4′-C-Aminoethoxy modification enhanced nuclease resistance of RNAs and improved thermal stability of RNA duplexes

Abstract We designed and synthesized RNAs containing 4′-C-aminoethoxy-2′-O-methyluridine (4′-AEoU), and compared their properties with those containing 4′-C-aminopropyl-2′-O-methyluridine (4′-APU). The RNA duplexes containing 4′-AEoU showed higher melting temperatures than those containing 4′-APU. The 4′-AEoU modification enhanced the stability of the RNAs in buffer containing serum. Furthermore, it was found that the incorporation of 4′-AEoU into the passenger strand of small interfering RNAs (siRNAs) is tolerated for the RNA interference (RNAi) activity of the siRNAs.