The Sleeping Beauty tranposon (SB-Tn) system, a gene therapy technology that avoids the pitfalls of transferring genes with viruses, shows promise in laboratory experiments for correcting the gene defect responsible for sickle cell disease (SCD), scientists in Minnesota are reporting.
In the study, Clifford J. Steer and colleagues note that viruses have gotten most attention as possible vectors, or delivery vehicles, for replacing defective genes with normal copies. In SCD, a mutation in the gene that encodes for beta globin results in abnormal hemoglobin that gives red blood cells a sickle shape. Concerns about potential risks and other problems with viral vectors, however, have become barriers to use of gene therapy.
Using laboratory cell cultures, the researchers showed that SB-Tn system could transfer normal beta globin genes into cells. The system, named for a fish gene reawakened by other researchers in 1997 after 15 million years of dormancy, fulfills essential requirements for gene therapy, the report states. Cells take up genes transferred with SB-Tn technology, the genes produce beta globin in stable fashion for long periods, and the genes are inherited and passed along as cells reproduce. Scientists term Sleeping Beauty as a transposon, or a “jumping gene” because it can jump from one location on a piece of DNA to another.