Researchers from the U.S. and Switzerland recently reported on the potential for nonviral gene therapy using a transposon known as piggyBac. A transposon, or jumping gene, is a sequence of DNA that can move to different positions within the genome of a single cell. Much of gene therapy research has focused on different viral modes of gene delivery. While viruses seem well suited to deliver therapeutic genetic material, they are also effective at entering a host organism’s DNA. A significant drawback in using this therapy has been that it can trigger immune reactions or activate cancer-causing genes. The theoretical advantage of using a piggyBac, in contrast, is that the gene can be delivered safely to a specific location in the genome, where it can achieve the desired therapeutic response. Scientists believe that this type of gene therapy could have multiple applications, including the correction of single gene disorders such as muscular dystrophy and hemophilia.
Researchers have had success using this mode of delivery in insects and foresee other applications. “We can do it in insects,” said Stefan Moisyadi, PhD, one of the scientists collaborating on the project, and an assistant researcher in the Department of Anatomy, Biochemistry and Physiology at the University of Hawaii. “I think it's a short step to take it to a targeting mechanism we can use in mammals.” After comparing it with other transposons, the team concluded that piggyBac is a good candidate because of its receptivity to modification and efficiency in delivering genetic material to the human genome.
“Typically, viruses and transposons will integrate anywhere along the genome," said Joseph Kaminski, MD, a research team member and an assistant professor in radiology at the Medical College of Georgia. “If they integrate just anywhere, it can obviously cause harm. If we can target the integration, be able to insert the gene at a safe spot in the genome, that would be beneficial.”
The study, “piggyBac is a flexible and highly active transposon as compared to Sleeping Beauty, Tol2, and Mos1 in mammalian cells,” was published in the October 10, 2006 issue of the Proceedings of the National Academy of Sciences.
Sources: Ascribe Newswire, October 5, 2006