Scientists have invented a method of compressing DNA which could make gene therapy powerful. The advance which is now being tried out on cystic fibrosis patients, may allow the modified genes to slip right into the cell nucleus.A single strand of DNA contains a complete blueprint for building an entire human.
This means that the DNA molecule is long and unwieldy. Doctors are looking for ways to smuggle or slip their modified DNA strands into the cells they want to change.
Other methods involve using viruses - which "infect" the cell and pass on the new genes that way, or encasing the DNA in fatty globules called liposomes, which are pulled into the cell by a natural process.
However, infecting patients with viruses carries its own risks, and liposome production is less efficient. The new technique involves taking the long strands of DNA and "scrunching" them up into a more compact package.
This tiny ball, 25 nanometres across - 25 millionths of a millimetre - is much smaller than a liposome, and should be able to pass into the nucleus of a cell through pores in its surface, say the scientists. In cells in a test tube, the tiny DNA packets appeared to be as much as 6,000 times more effective at getting their genes working in the nuclei of cells than DNA-carrying liposomes.
Now basic safety trials have begun involving human patients, suffering from cystic fibrosis also. This disorder, which involves faulty production of the mucus which lines the lungs, is caused by a single faulty gene.