Hsa-miR-422a Originated from Short Interspersed Nuclear Element Increases Expression by Collaborating with NF-E2.

MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulate the expression of target messenger RNA (mRNA) complementary to the 3' untranslated region (UTR) at the post-transcriptional level. Hsa-miR-422a, which is commonly known as miRNA derived from transposable element (MDTE), was derived from short interspersed nuclear element (SINE). Through expression analysis, hsa-miR-422a was found to be highly expressed in both the small intestine and liver of crab-eating monkey. AT-Rich Interaction Domain 5 B () was selected as the target gene of hsa-miR-422a, which has two binding sites in both the exon and 3'UTR of . To identify the interaction between hsa-miR-422a and , a dual luciferase assay was conducted in HepG2 cell line. The luciferase activity of cells treated with the hsa-miR-422a mimic was upregulated and inversely downregulated when both the hsa-miR-422a mimic and inhibitor were administered. Nuclear factor erythroid-2 (NF-E2) was selected as the core transcription factor (TF) via feed forward loop analysis. The luciferase expression was downregulated when both the hsa-miR-422a mimic and siRNA of NF-E2 were treated, compared to the treatment of the hsa-miR-422a mimic alone. The present study suggests that hsa-miR-422a derived from SINE could bind to the exon region as well as the 3'UTR of . Additionally, hsa-miR-422a was found to share binding sites in with several TFs, including NF-E2. The hsa-miR-422a might thus interact with TF to regulate the expression of , as demonstrated experimentally. Altogether, hsa-miR-422a acts as a super enhancer miRNA of by collaborating with TF and NF-E2.