RNA Enhancement by lncRNA Promotes Translation Through Recruitment of ILF3 and EIF4A1 to the Target Mammalian mRNAs

Abstract

The previously developed technology RNA enhancement (RNAe) is reported to increase specific gene expression at post-transcriptional level via a long noncoding RNA (lncRNA). The mechanism for SINEB2-dependent enhancement of translation remains not well understood. Here we present the result of experiments with the folded states of lncRNA in doubly deionized water obtained by slowcool method. These lncRNA were used in RNA pull-down assay that yielded six lncRNA-binding proteins potentially involved in RNAe. The direct interactions of lncRNA with interleukin enhancer-binding factor 3 (ILF3) and eukaryotic initiation factor 4A-I (eIF4A1) in vivo and in vitro were confirmed in RNA-binding protein affinity experiment and electrophoretic mobility shift assay (EMSA), respectively. These observations could explain RNAe phenomenon through lncRNA-dependent guiding of ILF3 protein, which, in turn, recruits polysomes or the factors for translation initiation, and attracting eIF4A1 proteins accelerating the unwinding of the secondary structure at the 5'-end of mRNA during translation initiation. Therefore, the hypothetical mechanism through which lncRNAs may regulate the translation of a specific mRNA is proposed.