Maintenance on the expression of mycTRF2 after induction of LMP1 abolishes multinuclearity. (A) Representative western blot for the expression of mycTRF2, TRF2, and TRF1 in cells exposed for 3 days to the removal of tetracycline. Upper panel: LMP1 expression. Middle panel: expression of mycTRF2 revealed with anti-myc antibody. Lower panel: expression of TRF2 and TRF1 compared with α-tubulin as loading control, using a mix of antibody. In the double stable transfectant BJAB-tTA-LMP1/mycTRF2 (lanes 5 and 6) mycTRF2 is equally expressed independent of LMP1 expression, whereas total TRF2 (LMP1-dependent TRF2 and mycTRF2) is high in the presence of tetracycline (LMP1 suppressed, lane 5) but equal to mycTRF2 in the absence of tetracycline (LMP1 expressed, lane 6). Note also the LMP1-induced suppression of TRF1 (lanes 4 and 6). (B) Count of multinucleated cells by using the Operetta system in the presence or absence of tetracycline over a period of 10 days. Cell line analyzed is indicated in top of each panel. LMP1 expression results in a significant increase of bi- or multinuclear cells only in the BJAB-tTA-LMP1–induced cells (mid panel), whereas LMP1-independent, CMV-driven TRF2 expression compensates the LMP1-induced TRF2 suppression, abolishing multinucleation (bottom panel). Based on 3 independent experiments. *P < .05, Student t test).