An FRT cassette containing y+t7.7 and Rnor\Cd2 sequences separates UAS sequences from truncated Dl coding region fused in frame at the end of the sequence encoding 'ESYDSVTFDA' to sequence encoding 'GSWIPSFYNVVTGKTLALPNLIALQHIPLSPAGVIAKRPAPIALPNSCAA' followed by six tandem copies of Tag:MYC.