The FRT cassette containing the E(spl)mβ-HLH gene has been excised from M{E(spl)-mδ(FRT)-mβ(FRT)-m3GFP}, resulting in a genomic fragment that encompasses the entire E(spl)-complex but lacks both the E(spl)m3-HLH and E(spl)mβ-HLH open reading frames (the E(spl)m3-HLH open reading frame has been replaced by the sfGFP coding region).