Identification of Novel miRNAs Encoded by MSI۱ Gene Using Bioinformatic andExperimental Methods

miRNAs play critical roles in many cellular processes and developmental pathways. It isdocumented that aberrant expression of miRNAs is associated with several disorders [۱]. RNA-bindingprotein Musashi۱ (MSI۱) shows an increased expression level in several cancers and has beenintroduced as a prognostic marker in some malignancies [۲]. It is expected that if any miRNA is encodedby this gene, it might have a role in cancer development or could be considered as a prognosticbiomarker. Accordingly, in this study, we aimed to find novel miRNA(s) inside the intronic regions ofthe MSI۱ gene. For discovery of novel miRNAs, several approaches including experimental andcomputation-driven methods are employed [۳]. In this study we used the combination of bothexperimental and computation-driven methods to discover novel miRNAs inside MSI۱ gene. Weemployed several bioinformatics software to predict novel miRNA precursors, evaluate the ability ofproducing mature miRNAs by predicted stem-loop structures and predict target genes for the potentialmature miRNAs. Among several miRNA precursors predicted by bioinformatics studies, we selectedtwo precursors within intron ۴ of MSI۱ gene, named MSM۲ and MSM۳. For experimental analysis,corresponding precursor miRNAs were transfected into HEK۲۹۳T cells and exogenous expression ofthe mature miRNAs were detected by RT-qPCR and sequencing analysis. Two mature miRNAs,MSM۳-۳p and MSM۳-۵p were generated by MSM۳ precursor and one, MSM۲-۵p, was derived fromMSM۲. Moreover, endogenous expression of MSM۲-۵p and MSM۳-۳p was detected in MCF-۷ andSH-SY۵Y cell lines. Additionally, the interaction between the MSM۳-۳p and ۳′UTR region of PDE۱۱Awas confirmed by using luciferase assay. Overall, our data demonstrated that MSI۱ gene encodes twonovel miRNAs.

Keywords:

Novel miRNAs , MSI۱ gene , Cancer , Bioinformatics