Efficient introduction of a gene into hematopoietic cells in S-phase by electroporation.

Cells of the hematopoietic cell line K562 were synchronized by three different methods. The synchronized cells were transfected wia electroporation with plasmid pMoZtk, which contains the beta-galactosidase gene, using a square wave pulse immediately after synchronization or at various time points during culture. Simultaneously, synchronized cells were fluorescence-activated cell sorter (FACS) analyzed to determine their stage in the cell cycle using double staining with bromodeoxyuridine (BrdU) and propidium iodide