In vivo observation of large foreign DNA molecules in host plant cells

We have developed a system to monitor microscopically the fate of foreign DNA within plant cells in vivo. Fluorescein-11-dUTP was used to label DNA during target-specific amplification by polymerase chain reaction (PCR). Labeled DNA fragments of 1.5-3.5 kb were prepared and then transported into tobacco protoplasts by polyethylene glycol (PEG)-mediated direct gene transfer. We localized the foreign, labeled DNA within the cell by confocal laser scanning microscopy.