Direct visualization at the single-cell level of electrically mediated gene delivery.
Electropermeabilization is one of the nonviral methods successfully used to transfer genes into living cells in vitro and in vivo. Although this approach shows promise in the field of gene therapy, very little is known about the basic processes supporting DNA transfer. The present investigation studies this process at the single-cell level by using digitized fluorescence microscopy. Permeabilization is a prerequisite for gene transfer. Its assay by propidium-iodide (PI) penetration shows that it occurs at the sides of the cell membrane facing the two electrodes, whereas fluorescently labeled plasmids only interact with the electropermeabilized side of the cell facing the cathode. The plasmid interaction with the electropermeabilized part of the cell surface results in the formation of localized aggregates. These membrane-associated spots are formed only when pulses with a longer duration than a critical value are applied. These complexes are formed within 1 s after the pulses and cannot be destroyed by pulses of reversed polarities. They remain at the membrane level up to 10 min after pulsing. Although freely accessible to DNA dye (TOTO-1) 1 min after the pulses, they are fully protected when the addition takes place 10 min after. They diffuse in the cytoplasm 30 min after pulses and are present around the nucleus 24 h later.
Golzio
Muriel
M
Institut de Pharmacologie et de Biologie Structurale Centre National de la Recherche Scientifique/Unité Mixte de Recherche-5089, 205, Route de Narbonne, 31077 Toulouse Cedex, France.
Teissie
Justin
J
Rols
Marie-Pierre
MP
D000818:Animals; D001692:Biological Transport; D016466:CHO Cells; D002462:Cell Membrane / Q000502:physiology; D002463:Cell Membrane Permeability; D006224:Cricetinae; D004247:DNA / Q000235:genetics; D004594:Electrophysiology; D018274:Electroporation / Q000379:methods*; D005456:Fluorescent Dyes; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D011994:Recombinant Proteins / Q000378:metabolism; D013844:Thiazoles; D014162:Transfection / Q000379:methods*
D005456:Fluorescent Dyes; D008164:Luminescent Proteins; D011994:Recombinant Proteins; C086329:TOTO-1 thiazole orange dye; D013844:Thiazoles; D049452:Green Fluorescent Proteins; D004247:DNA