Encapsidated adenovirus mini-chromosome-mediated delivery of genes to the retina: application to the rescue of photoreceptor degeneration

Hum Mol Genet. 1998 Nov;7(12):1893-900. doi: 10.1093/hmg/7.12.1893.


First (DeltaE1/E3) and second (DeltaE1+DeltaE2/E3/E4) generation adenovirus (Ad) vectors have been shown previously to be of limited use in the treatment of human genetic diseases due to the induction of a host cytotoxic T-cell mediated immune response against virally expressed genes. In addition, a limited cloning capacity of approximately 8 kb does not cater for the incorporation of large upstream sequences essential for regulated tissue-specific expression or inclusion of multiple gene-expression cassettes. In this study we have exploited our recently developed Ad-based vector, the encapsidated adenovirus mini-chromosome (EAM) from which all of the viral genes have been deleted. EAMs contain only the inverted terminal repeats required for replication and five cis -acting Ad encapsidation signals necessary for packaging. We have shown previously that EAMs can efficiently transduce a variety of cell types in vitro. In this study we demonstrate that EAMs can transduce and rescue cells from the neurosensory retina in vivo. EAM-mediated delivery of the beta subunit of cyclic GMP phosphodiesterase (PDE) cDNA to mice affected with retinal degeneration (rd) allows prolonged transgene expression and rescue of rod photoreceptor cells. RT-PCR analysis from the injected retina indicates that transgene products are present for at least 18 weeks post-injection. Both the alpha and beta subunits of PDE could be detected up to 90 days postnatal in EAM-injected rd retina by western analysis. A maximal PDE activity of 150 nm/min/mg was detected at 33 days postnatal. Examination of outer nuclear thickness showed significant differences up to 12 weeks post-injection. These results demonstrate an improved level of rescue over first-generation adenoviral vectors and suggest the possibility of successful EAM-mediated treatment of some retinal diseases in humans.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenoviridae / genetics*
  • Adenoviridae / ultrastructure
  • Animals
  • Capsid / genetics*
  • Capsid / ultrastructure
  • Cell Line
  • Cloning, Molecular
  • Gene Expression
  • Gene Expression Regulation, Viral
  • Gene Transfer Techniques*
  • Genetic Therapy
  • Genetic Vectors / genetics
  • Genome, Viral*
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Photoreceptor Cells / metabolism
  • Photoreceptor Cells / pathology
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Retina / metabolism*
  • Retina / pathology
  • Retinal Degeneration / genetics
  • Retinal Degeneration / therapy
  • Transfection
  • Transgenes / genetics


  • Recombinant Fusion Proteins