title: Loosening of DNA/polycation complexes by synthetic polyampholyte to improve the transcription efficiency: effect of charge balance in the polyampholyte.
abstract: High mobililty group proteins are amphoteric nuclear proteins that are known to unfold chromatin to stimulate transcription. To mimic their structures, we synthesized the novel polyethylene glycol (PEG) derivatives, PEG-ACs, consisting of both amino- and carboxyl-pendants in various ratios, and their loosening and transcription-improving activity on the DNA complex was examined. Fluorescence anisotropy measurement revealed that anionic PEG-ACs with more carboxyls than amines could efficiently loosen the DNA/polyethyleneimine complex. Those anionic PEG-ACs showing a loosening effect on the DNA complex evidently increased the transcription rate to >20 times higher than that of the original complex, probably owing to the facilitated approach of transcriptional factors to the DNA segments in the loosened complexes. The complexes with anionic PEG-ACs also showed improved transgene expression level on the cultured cells, indicating the effectiveness of improving transcriptional activity to attain a high extragene expression by the plasmid complex. The loosening mechanism of DNA/polycation complexes was investigated with a simplified model via Monte Carlo simulation to discern the difference in the presence of cationic polyampholytes, anionic polyampholytes, and polyanions.
authors.affiliation: Otsuma Women's University Graduate School, Sanbancho, Chiyoda-ku, Tokyo, Japan.
authors.forename: Chieko
authors.initials: C
authors.lastname: Yoshihara
authors.forename: Chwen-Yang
authors.initials: CY
authors.lastname: Shew
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ito
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Koyama
mesh_terms: D000838:Anions; D016880:Anisotropy; D001703:Biophysics / Q000379:methods*; D002412:Cations; D004247:DNA / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D008957:Models, Genetic; D009010:Monte Carlo Method; D010957:Plasmids / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry*; D011401:Promoter Regions, Genetic; D013050:Spectrometry, Fluorescence / Q000379:methods; D055672:Static Electricity; D014158:Transcription, Genetic; D019076:Transgenes
chemical_list: D000838:Anions; D002412:Cations; D011092:Polyethylene Glycols; D004247:DNA