Telomeric chromatin: replicating and wrapping up chromosome ends

Recent advances in our understanding of the specialized chromatin structure at telomeres, the ends of eukaryotic chromosomes, have focused on three se parate areas: replication of telomeres through the coordinated action of co nventional DNA polymerases and the telomerase enzyme, protection of the chr omosome end from DNA damage checkpoint sensors and DNA-repair processes, an d the discovery of a novel deacetylase enzyme (Sir2p) required for the esta blishment and maintenance of telomeric heterochromatin. Although the number of proteins and the complexity of their interactions at telomeres continue s to grow, a picture of at least some of the major players and mechanisms u nderlying telomere replication, end 'capping' and chromatin assembly is beg inning to emerge.