Key words: miRNAs, IsomiRs
Mature microRNAs (miRNAs), average length of 22 nucleotides, are expressed ubiquitously and regulate many essential biological processes and pathological conditions mainly via post transcriptional silencing through mRNA decay and/or translational repression . Recently, Next-Generation Sequencing (NGS) technology has revealed that miRNA frequently exhibit differences from their corresponding reference mature sequences, generating multiple variants specifically abbreviated as microRNA isoforms (isomiRs) . Isoforms are generated either due to imprecise miRNAs precursor cleavage, terminal trimming or the addition of non-templated nucleotide via exoribonuclease or nucleotidyl transferase activity. IsomiRs are functional in influence the miRNA stability, sub-cellular localization and target selection [3-5].