Frech G C, Bakalara N, Simpson L, Simpson A M
Department of Biology, University of California, Los Angeles 90024.
EMBO J. 1995 Jan 3;14(1):178-87. doi: 10.1002/j.1460-2075.1995.tb06988.x.
A mitochondrial extract from Leishmania tarentolae directs the incorporation of uridylate (U) residues within the pre-edited domain of synthetic cytochrome b (CYb) and NADH dehydrogenase subunit 7 mRNA. This has several characteristics of an in vitro RNA editing activity, but no direct evidence for involvement of guide RNAs was obtained. Inhibition by micrococcal nuclease suggests a requirement for some type of endogenous RNA. The limitation of internal U-incorporation to the pre-edited region in the CYb mRNA and the inhibition by deletion or substitution of both mRNA anchor sequences for CYb gRNA-I and -II could be consistent either with a gRNA-mediated process or a secondary structure-mediated process. A low level of incorporation of [alpha-32P]CTP occurs at the same sites as UTP. Internal U-incorporation activity is selectively inhibited by heterologous RNAs, suggesting an involvement of low affinity RNA-binding proteins which can be competed by the added RNA.
来自热带利什曼原虫的线粒体提取物可引导尿苷酸（U）残基掺入合成细胞色素b（CYb）和NADH脱氢酶亚基7 mRNA的编辑前区域。这具有体外RNA编辑活性的几个特征，但未获得指导RNA参与的直接证据。微球菌核酸酶的抑制作用表明需要某种类型的内源性RNA。CYb mRNA中内部U掺入仅限于编辑前区域，以及CYb gRNA-I和-II的两个mRNA锚定序列的缺失或取代所产生的抑制作用，这既可能与gRNA介导的过程一致，也可能与二级结构介导的过程一致。与UTP相同的位点会发生低水平的[α-32P]CTP掺入。内部U掺入活性被异源RNA选择性抑制，这表明存在低亲和力RNA结合蛋白参与其中，这些蛋白可被添加的RNA竞争。
