Expression of human ATM cDNA in Atm-deficient mouse brain mediated by HSV-1 amplicon vector.

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder characterized by neurodegeneration, immunodeficiency, cancer predisposition, genome instability, and radiation sensitivity. Herpes simplex virus type 1 (HSV-1) amplicon vectors provide a means to deliver large genes to the nervous system efficiently and safely. We have generated an amplicon vector, carrying human FLAG-tagged A-T mutated (ATM), as well as an enhanced green fluorescent protein (EGFP) marker gene. Due to the lack of effective and reliable antibodies for ATM and FLAG appropriate for immunohistochemistry in mouse tissue sections, expression of the human FLAG-tagged ATM was confirmed in the mouse cerebellum at the RNA level by reverse transcription followed by quantitative PCR, and by radioactive in situ hybridization. In addition, we were able to immunoprecipitate the full-length human ATM protein from the cerebella of Atm -/- mice post-infection. This vector has been injected into the cerebella of Atm -/- mice with gene delivery to thousands of cells, including Purkinje cells, based on the EGFP marker gene. The expression of human FLAG-tagged ATM has been demonstrated in the cerebella of Atm-/- mice at the transcription and translational level three days post-infection. To our knowledge, this is the first report of vector-mediated delivery of the human ATM cDNA to an Atm -/- mouse. These vectors provide the groundwork to develop gene therapy approaches for A-T patients.