New looks into DNA editing have led researchers to discover a relatively simple, accurate, and cost-effective way to cut DNA in desired areas to remove faulty genes and replace them with genes that function properly.
Discovered in 2012 by a group of researchers from Howard Hughes Medical Institute, University of California, Berkeley, and the Laboratory for Molecular Infection Medicine – Sweden, the trio published the first paper on their discovery in Science wherein they described a new method of precisely targeting and cutting DNA in bacterial cells.
While the discovery was labeled a “tour de force” in a 2012 review, two additional papers have now been released by other researchers demonstrating this technique’s ability to work in human cells as well. The potentials in gene therapy for this type of technology are endless.
“The ability to modify specific elements of an organism’s genes has been essential to advance our understanding of biology, including human health,” said Doudna, a professor of molecular and cell biology and of chemistry and a Howard Hughes Medical Institute Investigator at UC Berkeley. “However, the techniques for making these modifications in animals and humans have been a huge bottleneck in both research and the development of human therapeutics.”
“I think this is going to be a real hit,” said George Church, professor of genetics at Harvard Medical School and principal author of one of the Science Express papers. “There are going to be a lot of people practicing this method because it is easier and about 100 times more compact than other techniques.”
The impact of this discovery has been likened by Doudna to the significance of the Polymerase Chain Reaction (PCR) which made generating millions of replicates of small pieces of DNA a simple matter and has become a staple technology in the biological research and medical genetics fields.
There has been a lot of media coverage recently on the success of both Zinc-Finger Nucleases (ZFNs) and TALENs (Transcription Activator-Like Effector Nucleases). They have even been referred to as “cruise missiles” in Science magazine’s list of the top ten breakthroughs in 2012 for their ability to hone in on a specific section of DNA and make precise cuts to remove the section of interest and even replace it with an onboard version of the gene. These make for some pretty exciting breakthroughs, and Sangamo Biosciences was even able to replace one gene in an HIV-infected individual to make them AIDS-resistant.
The recently released article even went so far as to compare the ZFN and TALEN technology to the new technique which involves an enzyme called Cas9, and found it five times more efficient for inserting a gene into a mammalian cell. Not only is it more efficient when in use, ZFNs and TALENS both require the synthesis of large new genes encoding a specific protein for each new site in the DNA that is to be changed. Cas9, on the other hand, uses only a single protein that requires a short RNA molecule to program it for site-specific DNA recognition.
“It’s too early to declare total victory” over TALENs and zinc-fingers, Church said, “but it looks promising.”