Tyrosine phosphorylation of cdc2 in uninfected and HHV-7–infected (12 days p.i.) SupT1 cells. Equivalent amounts of protein lysates obtained from uninfected (lane 1) and HHV-7–infected (lane 2) cells were analyzed by Western blot with an anti–P-Tyr MoAb. Migration of a major tyrosine-phosphorylated substrate is indicated by the asterix. Molecular size markers are indicated on the left (in kilodaltons). The relative intensities of the bands were densitometrically quantified and expressed in arbitrary units (a.u.). These results are representative of three experiments performed.