UASt regulatory sequences are fused upstream of a bicistronic transcript that encodes two open reading frames separated by stop codons (the upstream ORF encodes myristylated GFP and is simply present to reduce translation of the Tag:Dam-containing downstream ORF). The downstream ORF encodes the MRG15-RA isoform, tagged at the N-terminal end with Tag:Dam and a Tag:MYC epitope.