UASt regulatory sequences are fused upstream of a bicistronic transcript that encodes two open reading frames separated by stop codons (the upstream ORF is simply present to reduce translation of the Tag:Dam-containing downstream ORF). The downstream ORF comprises bsh that is tagged at the N-terminal end with Tag:Dam and a Tag:MYC epitope. The ORF is also tagged at the C-terminal end with three copies of the Tag:HA epitope.