Gene therapy can potentially cure many hereditary and acquired diseases, such as cancer, hemophilia and cystic fibrosis, by delivering a healthy copy of a gene to the cells that need it. Researchers have been working on ways to deliver genes safely and effectively to the right locations. One promising approach is to use negatively charged lipids that reside in cell membranes of mammals. The idea is to pack a gene, made of DNA, into a lipid pocket, which then fuses with a cell membrane and empties the gene into the cell. The advantage of these anionic lipids (AL) is they do not evoke an immune response. The disadvantage is they do not attach well to DNA because both are negatively charged.

Researchers from the University of Illinois at Urbana-Champaign and the National Institutes of Health used x-ray techniques at BL4-2 at Stanford Synchrotron Radiation Laboratory and at the Advanced Photon Source at Argonne to investigate how to stick AL and DNA together. They made AL-DNA complexes using different kinds of positively charged ions to act as the glue. DNA could be packed into or expelled from a lipid pocket depending on the concentrations of the ions being used and the density of negative charge on the lipid. The researchers found that these different AL-DNA structures can be understood in terms of a simple theoretical model, which can serve as a recipe book for the design of the next generation of gene delivery agents.

To learn more about this research see the full scientific highlight at:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/AL-DNA.html

Liang, H.J., Harries, D. & Wong, G.C.L. Proc. Natl. Acad. Sci. USA 102, 11173-11178. (2005)