FIG 4.

Construction of MCPyV-MuPyV, MCPyV-SV40 A, and MCPyV-SV40 B chimeric viruses. (A) The enhancer region of the MCPyV early promoter was replaced with the analogous region from the MuPyV genome. (B) Dermal fibroblasts isolated from human and rhesus macaque skin samples were transfected with the religated SV40 genome. After 5 days, all cells were immunostained using the indicated antibodies and counterstained with DAPI. Bar, 10 μm. (C) The enhancer region of the MCPyV early promoter was replaced with the analogous region of the SV40 genome. (D) The MCPyV late promoter region was deleted from the MCPyV-SV40 A genome. (E) The virus titers of MCPyV and the chimeric virions as represented by the genome copy numbers were determined by qPCR.