Related Experiment Video
Updated: Aug 12, 2026

Direct Protein Delivery to Mammalian Cells Using Cell-permeable Cys2-His2 Zinc-finger Domains
Published on: March 25, 2015
Membrane-permeant, DNA-binding agents alter intracellular trafficking and increase the transfection efficiency of
Sylvia Fong1, Yong Liu, Timothy Heath
1California Pacific Medical Center Research Institute, San Francisco, CA 94115, USA.
Abstract:
Nuclear delivery of extracellular DNA by nonviral vectors is inhibited by a series of cell membrane and compartmental barriers. Certain cationic amphiphiles that partition through cellular membranes to bind genomic DNA can enhance nuclear delivery of plasmid DNA. Specifically, delivering plasmid DNA complexed to the DNA-binding dye Hoechst 33258 produces cellular transfection levels similar to those achieved by cationic liposome:DNA complexes (CLDC), with less toxicity. Incorporating Hoechst into CLDC or polyethyleneimine:DNA complexes significantly increased reporter gene expression, as well as the percentage of cells transfected. Hoechst:CLDC significantly improved transfection of nondividing cells and efficiently transfected cells in the presence of anionic molecules that block cellular uptake of and transfection by CLDC alone. Hoechst:CLDC also increased gene expression in mouse tissues following intravenous delivery. Delivery of fluorescently labeled plasmid DNA via Hoechst altered its intracellular trafficking by both minimizing lysosomal sequestration and accelerating delivery into the nucleus. Agents such as Hoechst constitute a novel class of nonviral carriers that can confer their membrane-permeant properties on complexed DNA, thus redirecting its intracellular trafficking. In addition, binding of Hoechst 33258 to specific chromosomal DNA target sequences and its ability to modulate transcription may further enhance the expression of delivered genes.
Related Concept Videos
Bacterial Transformation
DNA-only Transposons
The donor site from where the transposon is excised is either degraded or...
Detergent Purification of Membrane Proteins
Protein Diffusion in the Membrane
Mechanisms of Membrane Domain Formation
Another mechanism for membrane domain formation involves membrane proteins interacting with cytoskeletal...
Transformation

