UASt regulatory sequences drive expression of the IIa isoform of Ubx.
The partial transformation of haltere into wing which is seen in UbxLDN/Ubxabx-1 Ubxbx-3 Ubxpbx-1 flies is strongly suppressed by expression of UbxIIa.Scer\UAS.cRa under the control of Scer\GAL4Ubx-LDN.