News Release

Student creating polymers to chaperon DNA across cell membrane

Peer-Reviewed Publication

Virginia Tech

Ordinarily, the cell membrane prevents invasion by foreign genetic material, which is why genetic engineers often have to use a pipette and forced air to jab a new piece of a gene through the cell wall into the genome in order to carry out gene therapy or introduce particular attributes into a crop or organism.

But an undergraduate student at Virginia Tech has figured out how to chaperone DNA across cell membranes. Amanda Rudisin of Lucinda, Pa., a senior in biology, will present her team's research at the 227th annual meeting of the American Chemical Society in Anaheim, Calif., March 28 through April 1, 2004.

Rudisin's research looked at linear versus branched molecules in terms of chaperone ability, explains Timothy Long of Blacksburg, professor of chemistry in the College of Science at Virginia Tech. "The poster presents findings regarding the effects of polymer structures on complexation with DNA. Amanda has explored a novel way to transport DNA across cell membranes," says Long. "She looks at the effect of the chemical structure of a gene transfer agent in a very fundamental way. The agent is a polymer that adheres to DNA and will cross the cell membrane."

The poster, "Effects of topology upon transfection efficiency: Synthesis, characterization, and transfection of poly-2-(dimethylamino)ethyl methacrylate and poly-2-(dimethylamino)ethyl methacrylate-co-polyethylene glycol-dimethacrylate (Poly 432)," will be presented 6 to 8 p.m. Tuesday, March 30, in the Anaheim Convention Center Hall A as part of the Division of Polymer Chemistry's program on Biomacromolecule Interactions with Synthetic Surfaces. Co-authors are Rudisin, three Virginia Tech professors, Willard H. Eyestone in the Department of Large Animal Clinical Sciences, William R. Huckle in the Department of Biomedical Science, and Long. Eyestone and Huckle are in the Virginia-Maryland Regional College of Veterinary Medicine.

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Abstract:
Gene transfer agents are under investigation for the delivery of genetic material into cells to produce higher transfection efficiencies. Cationic polymers, a type of gene transfer agent, have the ability to bind to DNA through electrostatic interactions to form polymer-plasmid complexes (polyplexes). Through this electrostatic interaction, masking of the negatively charged phosphate backbone of DNA achieves condensation of plasmid size thus yielding a greater probability of successful transfection across cellular membranes. The water soluble cationic polymers of linear poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and branched PDMAEMA, a copolymer of PDMAEMA and polyethylene glycol dimethacrylate (PEG-dimethacrylate), were synthesized, characterized, and transfected. Linear PDMAEMA, complexed to the plasmid pCMVnt-lacZ (encoding gene for the enzyme Beta-galactosidase), was successfully transfected into both primary (BFF2) and immortalized (COS-7) cell lines. Branched PDMAEMA complexed to pCMVnt-lacZ, at varying polymer to plasmid (w/w) ratios, was successfully transfected into immortalized cells with low qualitative efficiency.

Contact for additional information:
Tim Long, telong@vt.edu, (540) 231-2480
Will Eyestone, weyest@vt.edu, (540) 231-4834
Amanda Rudisin, arudisin@vt.edu


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