A single subunit, Dis3, is essentially responsible for yeast exosome core activity
A single subunit, Dis3, is essentially responsible for yeast exosome core activity
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DOI：
10.1038/nsmb1184
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发表时间：
2007-01-01
影响因子：
16.8
通讯作者：
Seraphin, Bertrand
中科院分区：
文献类型：
--
作者：
Dziembowski, Andrzej;Lorentzen, Esben;Seraphin, Bertrand
外泌体的保守核心，即主要的真核3' -> 5'外切核酸酶，含有形成类似于磷酸解细菌PNIPs和古细菌外泌体以及Dis 3的环的九个亚基。Dis 3与细菌RNase II（一种水解酶）同源。以前的研究表明，所有亚基都是活性3' -> 5' exoRNA酶。我们在这里表明，Dis 3负责外泌体核心活动。纯化的外泌体核心具有水解、加工和Mg 2+依赖性活性，其特征与重组Dis 3的特征相似。此外，无催化活性的Dis 3突变体在体外没有外泌体核心活性，并且显示出与由外泌体耗尽引起的那些相似的体内RNA降解表型。与此相反，突变Rrp 41，唯一的亚基携带保守的磷酸化位点，出现表型与野生型酵母没有什么不同。我们观察到酵母外泌体环介导与蛋白质伴侣的相互作用，为其基本功能提供了解释。
The conserved core of the exosome, the major eukaryotic 3' -> 5' exonuclease, contains nine subunits that form a ring similar to the phosphorolytic bacterial PNPase and archaeal exosome, as well as Dis3. Dis3 is homologous to bacterial RNase II, a hydrolytic enzyme. Previous studies have suggested that all subunits are active 3' -> 5' exoRNases. We show here that Dis3 is responsible for exosome core activity. The purified exosome core has a hydrolytic, processive and Mg2+-dependent activity with characteristics similar to those of recombinant Dis3. Moreover, a catalytically inactive Dis3 mutant has no exosome core activity in vitro and shows in vivo RNA degradation phenotypes similar to those resulting from exosome depletion. In contrast, mutations in Rrp41, the only subunit carrying a conserved phosphorolytic site, appear phenotypically not different from wild-type yeast. We observed that the yeast exosome ring mediates interactions with protein partners, providing an explanation for its essential function.