A 'Modular vector' (MV) regulatory cassette is fused upstream of a wild-type Drice cDNA that is tagged at the C-terminal end of the coding sequence with Tag:FLAG and with N-Venus. The MV cassette consists of an mFRT71 cassette containing 5xlexAop regulatory sequences plus a minimal Hsp70 promoter ('Module 1'), an FRT cassette containing 5xUAS regulatory sequences plus a minimal Hsp70 promoter ('Module 2'), and a loxP cassette containing 5xQUAS regulatory sequences plus a minimal Hsp70 promoter ('Module 3'). The use of incompatible recombination sites flanking each regulatory sequence module allows them to be excised singly or in combination depending on the specific recombinase(s) used.

UAS sequences regulate expression of the wild-type Dronc sequence, tagged at the C-terminal end with GFP into which a Dronc-specific cleavage site (TETDG) has been inserted, followed by Tag:MYC. The GFP moiety does not fluoresce unless cleavage occurs at the TETDG site; cleavage induces a conformational rearrangement of the protein that results in green fluorescent emission. The construct allows the simultaneous assessment of Dronc protein abundance (Tag:MYC immunostaining) and activation status (GFP fluorescence).