Vergleichende Untersuchung der Telomerverlängerungsmechanismen in Zellen mit normalem und aberrantem Karyotyp

Abstract

In human tumor cells, two types of telomere maintenance mechanisms are described: one depends on the synthesis of telomeric repeats by the enzyme telomerase, the other on the so-called alternative pathway (ALT), which is based on telomere recombination. In this study different tumor cell lines and lymphoblastoid cell lines were examined for their telomerase activity via immunhistochemistry and TRAP assay and their ALT pathway through the enzymes RPA-2 and RPA-4. All examined cell lines showed positive telomerase activity which was negatively correlated with donor age. A possible relation with immortalisation by Epstein-Barr virus and histological origin is discussed. Although RPA-2 and RPA-4 are parts of the replication protein complex and involved in DNA repair via homologous recombination, both enzymes turn out not to be useful markers for the ALT pathway.