Vol. 186, No. 3,1992 August 14, 1992 BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Pages 1417-1422 INTERACTION OF DNA WITH CATIONIC LIPOSOMES: ABILITY OF TRANSFECTING LENTIL PROTOPLASTS Mauro Maccarrone, Luciana Dini§, Luisa Di Marzio°, Antonio Di Giulio+, Antonello Rossi, Giuseppe Mossa° and Alessandro Finazzi-Agr6* Dipartimenti di Medicina Sperimentale e Scienze Biochimiche e di §Biologia, Universit~ di Roma "Tor Vergata", Rome, Italy °Istituto di Medicina Sperimentale del C.N.R., Rome, Italy +Dipartimento di Scienze e Tecnologie Biomediche e Biometria, Universit~ di L'Aquila, L'Aquila, Italy Received June 17, 1992 Summary: The vesicles made of dipalmitoylphosphatidylcholine and stearylamine (9:1) were multilamellar and rather homogeneous in shape as seen by transmission electron microscopy. Upon addition of circular DNA plasmids of different lengths to the liposomes, the formation of vesicle clusters around the DNA filament was observed, with dimensions dictated by the ratio DNA/lipid. These liposomes were able to transfect lentil (Lens culinaris) protoplasts inside the cells two different reporter genes, chloramphenicol-acetyltransferase and I$-glucuronidase. The activity of these two enzymes could be found in the cell lysates after 24 h from the incubation of protoplasts with the lipid-DNA complexes. ~ 1992 AcademicP ..... Inc. A wide variety of methods have been developed so far to overcome the permeability barrier imposed by the cell membrane, thus facilitating the introduction of exogenous genes into eukaryotic ceils (transfection). Some introduced DNA can reach the nucleus, leading to transient or stable expression of the relative gene. The current transfection methods include the use of polycations (1), fusogenic polymers (2), microinjection (3), electroporation (4), biolistics (5) and laser microbeam (6). Because of their ability to fuse directly with the plasma membrane or to be taken up by cells via an endocytosis-like process, liposomes have been used in the last few years as tools for transfecting mammalian cells (7) and plant protoplasts (8). In particular, the effective * To whom correspondence should be addressed at Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Universit~ di Roma "Tor Vergata", via O. Raimondo, 00173 Roma, Italia. FAX : +6/7234793. Abbreviations: CAT, chloramphenicol-acetyltransferase; DPPC, L-¢x-dipalmitoyl- phosphatidylcholine; GUS, ]3-glucuronidase; LPs, Lentil protoplasts; REV, reverse-phase evaporation; SA, stearylamine. 1417 0006-291X/92 $4.00 Copyright © 1992 by Academic Press, Inc. All rights of reproduction in any form reserved.