Telomere maintenance and DNA replication: how closely are these two connected?

The maintenance of the DNA at chromosome ends, the telomeres, depends on conventional semiconservative replication and on the action of telomerase, a specialized reverse transcriptase. Current research strongly suggests a regulatory interplay between this conventional semiconservative replication and telomerase, thus ensuring that no sequences are lost at the very ends of the telomeres during replication. Here, we describe recent findings on the interactions between the conventional replication machinery and telomere replication, and we discuss how DNA-integrity checkpoints might impinge on both the processing of the telomeric DNA ends and the establishment of the DNA end structure required for end protection and genome stability.