UAS regulatory sequences drive expression of the Scr C terminus containing the YPWM motif and the homeodomain (HD). The homeodomain carries amino acid substitutions T6A and S7A (these mutations have been shown to result in a constitutively active variant in the full-length protein and they behave in a similar manner in the truncated peptide).
Expression of ScrAA.Scer\UAS under the control of Scer\GAL4hs.PB induces ectopic salivary glands in the embryonic head.
Ectopic expression of ScrAA.Scer\UAS under the control of Scer\GAL4Dll-md23 triggers homeotic transformation of the third antennal segment (A3) and the arista to a fully grown tarsus. The ectopic tarsi display one or two sex comb teeth indicating a prothoracic (T1) character.
Ectopic expression of ScrAA.Scer\UAS using Scer\GAL4dpp.blk1 induces strong eye phenotypes, ranging from reduction to the complete absence of eyes.