Gene puncture repair kit

An all-in-one DNA editing kit capable of repairing genetic mistakes in cells has been developed byscientists in Denmark.

A host of diseases, including cancers, neurological syndromes like Alzheimer's and conditions like cystic fibrosis are caused by genetic spelling mistakes, also known as mutations.

Putting these right could prevent the disease, but "genetic editing" have not previously been possible. The best scientists could do was to add healthy or working copies of genes to cells to make up for a missing or defective gene.

Now, Aarhus University researcher Jacob Giehm Mikkelsen and his colleagues have come up with a molecular-sized puncture repair kit for genes, which can locate and then patch-up damaged DNA. Even more incredibly, they've used a modified AIDS virus to do it.

The viral genetic material has been replaced with a sequence that will work like a repair patch, pasting itself into the cell's DNA to replace a defective gene. At the same time, the researchers have altered the proteins that make up the coat of the virus, tacking onto hundreds of pairs of DNA-sized scissor molecules.

These so-called "zinc-finger nucleases" are purpose-built so that, when they are unleashed inside a cell, they can look for a unique region or sequence of genetic letters in a cell's DNA which they they cut, excising a defective region. In these locations, the DNA-repair patch carried by the virus is then pasted into place.

In tests, the team were able to use the system to fix a faulty gene encoding a glowing protein, which successfully switched on after the virus was added to the cells.

"Our findings," Mikkelsen says, "generate a new platform for genome engineering based on efficient and potentially safer delivery of programmable nucleases."