Helper-dependent adenoviral vectors in the treatment of citrullinemia

Document Type

Conference Paper


Emergency Medicine


Citrullinemia is a urea cycle disorder characterized by deficiency of argininosuccinate synthetase (ASS). Gene therapy correction in both humans and animal models will require high levels of hepatocyte transduction and long-term transgene expression. To achieve these objectives, we have generated helper-dependent adenoviral vectors devoid of viral coding genes which express human ASS (hASS) from a ubiquitously active elongation factor 1 (BOS) promoter (Ad?BOShASS). Evaluation of Ad?BOShASS by Southern analysis, real-time quantitative PCR, and fluorescent in situ hybridization (FISH) after intravenous injection into C57BL/6 mice show helper virus contamination of ˂ 1%, stable vector structure, and efficient hepatocyte transduction. Northern analysis using a transgene-specific probe showed mRNA expression levels in liver comparable to wild type murine ASS. Our previous data suggested that use of liver-specific and endogenous genomic promoters may increase transgene expression and blunt the host immune response. We analysed mice at 3 days and 8 weeks after injection with first generation adenoviral vectors expressing hASS from either the ubiquitously expressing CAG promoter or the liver-specific albumin promoter. hASS mRNA expression persisted in mice treated with the albumin promoter vector compared to the CAG promoter virus. These data have prompted us to evaluate helper-dependent vectors containing the endogenous ASS and alpha-1-antitrypsin promoters driving human ASS minigenes for treatment of bovine and human citrullinemia.


This work was published before the author joined Aga Khan University.

Publication (Name of Journal)

Journal of Inherited Metabolic Disease