The P{lexAop-UAS-mOrange.CAAX.K} construct was generated in vivo, by activation of the P{Raeppli-CAAX} construct, a two-step process in which FLP recombinase is first used to allow expression of the phiC31:int coding region present in the starting construct, which then subsequently promotes site-specific recombination between a single attB site and one of several attP sites in the starting construct. This results in the stable selection of one of several fluorescent markers present in the starting construct (only the fluorescent protein brought closest to the regulatory sequences is expressed as a stop codon is present after each fluorescent marker coding region). The P{lexAop-UAS-mOrange.CAAX.K} construct expresses the mOrange fluorescent protein.

lexAop and UAS regulatory sequences are followed by a minimal heat shock promoter and the mOrange fluorescent protein tagged with a membrane targeting sequence (Tag:CAAX(Unk)). The lexAop and UAS regulatory sequences are flanked by loxP and lox2272 sites respectively (meaning that the P1cre recombinase can be used to excise one of the enhancers in a mutually exclusive manner if desired).