title: Effect of chemical features and stability of polyplexes on their gene transfer efficiency.
abstract: Chemically modified poly-L-lysine (PL) derivatives with two essential features, which we have recently reported on, have been used to study key factors affecting transgene expression efficiency. PL derivatives having both of N epsilon-trimethyl lysine residue and 25 mole % serine residue showed enhanced transfection efficiency. When PL was modified in either way, no marked enhancement in gene expression was observed. These PL derivatives were found to be able to deliver plasmid DNA into nucleus of the transfected cells with a similar amount. Judging from the loss of EtBr fluorescence intercalating to DNA, the condensing tendency of the DNA were greatly affected by the sequence of the polypeptides used. This loose compaction seems to enhance the transgene expression because of an easy disassembly of the formed complexes or recognition of the DNA molecules in the complexes.
authors.affiliation: Department of Polymer Science and Technology, Kyoto Institute of Technology, Matsugasaki Sakyo-ku, Kyoto 606-8585, Japan.
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Yamaoka
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kimura
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kitagawa
authors.forename: Reiko
authors.initials: R
authors.lastname: Iwase
authors.forename: Akira
authors.initials: A
authors.lastname: Murakami
mesh_terms: D005453:Fluorescence; D018014:Gene Transfer Techniques / Q000592:standards*; D011107:Polylysine / Q000737:chemistry*
chemical_list: D011107:Polylysine