Power of Light

The system known as CRISPR has utterly revolutionized gene editing, allowing scientists to manipulate genes in an unprecedented way. Thanks to this genome-editing system, researchers have been coming out with new approaches paving the way towards altering DNA with unprecedented precision and accuracy.

Now, another team of researchers have developed a new technique that offers precise manipulation of when and where genes are targeted, by using the power of light.

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Altering Cas9 Enzyme

As MIT News explains, CRISPR relies on a gene-editing complex composed of Cas9, a DNA-cutting enzyme, and a short RNA strand that directs that enzyme to a specific area of the genome. Previously, researchers altered the Cas9 enzyme so that it will only start cutting when it’s exposed to certain wavelengths of light.

MIT's approach is a little more forward thinking. Instead of programming the Cas9 to be light sensitive, the RNA would be. Thus, it'd be easier to "deliver these modified RNA guide strands than to program the target cells to produce light-sensitive Cas9," says Sangeeta Bhatia, senior author of the paper. To do this, the team created “protectors” consisting of DNA sequences with light-cleavable bonds along their backbones. These DNA strands can be tailored to bind to different RNA guide sequences, forming a complex that prevents the guide strand from attaching to its target in the genome.

The study, published in the journal Angewandte Chemie, resulted in a system that is responsive to ultraviolet light. And this, in turn, may help scientists study the timing of cellular events in greater detail—potentially offering a more targeted way to turn off cancer-causing genes in tumor cells in the future. “The advantage of adding switches of any kind is to give precise control over activation in space or time,” said Bhatia.

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