Department of Core Antisense Research, Ionis Pharmaceutics, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA.
Nucleic Acids Res. 2019 Jul 26;47(13):6900-6916. doi: 10.1093/nar/gkz500.
Antisense technology can reduce gene expression via the RNase H1 or RISC pathways and can increase gene expression through modulation of splicing or translation. Here, we demonstrate that antisense oligonucleotides (ASOs) can reduce mRNA levels by acting through the no-go decay pathway. Phosphorothioate ASOs fully modified with 2'-O-methoxyethyl decreased mRNA levels when targeted to coding regions of mRNAs in a translation-dependent, RNase H1-independent manner. The ASOs that activated this decay pathway hybridized near the 3' end of the coding regions. Although some ASOs induced nonsense-mediated decay, others reduced mRNA levels through the no-go decay pathway, since depletion of PELO/HBS1L, proteins required for no-go decay pathway activity, decreased the activities of these ASOs. ASO length and chemical modification influenced the efficacy of these reagents. This non-gapmer ASO-induced mRNA reduction was observed for different transcripts and in different cell lines. Thus, our study identifies a new mechanism by which mRNAs can be degraded using ASOs, adding a new antisense approach to modulation of gene expression. It also helps explain why some fully modified ASOs cause RNA target to be reduced despite being unable to serve as substrates for RNase H1.
反义技术可以通过 RNase H1 或 RISC 途径减少基因表达，并通过调节剪接或翻译来增加基因表达。在这里，我们证明反义寡核苷酸（ASO）可以通过无意义衰变途径发挥作用来降低 mRNA 水平。当针对 mRNA 的编码区时，完全用 2'-O-甲氧基乙基修饰的硫代磷酸酯 ASO 以依赖翻译、不依赖 RNase H1 的方式降低 mRNA 水平。激活这种衰减途径的 ASO 杂交在编码区的 3'端附近。尽管一些 ASO 诱导无义介导的衰变，但其他 ASO 通过无意义衰变途径降低 mRNA 水平，因为耗尽 PELO/HBS1L 蛋白（无意义衰变途径活性所必需的蛋白质）会降低这些 ASO 的活性。ASO 的长度和化学修饰影响这些试剂的功效。这种非 Gapmer ASO 诱导的 mRNA 减少在不同的转录本和不同的细胞系中都观察到。因此，我们的研究确定了一种使用 ASO 降解 mRNA 的新机制，为基因表达的调节增加了一种新的反义方法。它还有助于解释为什么一些完全修饰的 ASO 会导致 RNA 靶标减少，尽管它们不能作为 RNase H1 的底物。
