UASt regulatory sequences drive expression of sns, in which all 5 potential PDZ-domain binding motifs have been mutated (amino acid replacements D1135N, V1137G, E1140Q, L1142G, S1143A, V1145G, T1173A, L1175G, V1176G, E1177Q, L1481G and V1482G). The coding sequence is tagged at the C-terminal end with a single Tag:HA tag.