The ability to synthesize capped RNA transcripts in vitro has been of considerable value in a variety of applications. However, one-third to one-half of the caps have, until now, been incorporated in the reverse orientation. Such reverse caps impair the translation of in vitro-synthesized mRNAs. Novel cap analogues, such as P1-3′-deoxy-7-methylguanosine-5′P3-guanosine-5′triphosphate and P1-3′-O,7-dimethylguanosine-5′P3-guanosine-5′triphosphate, have been designed that are incapable of being incorporated into RNA in the reverse orientation. Transcripts produced with SP6 polymerase using “anti-reverse” cap analogues were of the predicted length. Analysis of the transcripts indicated that reverse caps were not formed. The in vitro translational efficiency of transcripts with the novel “anti-reverse” cap analogues was significantly higher than that of transcripts formed with conventional caps.
能够在体外合成带帽的RNA转录本,在各种应用中具有相当大的价值。然而,到目前为止,三分之一到一半的帽子都是以相反的方向合成的。这些反向帽会影响体外合成的mRNA的翻译。设计了新型的帽子类似物,例如P1-3'-去氧-
7-甲基鸟苷-5'P3-
鸟苷-5'
三磷酸和P1-3'-O,7-二甲基
鸟苷-5'P3-
鸟苷-5'
三磷酸,它们无法以相反的方向被合成到RNA中。使用“反向”帽子类似物的
SP6聚合酶产生的转录本长度符合预期。对转录本的分析表明未形成反向帽。使用新型“反向”帽子类似物形成的转录本的体外翻译效率显著高于使用传统帽子形成的转录本。