The αTub84B promoter is separated from the GAL4 driver coding region by an FRT cassette containing Scer\GAL80αTub84B.PC and y+t*.
GAL80 is expressed under the control of the αTub84B promoter.
Expression of ScerGAL4 is suppressed the expression of ScerGAL80; expression of ScerGAL80 isby blocked by a ScerFRT-flanked segment; exposure to ScerFLP1 results in excision of this segment.