UAS regulatory sequences drive expression of ftz coding sequences with a mutation of the hox-like LRALL motif to LRAAA and of the Exd/Pbx binding FNWS domain to AAAA.
Expression of ftzLRAAA.AAAA.Scer\UAS in developing imaginal discs under the control of Scer\GAL4Dll-md23 results in antennae with normal A1 and A2 segments, but a malformed A3 segment with extra bristles and a truncated arista.