UAS regulatory sequences drive expression of a mutated form of smo (carries amino acid replacements S667E, L668E, D669E, S670E, E671D, I672S, S673E, S687E, V688E, D689E, S690E, Q691D, V692S, S693E, S740E, S741E, T742E, S743E, V744D, E745S and S746E).