Interaction between pUL97 and cyclins B1, T1, and H depends on specific conditions provided by plasmid-transfected (A) or HCMV-infected cells (B). Note the strong interaction of cyclin B1 in both environments, which is strictly dependent on pUL97 activity, the relatively low signal of cyclin T1 interaction, which is independent of pUL97 activity, and the very strong cyclin H interaction, which is exclusively found within the environment of HCMV-infected cells. Note that Western blot splicing was performed to integrate the relevant lanes as indicated by vertical marking lines. This figure represents a refined illustration of previously published primary data (14). IP, immunoprecipitation;