Telomeres are nucleo-protein structures that protect chromosome ends against degradation, fusion, recombination and recognition by the DNA damage machinery and at the same time facilitate replication of the ends of linear eukaryotic chromosomes. The maintenance of telomere length depends on telomerase, a ribonucleoprotein complex that uses its RNA template to elongate the telomere by addition of G-rich telomeric repeats to the terminal 3' overhang. Synthesis of the complementary 5' C-rich telomeric strand is driven by conventional DNA polymerases.
