The dual-EMCV IRES configuration enhanced circRNA translation efficiency up to approximately 2.1-fold relative to the highest single-IRES construct in HEK293T cells.
A dual-IRES strategy using EMCV-derived elements enhances the translation efficiency of circular RNA, offering a promising approach to optimize circRNA vectors for drug delivery.
Effect estimate: 2.1-fold increase (dual-EMCV-6A+EMCV-∆DI vs single iEV-B107)
Absolute Event Rate: 1436.21% vs 656.64%
p-value: p=<0.0001
Circular RNA (circRNA) has emerged as a promising vector for drug delivery because, unlike linear mRNA, it does not require costly chemical modifications and offers greater stability and sustained expression in cells. Lacking the canonical 5′ cap structure, circRNA relies primarily on internal ribosome entry sites (IRES) to initiate translation, but IRES-mediated initiation is less efficient than cap-dependent translation. To overcome this limitation, we devised a dual-IRES strategy that introduces a second IRES to drive translation of the coding sequence (CDS). By testing several IRES elements known for high translational activity, this study shows that IRESs derived from the EMCV (Encephalomyocarditis virus) family can enhance expression when placed at the 3′ of the CDS, in coordination with the 5′ EMCV-derived IRES. The optimal dual-IRES combinations identified in this study display compatibility with two different coding sequences, offering a useful strategy to enhance circRNA translation.
Sun et al. (Wed,) conducted a other in HEK293T cells used for in vitro transfection experiments evaluating circular RNA translation efficiency. Dual-IRES circular RNA constructs, primarily EMCV-6A leading combinations with second IRES of EMCV-∆DI, EMCV-7A, EMCV-6A or EMCV-∆ATG11 vs. Single-IRES circular RNA constructs including EMCV-∆ATG11, EMCV-6A, HRV, EV-A71, CVB3, and iEV-B107 was evaluated on Protein translation efficiency as measured by EGFP fluorescence and NanoLuc luciferase activity in HEK293T cells (2.1-fold increase (dual-EMCV-6A+EMCV-∆DI vs single iEV-B107), p=<0.0001). The dual-EMCV IRES configuration enhanced circRNA translation efficiency up to approximately 2.1-fold relative to the highest single-IRES construct in HEK293T cells.