BACTERIAL BETA-GALACTOSIDASE AND HUMAN DYSTROPHIN GENES ARE EXPRESSEDIN MOUSE SKELETAL-MUSCLE FIBERS AFTER BALLISTIC TRANSFECTION

Ballistic transfection, based on cell and tissue bombardment by the tu ngsten and gold microparticles covered with the gene DNA, was used for the delivery of a bacterial beta-galactosidase and a full-length cDNA copy of the human dystrophin genes into mouse skeletal muscles, CMV-l acZ, SV40-lacZ, LTR-lacZneo and full-length cDNA dystrophin (pDMD-1, a pproximately 16 kb) in eukaryotic expression vector pJ OMEGA driven by mouse leukaemia virus promotor (pMLVDy) were used throughout the stud ies. Musculus glutaeus superficialis of C57BL/6J and quadriceps femori s of mdx male mice were opened surgically under anesthesia and bombard ed by means of the gene-gun technique originally developed by us, Diff erent mixtures of gold and tungsten particles at ratios of 4:1, 1:1, 1 :4 were applied, X-gal assay revealed marked beta-gal activity, both i n total muscles and whole muscle fibers ore histological sections, up to three months after transfection, The most intensive staining was ob served after SV40-1acZ delivery, No staining was detected with LTR-lac Zneo DNA as web as in untreated muscles, The higher tungsten particle concentration in the bombardment mixture correlated,vith more intense X-gal staining, At the gold/tungsten ratio of 1:4 the microparticles p enetrated the musculus glutaeus superficialis and transfected the unde rlying musculus glutaeus medius as well, Immuno-cytochemical assay for human dystrophin revealed dystrophin positive myofibers (DPM) in the bombarded area up to two months after transfection, The proportion of DMP varied from 2.5% on day 17 up two 5% on day 60 after bombardment c ompared to only 0.5% in the control mdx mice, These results suggest th e applicability of particle bombardment for gene delivery into muscle fibers. (C) 1997 Federation of European Biochemical Societies.