The accumulation of SUMO conjugates is dependent on virus reactivation.

(A) Western blots of untreated and anti-IgG treated EBV negative Akata and EBV positive Akata-Bx1 and TPA/Bu treated EBV negative AGS and EBV positive AGS-Bx1 were probed with antibodies to SUMO2/3, BZLF1 and β-actin. Induction of the productive virus cycle was accompanied by accumulation of poly-SUMOylated proteins in the EBV positive cell lines. (B) The intensities of the SUMO2/3 reactive bands were quantified by densitometry. The average increase relative to untreated controls in two independent experiments is shown in the figure.