RNA interference (RNAi) is an effective mechanism for inhibiting gene expression at the post-transcriptional level. Expression of a messenger RNA (mRNA) can be inhibited by a ∼22-nucleotide (nt) small interfering (si)RNA with the corresponding reverse complementary sequence. Typically, a duplex of siRNA, composed of the desired siRNA and a passenger strand, is processed from a short hairpin RNA (shRNA) precursor by Dicer. Subsequently, one strand of the siRNA duplex is associated with Argonaute (Ago) protein for RNAi. Although RNAi is widely used, the off-target effect induced by the passenger strand remains a potential problem. Here, based on current understanding of endogenous precursor microRNA (pre-miRNA) hairpins, called Ago-shRNA and m7G-capped pre-miRNA, we discuss the principles of shRNA designs that produce a single siRNA from one strand of the hairpin.

中文翻译：

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用于链特异性小干扰 RNA 生产的短发夹 RNA

RNA 干扰 (RNAi) 是一种在转录后水平抑制基因表达的有效机制。信使 RNA (mRNA) 的表达可以被~22 个核苷酸 (nt) 的小干扰 (si) RNA 和相应的反向互补序列抑制。通常，由所需的 siRNA 和过客链组成的 siRNA 双链体是由 Dicer 从短发夹 RNA (shRNA) 前体加工而成的。随后，siRNA 双链体的一条链与用于 RNAi 的 Argonaute (Ago) 蛋白相关。尽管 RNAi 被广泛使用，但由过客链引起的脱靶效应仍然是一个潜在的问题。在这里，基于目前对内源性前体 microRNA (pre-miRNA) 发夹的理解，称为 Ago-shRNA 和 m7G 加帽的 pre-miRNA，