Biologists create more precise molecular scissors for genome editing

Abstract

By tweaking an enzyme that cuts DNA, synthetic biologists say that they can make genome editing even more specific — an essential improvement if the technique is to be deployed in the clinic to treat genetic diseases. The enzyme, called Cas9, is a key component of a molecular-editing system that enables researchers to alter particular DNA sequences in the genome. That technology, called CRISPR-Cas9, is so quick, cheap and easy to use that it is already changing how genetic research is done and could one day provide a way to correct genetic mutations that cause disease in humans. On 1 December, researchers from the United States, the United Kingdom and China are convening in Washington DC to discuss the ethics and applications of gene-editing in humans. But before any clinical applications, patients and regulators must be sure that the Cas9 enzyme will not cause dangerous off-target damage to the genome. “For therapeutic applications, we all want to proceed with maximum caution to make sure we’re not modifying the genome at undesired locations,” says David Liu, a chemical biologist at Harvard University in Cambridge, Massachusetts.