Writing in the May 20 issue of Nature, the scientists say their artificial jumping gene sets the stage for creating mice that lack -- at random -- at least one gene, without having to know in advance which gene is being "knocked-out." Such random knock-outs have been critical in studying genetics of other critters and will help shed light on jumping genes' effects -- past and present -- in human health and disease, say the researchers.
"Making this synthetic jumping gene was the home-run experiment we never thought was going to work," says Jef Boeke, Ph.D., professor of molecular biology and genetics and director of the High Throughput Biology Center in Hopkins' Institute for Basic Biomedical Sciences.
Jumping genes, aka retrotransposons, are bits of genetic material that copy themselves and move around in creatures' genomes. They have the potential to disrupt the genes they "land" in and are thought to contribute to the gradual --and perhaps the occasional major -- genetic shifts that drive evolution. While organisms like yeast have just a few dozen jumping genes in their genomes, mammals' genomes contain hundreds of thousands of copies of their jumping genes' DNA, making it difficult to know where or when -- or even if -- a jump has happened.
In a second paper in the same issue of Nature, M.D./Ph.D. candidate Jeffrey Han and Boeke report that the human jumping gene is relatively lethargic because its instructions are hard for cells to read. By replacing some of the gene's instructions with alternatives cells prefer, the researchers made the first highly active, artificial jumping gene that is potentially efficient enough to use in mice.
By inserting the artificial jumping gene into cells of a mouse embryo, scientists should be able to develop
Contact: Joanna Downer
Johns Hopkins Medical Institutions