Regulation of miRNA content. Part 2. Degradation of miRNAs

Abstract

The scientific review presents the process of regulation of microRNA content — microRNA degradation. To write the article, information was searched using databases Scopus, Web of Science, MedLine, PubMed, Google Scholar, EMBASE, Global Health, The Cochrane Library, CyberLeninka. The article presents the characteristics of the most important process of RNA metabolism — degradation of 3'→5' RNA. Degradation of microRNA is inherent in organisms of all kingdoms of life and is involved in the regulation of RNA representation, elimination of dysfunctional or incorrectly constructed RNA molecules and processing of RNA precursors. Exoribonucleases that affect the stability of mature forms of miRNA are presented. It is emphasized that XRN exoribonucleases degrade various RNA substrates during total RNA degradation and are involved in specific processes such as nonsense-mediated degradation, gene silencing, rRNA maturation, and transcription termination. It is shown that exoribonuclease XRN2 plays a crucial role in the termination of transcription during viral infection, namely it has cytoplasmic antiviral activity against hepatitis C virus. The role of RNA-degrading exosome in microRNA degradation is presented. RNA-degrading exosome is a ubiquitous complex and 3'-5'-endo- and exoribonucleases of eukaryotes, which interacts with several processing cofactors and degrades almost all classes of cytoplasmic RNA. The article reflects the function of evolutionarily conserved phosphorolytic 3'-5'-exoribonuclease — polynucleotide phosphorylase. The role of exoribonuclease 1, which is an evolutionarily conserved 3'-5'-exoribonuclease of the DEDDh family, is involved in the final processing of 5.8S rRNA, replication-dependent histone mRNA, siRNA, and miRNA. Eri1 exoribonuclease has been shown to regulate global microRNA homeostasis in lymphocytes and to participate in NK cell development and antiviral response. Thus, one of the mechanisms of regulation of miRNA content is the most important process of RNA metabolism, which is inherent in organisms of all kingdoms of life, namely the degradation of miRNAs.