Regulation of miRNA content. Part 1. Editing miRNA. Тailing miRNA

This scientific review presents the processes of regulation of miRNA content. To write the article, information was searched using Scopus, Web of Science, MedLine, PubMed, Google Scholar, EMBASE, Global Health, The Cochrane Library, CyberLeninka databases. The article presents the characteristics of the processes of microRNA editing and microRNA tailing, which regulate the content of microRNA through the transcription control. It is emphasized that editing is the most important mechanism of posttranscriptional regulation of microRNA that occurs with the help of RNA-specific adenosine deaminase. The article shows that editing leads to a change in the secondary structure of the microRNA molecule and the deviation of the process of microRNA maturation. It is shown that microRNA tailing is a posttranscriptional elongation of the tail of the molecule by adding nucleotides to the 3’-end of RNA. It has been found that uridinylation is a very common posttranscriptional process that regulates gene expression. The effect of uridinylation on microRNA biogenesis has been demonstrated on the example of the miR let-7 family, which inhibits proliferation and promotes cell differentiation. It has been established that another type of microRNA tailing, namely adenylation, most often contributes to the stabilization of the molecule, but in some cases can lead to microRNA degradation. Thus, the regulation of miRNA content is carried out by editing miRNA, microRNA tailing. Due to editing, the secondary structure of the microRNA molecule changes and the microRNA maturation process deviates. MicroRNA tailing is a post-transcriptional elongation of the tail of the molecule by adding nucleotides to the 3’-end of RNA by polyuridinylation or polyadenylation. Uridinylation affects the processing and degradation of miRNA precursors with different molecular effects, which in some cases contribute to the development of diseases.