Rationally engineered Cas9 nucleases with improved specificity

TLDR

The CRISPR/Cas system, a prokaryotic immune mechanism that cleaves foreign DNA, has been repurposed for gene editing but faces challenges from off‑target cleavage that could compromise clinical safety. The authors used structure‑guided engineering to create SpCas9 variants with improved specificity. The engineered eSpCas9 variants exhibit reduced off‑target activity while preserving strong on‑target cleavage, as reported in Science. Citation: Slaymaker et al.

Abstract

Making the correct cut The CRISPR/Cas system is a prokaryotic immune system that targets and cuts out foreign DNA in bacteria. It has been adopted for gene editing because it can be designed to recognize and cut specific locations in the genome. A challenge in developing clinical applications is the potential for off-target effects that could result in DNA cleavage at the wrong locations. Slaymaker et al. used structure-guided engineering to improve the specificity of Streptococcus pyogenes Cas9 (SpCas9). They identified enhanced-specificity variants (eSpCas9) that display reduced off-target cleavage while maintaining robust on-target activity Science , this issue p. 84