| May 08, 2015 |
Altering genes with the aid of light |
| (Nanowerk News) Scientists have been manipulating genes for a while. The University of Pittsburgh's Alexander Deiters just found a way to control the process with higher precision. |
| By using light. |
| Deiters and his group are the first to achieve this. The resulting paper was recently published in the Journal of the American Chemical Society ("Optical Control of CRISPR/Cas9 Gene Editing"). |
| Since 2013, scientists have used a gene-editing tool called CRISPR/Cas9. The method employs a bacterially derived protein (Cas9) and a synthetic guide RNA to induce a double-strand break at a specific location in the genome. This enables excision of a gene, alteration of its function, or introduction of desired mutations. |
| In practice, the CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats of DNA base sequences) method has shown tremendous promise to enable researchers to treat cystic fibrosis and sickle-cell anemia, create laboratory animals that mimic human disease, and create a strain of wheat resistant to powdery mildew. |
| Deiters, professor of chemistry in Pitt's Kenneth P. Dietrich School of Arts and Sciences, along with colleagues at the University of North Carolina at Chapel Hill, have, through a series of experiments, found a lysine residue (lysine is an amino acid) in Cas9 that can be replaced with a light-activated analog. |
| The approach developed by Deiters generates a Cas9 protein that is functionally inactive, so called "caged," until the cage is removed through light exposure, activating the enzyme and thereby activating gene editing. |
| "This method may allow people to engineer genes in cells or animals with better spatial and temporal control than ever before," Deiters says. "Previously, if you wanted to knock out a gene, you had limited control over where and when it would happen. Engineering a light switch into Cas9 provides a more precise editing tool. You can say, 'In this cell, at this time point, is where I want to modify the genome.'" |
| The improved control over the time and location at which a gene will be manipulated, Deiters says, may help eliminate "off-target effects" and could potentially enable genetic studies with unprecedented resolution. |
| Source: University of Pittsburgh |
