[Application of artificial DNA-binding proteins and artificial nucleases to prevention of virus infection: development of virus-resistant plants and protein-based anti-viral drugs].

Various DNA viruses are known to cause severe infectious diseases in both plants and mammals, including humans. For many of these infectious diseases, we have yet to find an effective prevention or treatment. Therefore, new methodologies for the prevention of virus infections in both agricultural crops and humans have been vigorously sought for a long time. One attractive approach to the prevention is inhibition of virus replication. We first inhibited virus replication by blocking binding of a viral replication protein, which initiates virus replication, to its replication origin, with using an artificial DNA-binding protein. We demonstrated that this new methodology was very effective in plants and mammalian cells: especially, we created transgenic plants that were immune to a geminivirus. We also developed novel protein-based antiviral drugs by fusing a cell-penetrating peptide to an artificial DNA-binding protein. Furthermore, we successfully generated a more effective protein-based antiviral, which was one hundred thousand times more active than the antiviral chemical drug Cidofovia, by alternatively fusing an DNA-cleaving enzyme to an artificial DNA-binding protein. Since this artificial protein has little cytotoxicity, it is expected that it will be used as a new antiviral drug.