Fig. 1.

FLAG-epitope-tagged EBNA1 transgene expression construct, functional test, and PCR detection of transgenes. (A) Transgene expression plasmid pEμPμFE1 is composed of Eμ and Pμ upstream of the FLAG-tagged EBNA1 ORF. (B) EBV-negative BJAB B lymphoblasts were transiently cotransfected with pEμPμFE1, pCDNAFE1, or pcDNA FLAG vector control, reporter plasmid pFL, and control pGKβ-galactosidase DNA. Relative luciferase activity is fold over the luciferase activity of pFL transfected with vector control DNA and was also corrected for transfection efficiency as assayed by β-galactosidase. (C) PCR screening used primer sets 1 and 2 to identify pEμPμFE1 DNA in 58, 68, and 73 founder mice among 25 progeny from embryo microinjections.