Fig 2.

E4orf6 is required for induction of B19V DNA synthesis in 293 cells. 293 cells were cotransfected with 1 μg of SalI-linearized pB19-M20 DNA and increasing amounts (25 ng, 100 ng, 250 ng, and 1 μg) of either pHelper or the isolated pHelper functions E2a, E4orf6, or VA RNA as indicated. Adjustment of the total amount of DNA to 4 μg was performed with the pCATCH plasmid. (A) Southern blot detection of DpnI-resistant B19V replicative intermediates essentially as described in the legend to Fig. 1A, except that a [³²P]dCTP-labeled hybridization probe was used. (B) Immunoblot analysis for B19V VP expression with the monoclonal antibody MAB8293, as described for Fig. 1B.