CRISPR-Cas tagged posts

The Cas13a enzyme causes collateral RNA damage that is the heart of a new diagnostic system, SHERLOCK, that can detect minute quantities of virus and much more

Researchers have created a version of CRISPR-Cas that can be used to diagnose infections, such as Zika and dengue, with a high level of sensitivity. The advancement could help facilitate rapid detection and diagnosis of many other pathogens, too. While some methods exist for detecting genetic sequences, they have trade-offs among sensitivity, specificity, simplicity, cost, and speed. In the search for a more effective method, Feng Zhang, Jonathan S. Gootenberg and colleagues turned to a CRISPR-Cas system that targets RNA.

Binding the target RNA activates this particular Cas enzyme to promiscuously cleave nearby RNA...

This image shows how the CRISPR surveillance complex is disabled by two copies of anti-CRISPR protein AcrF1 (red) and one AcrF2 (light green). These anti-CRISPRs block access to the CRISPR RNA (green tube) preventing the surveillance complex from scanning and targeting invading viral DNA for destruction. Credit: Image from Lander Lab/The Scripps Research Institute

Scientists now reveal how viruses disable bacterial immune systems. For many bacteria, one line of defense against viral infection is a sophisticated RNA-guided “immune system” called CRISPR-Cas. At the center of this system is a surveillance complex that recognizes viral DNA and triggers its destruction...