Horváth A, Berry E A, Maslov D A
Department of Biology, University of California, Riverside, CA 92521, USA.
Science. 2000 Mar 3;287(5458):1639-40. doi: 10.1126/science.287.5458.1639.
The type of RNA editing found in the kinetoplast-mitochondria of trypanosomes and related protozoa, involving uridylate insertions and deletions, creates translatable messenger RNAs (mRNAs) out of nonsense pre-edited RNAs by correcting encoded defects that vary from simple frameshifts to large "cryptic" regions. However, any evidence for translation of these mRNAs in the kinetoplast has been missing for decades. We identified a kinetoplast-encoded protein, apocytochrome b, whose mRNA is edited in the 5' region. The determined amino-terminal sequence of the protein coincides with the predicted sequence derived from the edited region, demonstrating that the cognate apocytochrome b mRNA is translated into a functional protein. This finding represents the first direct evidence for a functional translation system in the kinetoplasts.
在锥虫和相关原生动物的动质体线粒体中发现的RNA编辑类型，涉及尿苷酸的插入和缺失，通过纠正从简单移码到大型“隐蔽”区域等编码缺陷，从无义的预编辑RNA中产生可翻译的信使RNA（mRNA）。然而，几十年来一直没有这些mRNA在动质体中翻译的任何证据。我们鉴定出一种动质体编码的蛋白质——脱辅基细胞色素b，其mRNA在5'区域进行编辑。所确定的该蛋白质的氨基末端序列与从编辑区域推导的预测序列一致，表明同源的脱辅基细胞色素b mRNA被翻译成了一种功能性蛋白质。这一发现代表了动质体中功能性翻译系统的首个直接证据。
