Salavati Reza, Ernst Nancy Lewis, O'Rear Jeff, Gilliam Troy, Tarun Salvador, Stuart Kenneth
Seattle Biomedical Research Institute, Washington 98109-5219, USA.
RNA. 2006 May;12(5):819-31. doi: 10.1261/rna.2244106. Epub 2006 Apr 6.
The 20S editosome, a multiprotein complex, catalyzes the editing of most mitochondrial mRNAs in trypanosomatids by uridylate insertion and deletion. RNAi mediated inactivation of expression of KREPA4 (previously TbMP24), a component of the 20S editosome, in procyclic form Trypanosoma brucei resulted in inhibition of cell growth, loss of RNA editing, and disappearance of 20S editosomes. Levels of MRP1 and REAP-1 proteins, which may have roles in editing but are not editosome components, were unaffected. Tagged KREPA4 protein is incorporated into 20S editosomes in vivo with no preference for either insertion or deletion subcomplexes. Consistent with its S1-like motif, recombinant KREPA4 protein binds synthetic gRNA with a preference for the 3' oligo (U) tail. These data suggest that KREPA4 is an RNA binding protein that may be specific for the gRNA Utail and also is important for 20S editosome stability.
20S编辑体是一种多蛋白复合体，通过尿苷酸的插入和缺失催化锥虫中大多数线粒体mRNA的编辑。RNA干扰介导的20S编辑体组分KREPA4（以前称为TbMP24）在布氏锥虫前循环形式中的表达失活，导致细胞生长受到抑制、RNA编辑丧失以及20S编辑体消失。可能在编辑中起作用但不是编辑体组分的MRP1和REAP-1蛋白水平未受影响。带有标签的KREPA4蛋白在体内被整合到20S编辑体中，对插入或缺失亚复合体没有偏好。与其S1样基序一致，重组KREPA4蛋白结合合成的引导RNA，对3'寡聚（U）尾有偏好。这些数据表明，KREPA4是一种RNA结合蛋白，可能对引导RNA的U尾具有特异性，并且对20S编辑体的稳定性也很重要。
