[摘要]：We describe the synthesis and silencing activities of siRNA possessing N-1-[3,5-bis(hydroxymethyl) phenyl] thymine (b(t)) in their 3'-overhang regions. We found that an siRNA possessing b(t) in the 3'-overhang region was more effective than an siRNA with natural nucleosides and the siRNA possessing 1,3-bis(hydroxymethyl) benzene (b) without a nucleobase at the 3'-overhang region in in vitro experiment using HeLa cells system. Furthermore, the RNA possessing b(t) at its 3'-end was more resistant to nucleolytic hydrolysis by snake venom phosphodiesterase (a 3'-exonuclease) than the RNA possessing the natural nucleoside 2'-deoxythymidine at the 3'-end. Thus, the compound b(t) will be a novel 3'-overhang moiety that can enhance the silencing activity and nuclease-resistant property of siRNAs. (C) 2008 Elsevier Ltd. All rights reserved.
