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.