UASt regulatory sequences drive expression of the N-terminal portion of hh (up to residue G257), fused at the C-terminal end with the C-terminal 54 amino acids of Fas1, with a mutation in the GPI-anchoring signal (the last 27 residues are replaced by a stop codon).
Clones in the wing disc expressing Fas1::hhΔGPI.Scer\UAS under the control of Scer\GAL4Act5C.PP result in an increase in size of the anterior compartment.