Analysis of the size of DNA packaged by the human JC virus-like particle.

Previously, it has been demonstrated that the JC virus-like particle (VLP) is able to package DNA in E. coli and deliver the DNA into human colon cancer cells for gene expression. In this study, the maximum size of DNA packaged by the VLP was determined further. Plasmid DNAs with various sizes were packaged by the VLP in E. coli. Human neuroblastoma cells were then infected with the VLPs containing the various sizes of DNA to allow gene expression. In addition, plasmid DNAs packaged in the VLPs were extracted and retransformed back into E. coli under selection to determine the size of the DNA packaged. The results showed that the JC VLP was able to package plasmid DNA in E. coli up to at least 9.4 kbp in size and this size of DNA could be delivered successfully into human neuroblastoma cells for gene expression. The JC VLP is able to package exogenous DNA up to at least 9.4 kbp in size for gene transduction. These findings will help with the development of gene delivery systems using the JC VLP as the gene delivery vector.