Adenosine Deaminase (ADA) Deficiency is an inherited disorder resulting in immunodeficiency.
Currently, gene therapy for ADA Deficiency is performed using retroviral or lentiviral vectors
that pose a risk of insertional oncogenesis. In this project, an alternative, potentially safer
approach for correcting ADA deficiency was investigated. This approach uses site-specific zinc
finger nucleases (ZFNs) to achieve genome editing. In this study, various aspects of using ZFNs
at the ADA locus in human hematopoietic cells were investigated. To ensure efficient delivery of
ZFNs and donor templates, Integrase-Defective Lentiviral Vectors (IDLVs) were used. The
vector design of IDLVs was optimized. The use of Histone Deacetylase Inhibitors was tested in
conjunction with IDLVs to enhance their efficiency further. In addition, small molecule
inhibitors of DNA-dependent protein kinase (DNA-PK) were tested for their ability to increase
the efficiency of gene modification. These studies provide novel findings that are potentially
applicable to the entire genome modification field and will benefit current and future work on
similar approaches.