Effect of Sugar 2',4'-Modifications on Gene Silencing Activity of siRNA Duplexes.
In this study, we explore the effect of a library of 2'-, 4'-, and 2',4'-modified uridine nucleosides and their impact on silencing firefly luciferase and on down-regulated in renal cell carcinoma (DRR) gene targets. The modifications studied were 2'-F-ribose, 2'-F-arabinose, 2'-OMe-ribose, 2'-F,4'-OMe-ribose, 2'-F,4'-OMe-arabinose, and 2'-OMe,4'-F-ribose. We found that 2',4'-modifications are well tolerated within A-form RNA duplexes, leading to virtually no change in melting temperature as assessed by UV thermal melting. The impact of the dual (2',4') modification was assessed by comparing gene silencing ability to 2'- or 4'- (singly) modified siRNA counterparts. siRNAs with (2',4')-modified overhangs generally outperformed the native siRNA as well as siRNAs with a 2'- or 4'-modified overhang, suggesting that 2',4'-modified nucleotides interact favorably with Argonaute protein's PAZ domain. Among the most active siRNAs were those with 2'-F,4'-OMe-ribose or 2'-F,4'-OMe-arabinose at the overhangs. When modifications were placed at both overhangs and internal positions, a duplex with the 2'-F (internal) and 2'-F,4'-OMe (overhang) combination was found to be the most potent, followed by the duplex with 2'-OMe (internal) and 2',4'-diOMe (overhang) modifications. Given the nuclease resistance exhibited by 2',4'-modified siRNAs, particularly when the modification is placed at or near the overhangs, these findings may allow the creation of superior siRNAs for therapy.
['Malek-Adamian|Elise|E|', 'Fakhoury|Johans|J|', 'Arnold|Amy E|AE|', 'Martínez-Montero|Saúl|S|', 'Shoichet|Molly S|MS|', 'Damha|Masad J|MJ|']
D060565:Argonaute Proteins D020868:Gene Silencing D006801:Humans D008958:Models, Molecular D009690:Nucleic Acid Conformation D009711:Nucleotides D034622:RNA Interference D012330:RNA, Double-Stranded D034741:RNA, Small Interfering D000073893:Sugars D014529:Uridine
RNAi oligonucleotide synthesis ribose-modified siRNA