FIG 1.

G4 BAC construction and in vitro characterization. (A) Schematic of BAC construction showing EcoRI restriction enzyme sites (E) and expected fragment sizes (double arrows). (B) RFLP of BAC constructs. The intermediate BAC (pG420) and repaired BAC (pG4209J) were digested with EcoRI and compared to DNA from the parental G4 virus. Solid arrows show DNA fragments unique to the parental virus; dashed arrows show DNA fragments unique to the BAC constructs. (C) Rescued virus (G4209) replicates like the wild type in vivo. Shown are the results of a multistep growth assay performed on MEFs; data are means ± standard deviations (SD) of duplicate data.