Disease is on the run! An incredible advance in the realm of gene therapy has been made by top researchers in the US and Sweden. A single enzyme from a bacteria’s immune system can effectively be used to locate specific sections of DNA in a living cell. From there, entire genes can be neutralized or replaced with superior sections of DNA. Clearly, we are on the brink of gene therapy becoming a common and highly effective treatment for terrible diseases like AIDS and cancer.

A group of researchers from MIT, the Broad Institute, and Rockefeller University have been able to use bacterial protein-RNA systems to find and disrupt the DNA of a virus. Cas9, an enzyme that can break the bond in nucleotide subunits of the nucleic acids, is used to target specific parts of a genome. When it finds a match, the Cas9 effectively cuts that segment of DNA. From there, it either leaves the gene non-functional, or allows the researchers to insert replacement DNA into the genome. Impressively, this method is highly precise. Unlike previous attempts at snipping out chunks of DNA, this method will only activate if the DNA segment is an exact match.

Meanwhile, researchers at the Howard Hughes Medical Institute, UC Berkeley, and Emmanuelle Charpentier of the Laboratory for Molecular Infection Medicine have published two papers in Science Express explaining their research on the Cas9 enzyme. Harvard Professor George Church explains that Cas9 is five times more efficient than the TALEN (Transcription Activator-Like Effector Nucleases) method of gene alteration. While the TALEN and zinc-finger nucleases techniques are useful, they require much more work and are less precise than Cas9. This new method needs only a tiny RNA molecule to be programmed to seek a specific section of DNA.

Once we pinpoint specific genes that cause a disease, Cas9 can be sent in to remove the offending base pairs. Clinical trials using the zinc-finger nucleases method are being performed already, and this breakthrough will provide even more options going forward. Feng Zhang, an MIT assistant professor, believes that this can even be used to study disease by causing mutations in healthy cells. Previously fatal diseases can now be targeted and even potentially cured. Correcting defective genes and stomping out rogue viruses are on the table now, and it’s only a matter of time before gene therapy becomes a common tool like vaccines and antibiotics for physicians.

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Research papers: DOI: 10.1126/science.1232033 – “RNA-Guided Human Genome Engineering via Cas9”; DOI: 10.1126/science.1231143 – “Multiplex Genome Engineering Using CRISPR/Cas Systems”; “RNA-programmed genome editing in human cells” [PDF]

[Image credit: Duncan Hull & Stuart Caie]