Telomere size and telomerase activity in Epstein-Barr virus (EBV)-positive and EBV-negative Burkitt's lymphoma cell lines.

The telomere repeat lengths of BL cell lines were quantified by measuring terminal restriction fragment (TRF). Epstein-Barr virus (EBV)-positive Namalwa, Raji, and EB-3 cell lines have long telomeres, i.e. TRFs 10–19 kbp, whereas the Daudi cell line, producing a transformation-defective EBV mutant, has TRFs ∼2.2 kbp. EBV-negative BJAB and DG75 cell lines have short TRFs 3.9–5.4 kbp, shorter than the ∼12 kbp TRFs in PBLs. Telomerase activities of these BL cell lines are similar. TRFs of non-BL lymphoma cell lines are 2.3–5.5 kbp. Fluorescent in situ hybridization (FISH) studies of these cell lines showed remarkable heterogeneity of telomere size in chromosomes in the same BL cell. These results suggest that EBV-positive and EBV-negative BL cell lines have experienced various telomere dynamics.