetric distribution at the nuclear periphery. Taken together, these observations indicate that individual exosome subunits have distinct localizations in vivo. These different distribution patterns presumably reflect distinct exosome subunit subcomplexes with correspondingly specialized functions.