Fig 1. Tandem repeat assisted genome editing (TRAGE) in comparison with the four reported strategies.

(a) Cre/loxP or Flp/FRT systems. (b) The Pop-in/Pop-out strategy. (c) SceI assisted method. (d) Custom endonucleases assisted gnome editing method. (e) A model for the current understanding of how RecBCD responds to DSBs in front of the replication fork. (f) The model for TRAGE: First, desired DNA fragment with the selectable marker flanked by tandem repeats was introduced into the target site via intermolecular homologous recombination assisted by Red enzymes. Then, seamless excision of the selectable marker was realized via DSB repair based on intramolecular homologous recombination among the tandem repeats. The excision of selection cassette was realized via replication fork reactivation by the mechanism shown in (e)