852. Chromatin Study of Adenovirus Vector DNA In Vivo

Top of pageAbstract Recombinant adenoviral vectors are robust at transgene expression in a wide variety of tissues including the liver. While adenoviral- mediated transgene expression can be persistent in the absence of toxicity, very little is know about the structure of the adenoviral genome once it enters the nucleus. Our interest is related to the chromatin structure of both 1st generation and gene-deleted adenoviral vectors in vivo. We have previously established that intact plasmid DNAs that are silenced have a different chromatin structure than minicircle DNAs devoid of bacterial plasmid DNA sequences, which are persistently active in vivo. We hypothesized that upon entering the nucleus, adenoviral DNA will be packaged in cellular histones and form chromatin structures similar to those observed with transcriptionally active plasmid DNAs. By using chromatin immunoprecipitation (CHIP), we have begun comparing the chromatin modifications of adenoviral vector, plasmid, and minicircle DNAs over the course of time after vector administration into mouse liver. Our preliminary results show differences in histone modifications between adenoviral genomes and plasmid DNAs. Further analyses should allow us to determine if histone modifications play a role in transgene expression from episomal vectors in vivo.