Identification of the translation products of the XAGE-1 variants. (A) Schematic representation of the XAGE-1 variants. Exons (gray boxes), introns (open boxes) and putative open reading frames (narrow boxes) are shown. The solid box represents the epitope of USO9-13 mAb. The asterisk indicates the translation initiation site of XAGE-1b. (B) Immunoblotting of lysate of 293T cells transiently transfected with pcDNA3.1/XAGE-1a, b, c and d with USO9-13 mAb. (C) M1, M2 and M3 are pcDNA3.1/XAGE-1c mutants that lack the second and/or the third internal ATG codons. (D) Immunoblotting of lysate of 293T cells transiently transfected with pcDNA3.1/XAGE-1b and c, and M1, M2 and M3 using USO9-13 mAb. (E) Schematic representation of the translation products of the XAGE-1 variants. Exons (gray boxes), introns (open boxes) and defined open reading frames (narrow boxes) are shown. The solid box represents the epitope of USO9-13 mAb.