MicroRNAs: Small Regulators of Tissue Regeneration

MiRNAs are defined as a small non coding RNA molecules about 22 nucleotides in length (1). Regularly cell use these molecules to control translation of mRNA to related protein called post-transcriptional regulation of gene expression. MiRNAs are not specific for animal kingdom because they reported in plants and also some viruses (2, 3). MiRNAs can attach to their target mRNAs using complementary hydrogen bounds between nucleotides. After bonding RNA induced silencing complex (RISC) is triggered, the cleavage and degradation of mRNA being started so protein production will be inhibited (4). In another strategy pairing of miRNA and mRNA lead to less translation of mRNA by ribosomes. As a result, both methods reduce the amount of protein production in the cell. First miRNA discovery has been reported in 1990s (5). During this 25 years so many member of this family have been discovered. Today it is good understood that they have important roles in different cellular process and clinical importance including cancer (6), as a diagnosis tools or biomarkers (7) or even neurogenesis (8), and stem cells function such as differentiation, self-renewal and paracrine effects (9) and subsequently tissue regeneration (10). MiRNA fine tuning and regulation and its role in cell fate demonstrated in Figure 1. ABSTRACT