Compositionally and functionally distinct editosomes in Trypanosoma brucei
Compositionally and functionally distinct editosomes in Trypanosoma brucei
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DOI：
10.1261/rna.45506
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发表时间：
2006-06-01
期刊：
影响因子：
4.5
通讯作者：
Stuart, Kenneth D.
中科院分区：
文献类型：
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作者：
Panigrahi, Aswini K.;Ernst, Nancy Lewis;Stuart, Kenneth D.
布氏锥虫线粒体中的尿苷酸插入/缺失RNA编辑由一种类似于20 S编辑体的多蛋白复合物催化。通过三种相关的标记的RNA酶III蛋白KREN 1（KREPB 1/TbMP 90）、KREPB 2（TbMP 67）和KREN 2（KREPB 3/TbMP 61）纯化的编辑体具有非常相似但不相同的蛋白质组成，并且在每个相应的复合物中仅鉴定出这三种RNA酶III蛋白的标记成员。在这些复合物中还鉴定了三种新的编辑体蛋白。每个标记的复合物在体外催化预切割插入和缺失编辑。然而，KREN 1复合物在体外切割缺失但不切割插入编辑位点，相反，KREN 2复合物切割插入但不切割缺失编辑位点。这些特定的核酸酶活性被废除的推定的RNase III催化结构域的相应蛋白质的突变。因此，编辑体在组成上似乎是异质的，其中KREN 1复合物催化缺失位点的切割，KREN 2复合物切割插入位点，而两者都可以催化编辑的U添加、U去除和连接步骤。
Uridylate insertion/deletion RNA editing in Trypanosoma brucei mitochondria is catalyzed by a multiprotein complex, the similar to 20S editosome. Editosomes purified via three related tagged RNase III proteins, KREN1 (KREPB1/TbMP90), KREPB2 (TbMP67), and KREN2 (KREPB3/TbMP61), had very similar but nonidentical protein compositions, and only the tagged member of these three RNase III proteins was identified in each respective complex. Three new editosome proteins were also identified in these complexes. Each tagged complex catalyzed both precleaved insertion and deletion editing in vitro. However, KREN1 complexes cleaved deletion but not insertion editing sites in vitro, and, conversely, KREN2 complexes cleaved insertion but not deletion editing sites. These specific nuclease activities were abolished by mutations in the putative RNase III catalytic domain of the respective proteins. Thus editosomes appear to be heterogeneous in composition with KREN1 complexes catalyzing cleavage of deletion sites and KREN2 complexes cleaving insertion sites while both can catalyze the U addition, U removal, and ligation steps of editing.