[Telomere DNA and telomerase of lymphoma-derived cell lines--telomere hypothesis for cell growth control].

Telomere is the specialized structure of chromosome end. Telomeric DNA is essential for stabilization of linear double-stranded DNA molecules. Human telomeric DNA comprises the tandem repeat (AATGGG)n. Telomeres of normal somatic cells shorten progressively on every cell division, and telomere length is considered to determine cellular proliferative capacity. Most normal cells except germ line cells lack telomerase activity. Evidence of telomerase reactivation in human cancer cells was reported in 1994. The telomere hypothesis of aging and cell immortalization has drawn much attention in recent years. We examined telomere DNA and telomerase activity of Burkitt's lymphoma cell lines and EBV-infected proliferating B lymphocytes. All of these cells had varied average size of TRFs and the cell lines of lymphoma origin showed elevated telomerase activity.