The FRT cassette present in the progenitor DroncKO.FRT.Dronc.WT.GFP.APEX2.FRT.Dronc.CAEA.SunTag(Unk),Tag:HA,mCherry allele has been excised, allowing the full-length, enzymatically inactive and proteolytically uncleavable Dronc (with C318A and E352A mutations) tagged with SunTag(Unk), Tag:HA and mCherry at the C-terminus to be expressed under the control of endogenous Dronc regulatory sequences.