Abstract
Neumann and coworkers (Neumann, E., M. Schaefer-Ridder, Y. Wang, and P. H. Hofschneider. 1982. EMBO J. 1:841-845) have shown that the efficiency of pulsed electric field (PEF)-induced DNA transfection of mouse L-cells by the thymidine kinase gene is several times higher for the linear DNA than for the closed circular DNA. Transfection of Escherichia coli bacteria by several plasmids indicates that the transfection efficiency was much higher for the closed circular/supercoiled (sc-) and circular/relaxed (cr-) DNA than for the linearized (In-) DNA (Xie, T. D., L. Sun, H. G. Zhao, J. A. Fuchs, and T. Y. Tsong. 1992. Biophys. J. 63:1026-1031). To resolve these conflicting observations, we have systematically examined electrotransfection of NIH3T3 mouse fibroblast by the plasmids, pRSVcat, pRSVneo, and pRSVgpt. Mg(2+)-facilitated surface binding of DNA before, and DNA uptake by 3T3 cells after treatment with PEF, were monitored by 3H-labeled plasmids. Transfection efficiency was evaluated by both the transient expression of chloramphenicol acetyltransferase (cat) activity 2-3 days after, and the permanent expression of neomycin phosphotransferase (neo) and xanthine-guanine phosphoribosyltransferase (gpt) genes in the transformants 2 weeks after the PEF treatment. Our results indicate that cell surface binding and PEF-induced cell uptake of DNA did not depend on the topology of DNA. However, both the transient and the permanent expression of the plasmids were three to five times more efficient for the cr-DNA and the sc-DNA than for the in-DNA. These results indicate that electrotransfection of cells involves several steps: the cation-dependent binding of DNA to the cell surface, the electric field-driven DNA entry into the cells, the transient expression of DNA, and the integration of DNA into the host chromosomes. For understanding mechanisms of electrotransfection, only the DNA binding to the cell surface and the electric field assisted membrane-crossing of DNA are relevant. Both the expression of the loaded DNA and the DNA integration into the host chromosomes depend more on the properties of the cell and its interactions with a foreign gene. Since these properties and interactions will be similar irrespective of the method chosen to facilitate DNA transfer, they are not relevant for the study of mechanisms of electrotransfection. Our results also support the idea that the PEF-induced cellular uptake of DNA is mainly by the electrophoresis of the surface bound DNA across the plasma membrane.
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- Chernomordik L. V., Sokolov A. V., Budker V. G. Electrostimulated uptake of DNA by liposomes. Biochim Biophys Acta. 1990 May 9;1024(1):179–183. doi: 10.1016/0005-2736(90)90222-a. [DOI] [PubMed] [Google Scholar]
- Gorman C., Padmanabhan R., Howard B. H. High efficiency DNA-mediated transformation of primate cells. Science. 1983 Aug 5;221(4610):551–553. doi: 10.1126/science.6306768. [DOI] [PubMed] [Google Scholar]
- Kinosita K., Jr, Tsong T. T. Hemolysis of human erythrocytes by transient electric field. Proc Natl Acad Sci U S A. 1977 May;74(5):1923–1927. doi: 10.1073/pnas.74.5.1923. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kinosita K., Jr, Tsong T. Y. Formation and resealing of pores of controlled sizes in human erythrocyte membrane. Nature. 1977 Aug 4;268(5619):438–441. doi: 10.1038/268438a0. [DOI] [PubMed] [Google Scholar]
- Klenchin V. A., Sukharev S. I., Serov S. M., Chernomordik L. V., Chizmadzhev YuA Electrically induced DNA uptake by cells is a fast process involving DNA electrophoresis. Biophys J. 1991 Oct;60(4):804–811. doi: 10.1016/S0006-3495(91)82115-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sowers A. E., Lieber M. R. Electropore diameters, lifetimes, numbers, and locations in individual erythrocyte ghosts. FEBS Lett. 1986 Sep 15;205(2):179–184. doi: 10.1016/0014-5793(86)80893-6. [DOI] [PubMed] [Google Scholar]
- Sukharev S. I., Klenchin V. A., Serov S. M., Chernomordik L. V., Chizmadzhev YuA Electroporation and electrophoretic DNA transfer into cells. The effect of DNA interaction with electropores. Biophys J. 1992 Nov;63(5):1320–1327. doi: 10.1016/S0006-3495(92)81709-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tekle E., Astumian R. D., Chock P. B. Electroporation by using bipolar oscillating electric field: an improved method for DNA transfection of NIH 3T3 cells. Proc Natl Acad Sci U S A. 1991 May 15;88(10):4230–4234. doi: 10.1073/pnas.88.10.4230. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tsong T. Y. Electroporation of cell membranes. Biophys J. 1991 Aug;60(2):297–306. doi: 10.1016/S0006-3495(91)82054-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Xie T. D., Sun L., Tsong T. Y. Study of mechanisms of electric field-induced DNA transfection. I. DNA entry by surface binding and diffusion through membrane pores. Biophys J. 1990 Jul;58(1):13–19. doi: 10.1016/S0006-3495(90)82349-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Xie T. D., Sun L., Zhao H. G., Fuchs J. A., Tsong T. Y. Study of mechanisms of electric field-induced DNA transfection. IV. Effects of DNA topology on cell uptake and transfection efficiency. Biophys J. 1992 Oct;63(4):1026–1031. doi: 10.1016/S0006-3495(92)81675-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Xie T. D., Tsong T. Y. Study of mechanisms of electric field-induced DNA transfection. II. Transfection by low-amplitude, low-frequency alternating electric fields. Biophys J. 1990 Oct;58(4):897–903. doi: 10.1016/S0006-3495(90)82434-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Xie T. D., Tsong T. Y. Study of mechanisms of electric field-induced DNA transfection. III. Electric parameters and other conditions for effective transfection. Biophys J. 1992 Jul;63(1):28–34. doi: 10.1016/S0006-3495(92)81580-1. [DOI] [PMC free article] [PubMed] [Google Scholar]

