Assembly and function of the telomerase enzyme complex

Abstract

Publisher Summary Telomerases are ribonucleoprotein complexes that synthesize telomeric repeats on the chromosome end—the telomere. They are reverse transcriptases because they copy a built-in template, which is part of the integral RNA component of the enzyme and functions like a blueprint for new telomeric repeats. This chapter describes the components and functions of the telomerase enzyme complex. The chapter focuses on the description of the human enzyme; and also reviews the telomerases from other species. The activity of telomerase detected by in vitro activity assays is sensitive to both, proteinase and RNase digestion; thus telomerases are ribonucleoprotein enzymes that consist of protein and RNA components. Telomerases synthesize multiple telomeric repeats on short single stranded DNA oligonucleotides in vitro or on chromosome ends in vivo. Two components of the telomerase enzyme, the RNA component (hTR) and human telomerase reverse transcriptase (hTERT)—the catalytic subunit are considered as the core components. Only hTERT seems to correlate with telomerase activity in vivo.