The CRISPR-Cas9 genome-editing system interferes with a target sequence of DNA, usually with the goal of inhibiting the expression of a gene or modifying its code. The Cas9 enzyme has been adjusted so that it can also activate genes, but the effect is far less robust. Feng Zhang of the Broad Institute and MIT and colleagues have now tweaked Cas9 so that it can upregulate any gene of interest, even those that have resisted previous attempts using CRISPR-Cas.
According to a study published this week (December 10) in Nature, Zhang’s group used structural data of the Cas9 enzyme to re-engineer it to include gene activation complexes in new sites.1 “Here we have shown that the...system is robust, specific, and can facilitate genome-scale gain-of-function screening when combined with a compact pooled [guide RNA] library,” the authors wrote in their report.
“If you use the older generation of tools, getting the technology ...
