The loxP cassette present in the inserted P{EP(loxP.UAS)y+.UAS} element has been excised, removing the 5' UAS sites. GAL4-mediated expression from the UAS sites present in the P{EP(-loxP)y+.UAS}cdi44-004y- insertion results in an increase in transcription of both the mRpL55 and cdi genes.
The suppression of the rough eye phenotype of sevS11.T:Hsap\MYC flies seen when mRpL55 and cdi expression is driven by Scer\GAL4hs.2sev from the Scer\UAS sites present in the P{EP.Scer\UAS.(-loxP).BN}cdi44-004y- insertion is due to the increase in cdi expression, since expression of the P{UAS-cdi.S} construct recapitulates the suppression, while expression of the P{UAS-mRpL55.S} construct does not.