1. The RNA–RNA base pairing potential of human Dicer and Ago2 proteins
- Author
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Marek C. Milewski, Maria Pokornowska, Ziemowit Radogostowicz, Marek Figlerowicz, Anna Kurzynska-Kokorniak, Kinga Ciechanowska, Agnieszka Szczepanska, and Marta Wojnicka
- Subjects
Ribonuclease III ,Small RNA ,genetic processes ,RNA-annealing activity ,RNA-binding proteins ,DEAD-box RNA Helicases ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,mRNA fate ,microRNA ,Gene expression ,Annealing activity ,Gene silencing ,Humans ,RNA-Induced Silencing Complex ,Nucleic acid structure ,Molecular Biology ,Base Pairing ,Translational regulator ,030304 developmental biology ,Pharmacology ,0303 health sciences ,biology ,Chemistry ,RNA annealers ,030302 biochemistry & molecular biology ,fungi ,RNA ,food and beverages ,Cell Biology ,Cell biology ,enzymes and coenzymes (carbohydrates) ,Gene Expression Regulation ,miRNA/siRNA pathways ,Argonaute Proteins ,biology.protein ,Molecular Medicine ,Original Article ,Dicer ,Protein Binding - Abstract
The ribonuclease Dicer produces microRNAs (miRNAs) and small interfering RNAs that are handed over to Ago proteins to control gene expression by targeting complementary sequences within transcripts. Interestingly, a growing number of reports have demonstrated that the activity of Dicer may extend beyond the biogenesis of small regulatory RNAs. Among them, a report from our latest studies revealed that human Dicer facilitates base pairing of complementary sequences present in two nucleic acids, thus acting as a nucleic acid annealer. Accordingly, in this manuscript, we address how RNA structure influences the annealing activity of human Dicer. We show that Dicer supports hybridization between a small RNA and a complementary sequence of a longer RNA in vitro, even when both complementary sequences are trapped within secondary structures. Moreover, we show that under applied conditions, human Ago2, a core component of RNA-induced silencing complex, displays very limited annealing activity. Based on the available data from new-generation sequencing experiments regarding the RNA pool bound to Dicer in vivo, we show that multiple Dicer-binding sites within mRNAs also contain miRNA targets. Subsequently, we demonstrate in vitro that Dicer but not Ago2 can anneal miRNA to its target present within mRNA. We hypothesize that not all miRNA duplexes are handed over to Ago proteins. Instead, miRNA-Dicer complexes could target specific sequences within transcripts and either compete or cooperate for binding sites with miRNA-Ago complexes. Thus, not only Ago but also Dicer might be directly involved in the posttranscriptional control of gene expression. Electronic supplementary material The online version of this article (10.1007/s00018-019-03344-6) contains supplementary material, which is available to authorized users.
- Published
- 2019