Chemical modification of RNA duplexes can provide practical advantages for RNA interference (RNAi) triggering molecules including increased stability, safety and specificity. The impact of nucleotide modifications on Dicer processing, RISC loading and RNAi-mediated mRNA cleavage was investigated with duplexes ≥25 bp in length. It is known that dsRNAs ≥25 bp are processed by Dicer to create classic 19-bp siRNAs with 3′-end overhangs. We demonstrate that the presence of minimal modification configurations on longer RNA duplexes can block Dicer processing and result in the loading of the full-length guide strand into RISC with resultant mRNA cleavage at a defined site. These longer, modified duplexes can be highly potent gene silencers, with EC50s in the picomolar concentration range, demonstrating that Dicer processing is not required for incorporation into RISC or potent target silencing.
展开▼
机译：RNA双链体的化学修饰可为RNA干扰（RNAi）触发分子提供实用的优势，包括增加的稳定性，安全性和特异性。在长度≥25 bp的双链体中，研究了核苷酸修饰对Dicer加工，RISC加载和RNAi介导的mRNA切割的影响。已知Dicer对≥25 bp的dsRNA进行了处理，以创建具有3'末端突出端的经典19 bp siRNA。我们证明在较长的RNA双链体上的最小修饰配置的存在可以阻止Dicer加工，并导致全长导向链加载到RISC中，从而在限定的位点产生mRNA裂解。这些更长的修饰双链体可能是高效的基因沉默子，EC50处于皮摩尔浓度范围，表明掺入RISC或有效的靶标沉默不需要Dicer加工。
展开▼
