Telomere dynamics: the means to an end

Abstract

Telomeres are among the most important structures in eukaryotic cells. Creating the physical ends of linear chromosomes, they play a crucial role in maintaining genome stability, control of cell division, cell growth and senescence. In vertebrates, telomeres consist of G-rich repetitive DNA sequences (TTAGGG)n and specific proteins, creating a specialized structure called the telosome that through mutual interactions with many other factors in the cell give rise to dynamic regulation of chromosome maintenance. In this review, we survey the structural and mechanistic aspects of telomere length regulation and how these processes lead to alterations in normal and immortal cell growth.

Figure 1

Telomeres are complex and dynamic structures. The core telomere complex consists of six telomeric DNA binding proteins that interact dynamically with various other protein factors, including DNA repair proteins, DNA processing enzymes, single‐stranded DNA binding proteins and in human cells, tankyrase. Tankyrase modifies TRF1 releasing it from telomeric DNA; this contributes to conformational change in the telomeric structure, promotes telomerase access to the 3′‐single‐stranded telomere end.