Expression of the human CFTR gene from episomal oriP-EBNA1-YACs in mouse cells

Plasmids carrying the origin of plasmid replication (oriP) and expressing the EBNA-1 protein from the Epstein–Barr virus replicate and segregate in human cells and are thus potentially useful vectors for gene therapy. As very large circular molecules, up to 660 kb in size, can be maintained episomally using this system, it is possible to include intact human genes with all their long-range controlling elements which might give high levels of...