Hemophilia Cured in Mice
Gene therapy involves substituting or introducing a therapeutic gene to replace or accompany the defective one. Many previous attempts at gene therapy have utilized retroviruses, however the main pitfall of retroviruses is that scientists cannot control where the therapeutic gene will be inserted. This is a huge drawback as the therapeutic gene might be inserted in a potentially useful or necessary part of the genome, which could lead to even more genetic mutation.
|by ICSident (CC License) via Wikimedia|
Recently, a team of scientists led by Dr Holmes and Dr High used a zinc finger nuclease to repair hemophilia in mice. Zinc finger nucleases don’t actually exist in nature and are engineered from a fusion of a Zinc finger domain and a nuclease. Zinc Finger domains are typically found in transcription factors (proteins which help to control the rate of transcription of RNA from DNA) because they recognize and interact with very specific sections of DNA. Nucleases on the other hand as their name implies are involved in cutting the Nucleic acids.
Typically, scientists have used the ZFNs to specifically induce a double stranded break in the DNA, this in turn recruits the DNA repair mechanisms. The Holmes/High team co-delivered a gene targeting vector which allowed them to replace the broken hemophilia gene with a good one. This is amazing, and raises the possibility of targeted gene-editing as a therapy for genetic diseases.