Main content area

Block Copolymer/Plasmid DNA Micelles Postmodified with Functional Peptides via Thiol–Maleimide Conjugation for Efficient Gene Delivery into Plants

Miyamoto, Takaaki, Tsuchiya, Kousuke, Numata, Keiji
Biomacromolecules 2018 v.20 no.2 pp. 653-661
DNA-binding domains, biotechnology, composite polymers, electrostatic interactions, gene transfer, genes, lysine, micelles, nuclear localization signals, peptides, plasmids
Introducing exogenous genes into plant cells is essential for a wide range of applications in agriculture and plant biotechnology fields. Cationic peptide carriers with cell-penetrating and DNA-binding domains successfully deliver exogenous genes into plants. However, their cell-penetrating activity may be attenuated by undesired electrostatic interactions between the cell-penetrating peptide (CPP) domain and DNA cargo, resulting in limited gene delivery efficiency. Here, we developed the block copolymer maleimide-conjugated tetra(ethylene glycol) and poly(l-lysine) (MAL-TEG-PLL). Through electrostatic interactions with plasmid DNA (pDNA), MAL-TEG-PLL formed a micelle that presented maleimide groups on its surface. The micelle enabled postmodification with cysteine-containing functional peptides, including a CPP (BP100-Cys) and nuclear localization signal (Cys-NLS) via thiol–maleimide conjugation, thereby avoiding undesired interactions. According to a comparison of gene delivery efficiencies among the peptide-postmodified micelles, the amount of BP100-Cys on the micelle surface was key for efficient gene delivery. The BP100-postmodified micelle showed more efficient delivery compared with that of the BP100-premodified micelle. Thus, postmodification of polymeric micelles with functional peptides opens the door to designing highly efficient plant gene delivery systems.