Dual-localization signals enhance mitochondrial targeted presentation of engineered proteins.

Effective delivery of engineered proteins into mitochondria is of great significance for developing efficient mitochondrial DNA editing tools and realizing accurate treatment of mitochondrial diseases. Here, the candidate genes, eGFP and Cas9, were engineered with different mitochondrial localization signal (MLS) sequences introduced at their up- or/and down-streams. The corresponding expression vectors for the engineered proteins were constructed respectively, and HEK293T cells were transfected with these vectors. The fluorescence colocalization and Western blotting assays were used to analyze the mitochondrial targeting presentation effect of different engineered proteins. The results demonstrated that the daul-MLS modification of the eGFP and Cas9 proteins significantly improved the efficiency of mitochondrial targeted presentation, compared with the engineered proteins with single MLS added. Hence, it is speculated that dual MLS strategy can enhance the mitochondrial targeting of engineered proteins, which lays a theoretical foundation for the future development of efficient mitochondrial DNA editing tools.