Revamped repair

A University of California Berkeley team has discovered how to boost the efficiency of homology-directed repair (HDR) of genomic cuts made by CRISPR-Cas9, without disrupting proliferation or other DNA repair mechanisms. By dialing in the right rules, the team has produced a method that could make correcting rather than just cutting genes in human cells a reality.

HDR and non-homologous end joining (NHEJ) are genome repair processes that fix double-stranded breaks in DNA caused by factors such as exposure to ultraviolet radiation or damage from reactive oxygen species (ROS). While both mechanisms could, in principle, mend cuts made by CRISPR-associated protein 9 (Cas9), cells tend to favor "error-prone" NHEJ over "error-free" HDR. ...