(A) Recombinant glucuronyltransferase fusion proteins expressed in Drosophila cells. Plasmids encoding intracellular (dGlcAT-P, dGlcAT-S) and secreted (dGlcAT-P sol, dGlcAT-S sol) fusion proteins with C-terminal V5 and 6 × His-Tags were generated. BiP, Hsc70-3 signal sequence; dGlcAT, Drosophila β1-3-glucuronyltransferase; V5, Paramyxovirus SV5-antigen. (B) Western blot analysis of cell supernatants and cell lysates of transfected Drosophila S2 cells with mAb anti-V5. 1, cell culture supernatant of S2-cells expressing dGlcAT-P sol; 2, culture supernatant of S2-dGlcAT-S sol; 3, cell lysate of S2-dGlcAT-P; 4, cell lysate S2-dGlcAT-S.