Figure 7 .

: Detection of plasmid DNA in tissue samples after gene transfer. Three days after injection of oesophageal segments with RSV-LacZ DNA-liposomes genomic DNA was isolated. Genomic DNA (1 µg) was subjected to PCR analysis; 1 ng RSV-LacZ or 293 cells transfected with 5 µg RSV-LacZ were used as positive controls. One tenth of the PCR reaction was electrophoresed on a 1.6% agarose gel, stained with ethidium bromide, and photographed. Recombinant RSV-LacZ DNA was not detected as a specific 318 bp band in all tissues except in the oesophagus (A). Positive and negative controls are shown along with DNA markers. To enhance the signal Southern blot analysis was performed (B). The gel was blotted onto nitrocellulose and hybridised to a LacZ specific probe. No signals were detected in the negative control or in any tissue except the oesophagus.