Harnessing Deaminated DNA to Modulate mRNA Translation for Controlled and Sequential Protein Expression

Abstract Messenger RNA (mRNA) offers transformative potential in vaccines and therapeutics for a range of intractable diseases. While considerable efforts have focused on enhancing protein expression levels to improve efficacy, comparatively little attention has been given to regulating the rate and timing of protein expression. Given that sudden antigen bursts can overstimulate immune responses and pose serious risks in susceptible individuals, precise control over translation kinetics is essential for safe and personalized mRNA therapies. Herein, we describe the use of “damaged” DNA to modulate translation rates of mRNAs. Hybridization of deoxyuridine‐containing DNA to the 5′‐end of mRNA inhibits translation initiation, which is subsequently displaced via base excision repair (BER), enabling controlled expression. DNA strand lengths determine the rate and onset of translation (e.g., a 52‐nt DNA induces a 20‐fold slower expression with a 200‐min delay). This also enables the sequential expression of multiple mRNAs from a single cocktail. This strategy requires no chemical modification of the mRNA and produces no toxic byproducts, but only recyclable DNA fragments—offering a broadly applicable and biocompatible adjuvant for controlled mRNA translation.