α2–6 sialylation of β
integrins in ST6Gal-I-expressing OV4 cells. Parental OV4 cells (P) were stably transduced with a lentiviral vector encoding an ST6Gal-I cDNA fused to a V5 tag (ST6). Cells were also transduced with an empty lentiviral vector as a control (EV). A, Cell lysates were immunoblotted for the V5 tag (left panel) or for ST6Gal-I (right panel) to verify successful transduction of the ST6Gal-I construct. B, Lysates from P, EV, and ST6 cells were SNA-precipitated and immunoblotted for β1 integrins to monitor levels of integrin sialylation. Lysates were also immunoblotted for total levels of β1. As shown, expression of ST6Gal-I in OV4 cells caused β1 integrins to become α2–6 sialylated, verifying that the transduced enzyme was active.