DlR.UAS.FRT.Tag:MYC in which the peptide fused between Dl and Tag:MYC sequences has been mutated: GSWIPSFYNVVTGKTLALPNLIALQHIPLSPAGVIAKRPAPIALPNSCAA -> GSWIPSFYNVVTGrTLALPNLIALQHIPLSPAGVIArRPAPIALPNSCAA (mutated resides in lower case).