UCLA researchers have developed a gene editing strategy and methodology based on nuclease-based insertion.
BACKGROUND:
Gene therapies are the forefront of therapeutic advancements for debilitating diseases. However, delivery and insertion of the therapeutic transgene are major hurdles that must be solved to effectively implement this technology. Current gene delivery methods involve substantial tradeoffs between safety, durability, and level of expression. For instance, AAV or plasmid-based systems are generally safe but have limited duration of expression in actively replicating cells. A promising alternative is cleavage with site-specific nucleases to bias insertion into a chosen genomic locus.
INNOVATION:
Researchers at UCLA have investigated the use of nuclease-based integration to allow exact transgene positioning at a minimal risk of gene silencing or activation of nearby oncogenes. Due to the specificity of nuclease activity, the transgene may be inserted into a specific “safe harbor” location in the genome that utilizes either the promoter found at that locus or by an exogenous promoter that is fused to the transgene prior to insertion. Hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene been established as a safe harbor for transgene integration with constitutively low expression and low frequency of random integration. The research team has developed a non-endogenous fusion protein containing a zinc finger protein that binds to the HRPT and a cleavage domain in order to specifically and effectively modify endogenous HRPT gene locus.
POTENTIAL APPLICATIONS:
ADVANTAGES:
DEVELOPMENT-TO-DATE:
Proof of concept established in T-cell, a B-cell, and stem cell.