Telomerase Activity

Abstract

This chapter focuses on the structure and function of the telomere/telomerase complex, its regulation, the non telomeric activities of telomerase and diseases caused by alteration in the telomere/telomerase complex. Telomerase activity contains multiple factors that allow its regulation, including the expression of transcriptase component of telomerase (TERT) levels, post-transcriptional modifications, transportation and location and finally conformation and interactions with accessory proteins during assembly of the telomerase complex. TERT splice variants may be expressed in normal, pre- crisis and alternative lengthening of telomeres cells (ALT) that lack detectable telomerase activity. Interaction of telomerase with numerous telomere binding proteins (TBP) that may influence telomerase enzyme activity is considered another form of telomerase activity regulation. It is supposed that binding some of them to telomeres, therefore making it impossible for telomerase to access the chromosome ends, is an indirect way of regulation. Telomerase is essential for the long-term proliferation potential of stem cells and cancer cells, and for normal tissue renewal.