The microRNA and the perspectives of miR-302

Abstract

MiRNAs are naturally occurring, small, non-coding RNA molecules that post-transcriptionally regulate the expression of a large number of genes involved in various biological processes, either through mRNA degradation or through translation inhibition. MiRNAs play important roles in many aspects of physiology and pathology throughout the body, particularly in cancer, which have made miRNAs attractive tools and targets for translational research. The types of non-coding RNAs, biogenesis of miRNAs, circulating miRNAs, and direct delivery of miRNA were briefly reviewed. As a case of point, the role and perspective of miR-302, a family of ES-specific miRNA, on cancer, iPSCs, heart disease were presented.

Keywords: Biochemistry; Biomedical engineering; Biotechnology; Cancer research; Cell biology; Developmental biology; Genetics; Molecular biology.

Fig. 1

The biogenesis of intronic miRNA miR-302. Encoded in the intronic region of the La Ribonucleoprotein domain family member 7 gene (LARP7 or PIP7S), miR-302 is a native intronic miRNA. First, transcribed within the intron of LARP7 gene transcripts by type-II RNA polymerases, and then cellular spliceosomes splice the intron out of LARP7 gene transcripts to form primary miRNA precursors, pri-miRNAs (pri-miR-302). After that, Drosha-like endoribonucleases process the pri-miRNAs into miRNA precursors (pre-miRNAs) with a single hairpin like structure. Then, Exportin-5 exports the pre-miRNAs out of the nucleus into the cytoplasm allowing Dicer-like RnaseIII endoribonucleases to further process and form 21–23nt long mature miRNAs, such as miR-302s. Lastly, following assembly into RNA-induced silencing complexes (RISC) with Argonaute proteins, the mature miR-302s carry out their specific gene silencing functions.