Expression of telomerase subunits and localization of telomerase activation in hydatidiform mole

Activation of telomerase compensating for the loss of telomeres has been im plicated in human cell immortalization and carcinogenesis. Telomeric repeat amplification protocol (TRAP:) assay can be used to detect telomerase acti vity in a variety of malignant tumours, including those of the female repro ductive tract which have been found to have high levels of telomerase activ ity. However, it is unclear whether all the cells or only a subset of cells within a tumour have telomerase activity. To determine the regulation mech anism of telomerase activity in hydatidiform moles, we studied telomerase a ctivity at the single cell level(using an in situ TRAP assay), and expressi on of TLP1 (telomerase protein 1), TERC (telomerase RNA component) and TERT (telomerase reverse transcriptase component). Expression of TERC and TLP1 was observed in all normal chorionic villi, as well as in trophoblastic dis eases, and various cell lines irrespective of telomerase activity. TERT exp ression was observed in trophoblastic diseases and normal chorionic villi w ith telomerase activity but not in normal chorionic villi without telomeras e activity, except in some cases in he present series, indicating that TERT expression is closely associated with telomerase activity. Upregulation of TERT expression may thus play an important role in telomerase reactivation . (C) 1999 W. B. Saunders Company Ltd.