P{hs-yB.Q486E.P501T} expresses the same zinc finger nuclease encoded by P{hs-yB} (FBtp0016057) except for substitution of sequences encoding Threonine for Proline at residue 501 and Glutamic acid for Glutamine for at residue 486. As above, the P501T substitution corrects a missense mutation to give the wild type FokI sequence. The Q486E substitution prevents homodimerization of the zinc finger nuclease. The construct was generated in a Casper-based vector.