Coding and Noncoding RNAs A Versatile RNA Vector for Delivery of

hecapacitytodeliverforeignRNAtoaspecifictissueofinter-est is a significant barrier preventing the therapeutic transla-tionofmanybasicsciencediscoveries.Thisisperhapsbestexem-plified with RNA interference (RNAi). RNAi has the capacity torepress expression of a desired transcript through recruitment ofeffector protein complexes by complementary small RNAs (1).The level of RNAi-mediated posttranscriptional silencing is gen-erallydeterminedbytheamountofcomplementaritybetweenthesmall RNA and its target. Endogenous microRNAs (miRNAs)generally repress gene expression 2- to 3-fold due to imperfectcomplementarity to the target gene sequence (2). However, thesilencing capacity of perfectly complementary small RNAs, suchasengineeredartificialmiRNAs(amiRNAs),issignificantlyhigher(3–5), providing a promising strategy for therapeutics. Unfortu-nately,efficient