Repair of ZFN-induced breaks commonly occurs via:
Repair of nuclease induced breaks determines editing outcome and is governed by competitive engagement of canonical non-homologous end joining NHEJ and homology-directed repair HDR pathways. NHEJ active throughout cell cycle especially G1, initiated by Ku binding, DNA-PKcs activation, end processing by Artemis and polymerase mu, ligation by Lig4-XRCC4-XLF complex. It is error-prone with indels up to tens of base pairs at cleavage site leading to gene disruption valuable for knockout breeding. Alternative microhomology mediated end joining using Pol theta also produces deletions. HDR pathway re
Ref: Ceccaldi et al. Nat Rev Genet 2016 17:147 NHEJ HDR; Symington Lenski Annu Rev Genet; Alberts.
