Walters Robert W, Matheny Tyler, Mizoue Laura S, Rao Bhalchandra S, Muhlrad Denise, Parker Roy
Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO 80303.
Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80303.
Proc Natl Acad Sci U S A. 2017 Jan 17;114(3):480-485. doi: 10.1073/pnas.1619369114. Epub 2016 Dec 28.
RNAs besides tRNA and rRNA contain chemical modifications, including the recently described 5' nicotinamide-adenine dinucleotide (NAD) RNA in bacteria. Whether 5' NAD-RNA exists in eukaryotes remains unknown. We demonstrate that 5' NAD-RNA is found on subsets of nuclear and mitochondrial encoded mRNAs in Saccharomyces cerevisiae NAD-mRNA appears to be produced cotranscriptionally because NAD-RNA is also found on pre-mRNAs, and only on mitochondrial transcripts that are not 5' end processed. These results define an additional 5' RNA cap structure in eukaryotes and raise the possibility that this 5' NAD cap could modulate RNA stability and translation on specific subclasses of mRNAs.
除了转运RNA（tRNA）和核糖体RNA（rRNA）之外，核糖核酸（RNA）还含有化学修饰，包括细菌中最近描述的5'-烟酰胺腺嘌呤二核苷酸（NAD）RNA。真核生物中是否存在5'-NAD-RNA仍然未知。我们证明，在酿酒酵母中，5'-NAD-RNA存在于核编码和线粒体编码的信使核糖核酸（mRNA）亚群上。NAD-mRNA似乎是在转录过程中产生的，因为在信使前体核糖核酸（pre-mRNA）上也发现了NAD-RNA，并且仅在线粒体转录本上发现，这些转录本的5'端未经过加工。这些结果定义了真核生物中一种额外的5'RNA帽结构，并增加了这种5'-NAD帽可能调节特定mRNA亚类的RNA稳定性和翻译的可能性。
