HISTONE H2A SIGNIFICANTLY ENHANCES IN-VITRO DNA TRANSFECTION

Background: Gene transfer is a potential treatment modality of genetic disease. Efficient, practical methods of DNA transfection are current ly under investigation. Materials and Methods: A beta-galactosidase re porter plasmid interacted electrostatically, with histones, poly-L-Lys , poly-L-Arg, and a combination of poly-L-Lys and poly-L-Arg. This com plex was then used to transfect COS-7 cells. beta-galactosidase activi ty was quantified and used to compare the efficiency of gene transfect ion in vitro. A comparison was also made of DNA transfection with the most active histone subclass, i.e., histone H2A, in the absence and pr esence of an anionic liposome. Results: There was a marked increase in DNA transfection in the presence of histone H2A when compared with th e control, whereas each of the other histones and polycations showed l ittle, if any, effect. The extent of activation depends strongly on th e DNA/histone ratio and is also a function of the molarity of the fina l Tris-acetate, pH 8, solution, The anionic liposomes used demonstrate d an inhibitory effect. Conclusions: Histone H2A significantly enhance s in vitro DNA transfection whereas other histones and anionic liposom es do not. A study of the difference between histone H2A and other his tone subclasses may serve to clarify some of the mechanisms and the es sential components of efficient gene delivery.