EBNA1 expression leads to increased levels of EBER expression. RT-PCR assay for (a) tRNATyr and EBER expression in response to transient expression of increasing amounts of EBNA1 in the EBER-expressing cell line Ad/AH-EBERs. The experiments were conducted in biological triplicate. Numbers below the bands in the EBER1, EBER2 and tRNA rows represent the mean fold increase (± SD) in expression between the EBNA1-positive cells and the control as assessed by densitometry. (b) RT-PCR comparing EBER and EBNA1 expression in AdAH cell lines with levels seen in the Burkitt's lymphoma-derived cell line, Namalwa. (c) EBER expression in Ad/AH-rEBV cells transiently transfected with dominant negative EBNA1 vector or pSG5 control plasmid. Numbers to the right indicate the mean fold decrease (± SD) of EBER expression in triplicate experiments.