UAS regulatory sequences drive expression of smo in which the three PKA sites (S667, S687 and S740) and adjacent CK1 sites have been mutated to Asp (phosphomimetic mutations) and which has a mutation at the sumoylation consensus site (amino acid replacement K851R, which diminishes both basal and hh-induced sumoylation in cultured cells). The protein is tagged at the N-terminal end with six copies of Tag:MYC.