Figure 1.

EBV infection induces telomere dysfunction. (A) Representative experiment illustrating the comparable levels of cell proliferation recorded in mitogen-stimulated and EBV-infected cultures assessed by carboxyfluorescein diacetate succinimidyl ester (CFSE) dye incorporation. (B) Average number of cell division assessed by CFSE assays during the first 10 days of culture. Mean±s.e. of three experiments. (C) Representative micrographs illustrating the telomere abnormalities scored in metaphase plates of EBV-infected and mitogen-induced blasts. (A) heterogeneous telomere signals and chromosome juxtaposition by telomere fusion, (B) telomere fusion, (C) chromosome circle with telomere fusion, (D) juxtaposition of chromosomes with telomere fusion. Telomeres were stained by Q-FISH (red) and chromosomes were stained by 4,6-diamidino-2-phenylindole (DAPI; blue). (D) Mean±s.e. metaphases with telomere abnormalities in three independent experiments where EBV-infected and mitogen-induced blasts were tested in parallel. At least 25 metaphase plates were tested for each time point and condition. (E) Representative Q-FISH illustrating the occurrence of extra-chromosomal telomeres (ECT, arrows) in EBV-infected cells. The chromosomes were stained with DAPI (gray). (F) Quantification of the number of cells with ECT in EBV-infected and mitogen-stimulated cultures. Mean±s.e. of three experiments. *P<0.05.