Tarun Salvador Zipagan, Schnaufer Achim, Ernst Nancy Lewis, Proff Rosemary, Deng Junpeng, Hol Wim, Stuart Kenneth
Seattle Biomedical Research Institute, Seattle, Washington 98109, USA
RNA. 2008 Feb;14(2):347-58. doi: 10.1261/rna.763308. Epub 2007 Dec 7.
Most mitochondrial mRNAs in kinetoplastid protozoa require post-transcriptional RNA editing that inserts and deletes uridylates, a process that is catalyzed by multiprotein editosomes. KREPA6 is the smallest of six editosome proteins that have predicted oligonucleotide-binding (OB) folds. Inactivation of KREPA6 expression results in disruption and ultimate loss of approximately 20S editosomes and inhibition of procyclic form cell growth. Gel shift studies show that recombinant KREPA6 binds RNA, but not DNA, with a preference for oligo-(U) whether on the 3' end of gRNA or as a (UU)(12) homopolymer. Thus, KREPA6 is essential for the structural integrity and presence of approximately 20S editosomes and for cell viability. It functions in RNA binding perhaps primarily through the gRNA 3' oligo(U) tail. The significance of these findings to key steps in editing is discussed.
动质体原生动物中的大多数线粒体mRNA需要进行转录后RNA编辑，即插入和删除尿苷酸，这一过程由多蛋白编辑体催化。KREPA6是六种预测具有寡核苷酸结合（OB）折叠的编辑体蛋白中最小的一种。KREPA6表达的失活会导致约20S编辑体的破坏并最终丧失，以及抑制前循环形式细胞的生长。凝胶迁移实验表明，重组KREPA6结合RNA而非DNA，对gRNA 3'端的寡聚（U）或（UU）(12) 同聚物形式的寡聚（U）具有偏好性。因此，KREPA6对于约20S编辑体的结构完整性和存在以及细胞活力至关重要。它可能主要通过gRNA 3'端的寡聚（U）尾发挥RNA结合功能。本文讨论了这些发现对编辑关键步骤的意义。
