Specific inhibition of gene expression by small double-stranded RNAs in invertebrate and vertebrate systems

TLDR

Short interfering RNAs (siRNAs) are 21–25‑nt double‑stranded RNAs that trigger sequence‑specific RNA degradation in plants and RNA interference in invertebrates, and they possess 5′‑phosphate/3′‑hydroxyl ends with a 2‑base 3′ overhang on each strand. The study aims to show that synthetic siRNAs can specifically inhibit gene expression. The authors tested synthetic siRNAs in Caenorhabditis elegans and in human and mouse cell lines. siRNAs outperformed antisense oligonucleotides, avoided the nonspecific effects of longer dsRNAs, and point to their use as a reverse‑genetic and therapeutic tool in mammalian cells.

Abstract

Short interfering RNAs (siRNAs) are double-stranded RNAs of ≈21–25 nucleotides that have been shown to function as key intermediaries in triggering sequence-specific RNA degradation during posttranscriptional gene silencing in plants and RNA interference in invertebrates. siRNAs have a characteristic structure, with 5′-phosphate/3′-hydroxyl ends and a 2-base 3′ overhang on each strand of the duplex. In this study, we present data that synthetic siRNAs can induce gene-specific inhibition of expression in Caenorhabditis elegans and in cell lines from humans and mice. In each case, the interference by siRNAs was superior to the inhibition of gene expression mediated by single-stranded antisense oligonucleotides. The siRNAs seem to avoid the well documented nonspecific effects triggered by longer double-stranded RNAs in mammalian cells. These observations may open a path toward the use of siRNAs as a reverse genetic and therapeutic tool in mammalian cells.