An engineered endonuclease enzyme that is used in genome editing to make targeted cuts in both strands of a DNA molecule. It consists of a short chain of zinc finger modules, which recognize and bind to specific base sequences in the target DNA, coupled to a DNA-cleaving domain. The double-strand breaks stimulate the cell’s own DNA repair mechanisms so that strands are rejoined following, e.g. insertion of a new stretch of DNA or deletion of an existing segment.