Non-homologous end joining repair pathway

Non-homologous end joining repair pathway is a repair mechanism that activates in eukaryotic cells when double-strand breaks (DSB) are produced in the DNA. It repairs the DNA without the need of a homologous DNA strand as template, hence its name.

This pathway is very active in the cells, it is normally the first mechanism that activates when a DSB is produced, and it requires less time than other paths. However, around 5% of the repair products contain errors. These errors are normally insertions, deletions, or even frameshifts in the open reading frame, which may lead to the inactivation of the gene. Due to its nature, techniques like CRISPR-Cas9 rely on it to generate knock-out cells