Cells grown in 60-mm dishes were transfected with 2 mg of plasmid as indicated in Figure 2 ; the Lipofectamine and Plus reagents (Invitrogen/Life Technologies, Carlsbad, CA) were used as previously described [79] . For some of the transfection experiments, HEK293 cells were cotransfected with 2 mg of pHelper plasmid (Agilent), which contains the adenovirus 5 (Ad5) E2a, E4orf6, and VA genes, or infected with adenovirus type 5 (Ad) at an MOI of 5 as previously described [79] .