Gene therapy -- the insertion of new genes -- offers exciting possibilities for treatment of both genetic and non-genetic diseases. But among the challenges remaining is a method for regulating how much protein is produced from a gene at any given time.
Normally, our cells "decide" how much of a protein to make from the gene, or "recipe" for that protein. However, when we introduce a gene into a cell artificially, through gene therapy, the gene isn't hooked up to the cell's normal control system. Doctors would like to have a way to regulate the amount of protein made from artificially inserted genes.
MDA grantee James Wilson, who heads the Institute for Human Gene Therapy at the University of Pennsylvania in Philadelphia, was on a team that's developed a method for a drug-responsive control system that they say will work in at least some forms of gene therapy. In the system that the researchers developed and tested in animals, the gene for a blood-cell-forming protein (erythropoietin) was injected with two other genes that "turn on" erythropoietin production in the presence of the drug rapamycin. When the animal takes rapamycin by mouth, the gene is turned on by the molecular switch. Without rapamycin, the gene shuts off, and no erythropoietin is made.
Wilson's team developed the rapamycin gene switch in conjunction with scientists at Ariad Pharmaceuticals of Cambridge, Mass. The rapamycin study is in the Jan. 1 issue of Science.
