IsomiRs have functional importance.
Since the inception of deep sequencing, isomiRs are consistently observed to be produced by most miRNA genes in a variety of cell types. IsomiRs appear as a variation in length from the canonical sequence annotated in miRBase, due to an addition or deletion of one or more nucleotides at the 5(') or 3(') ends or both. As the seed sequence is located at the 5(') end of the microRNA, the target mRNA will be theoretically different. Therefore, 5(')isomiRs might potentially target a new set mRNA compared to their canonical counterpart. This article gives an overview of investigations that explored the functional potential of isomiRs such as their ability to incorporate into Argonaute protein, the differential expression of isomiRs in various tissue types and cell lines, and the differences of mRNA targets between isomiR and its canonical microRNA. In addition, this article provides a brief introduction of RNA sponges as a potential way to inhibit isomiRs.
Universiti Kebangsaan Malaysia Medical Centre, Department of Pathology, Jalan Yaacob Latif, Bandar Tun Razak, 56000 Cheras, Kuala Lumpur, Malaysia. tan_geok_chin@yahoo.com.
Geok Chin
GC
Tan
Nicholas
N
Dibb
D000818:Animals; D001483:Base Sequence; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D059367:RNA Cleavage / Q000235:genetics*
D035683:MicroRNAs