New Peptides
For Efficient Gene Transfer

DNA binding peptides comprised of short peptide loops fused to a DNA binding sequence of 16 lysines (K16) were complexed to plasmid DNA and their in vitro transfection efficiency was studied. The arbitrary cyclic peptides K16-cKYP, K16-cRAD and the linear RGD peptide K16-ARGDA were very efficient in transfection on ECV 304 endothelial cells (order of 10 8 -10 9 RLU/mg protein) suggesting a use of the peptides as transfection agents. Concerning the transfection mechanism results indicate nonspecific endocytosis or phagocytosis.
Efficient introduction of foreign genes into mammalian cells (transfection) is one of the basic steps in the development of DNA delivery procedures for gene therapy. Although viral vectors are the most efficient gene transfer vehicles up to now, nonviral systems such as liposomes and polycations have also been successfully used [for rev. see 1]. Polylysine was conjugated to either peptides, proteins or carbohydrates as recognition signals for cell surface receptors. These modified polylysines complexed to DNA were used to selectively target certain mammalian cells [25]. The polylysine moiety binds, condenses and protects the DNA.