Characterization of the translational regulation of BIM 3’ UTR

Abstract

BIM (BCL-2-interacting mediator of cell death) plays a central role in the regulation of the intrinsic apoptotic pathway by controlling the delicate balance between the induction of apoptosis and cell survival. The dysregulation of BIM expression potentially results in diseases including cancer. Genomic variations of the BIM gene were shown to account for drug resistance. MicroRNAs (miRNA) play a role in post-transcriptional regulation by binding to the messenger RNA (mRNA) 3’ untranslated region (UTR) of protein coding genes which include BIM. Therefore, we are interested in the search for miRNA targets in BIM Exon 5 (E5) 3’ UTR. Previously, 100-nucleotide serial deletions of BIM E5 3’ UTR revealed regulatory clusters. To identify the miRNA targets, deletions of the predicted miRNA targets in the 3’ UTR of BIM E5 were performed using polymerase chain reaction (PCR) mutagenesis and studied using the luciferase reporter assay. The miRNAs showing a significant increase in relative Firefly luciferase activities were further selected for the overexpression assay. The results indicate miR-10 and miR-25 as miRNAs targeting BIM E5 3’ UTR. Thus, future studies are required for further validation of the miRNA targets in BIM E5 3’ UTR that could possibly be intervened for therapeutic purposes.