Do telomeres ask checkpoint proteins: "gimme shelter-in"?
Telomeres are complicated structures designed to allow one thing and avoid another. They allow replication of chromosome ends, an issue mostly about telomerase, which we seem to understand (though details of its regulation are works in progress). Telomeres must also avoid being detected as DNA breaks. This is important for two reasons: DNA breaks activate checkpoints that cause arrest of cell division, and DNA breaks engage repair machinery. Clearly, normal telomeres neither activate cell cycle arrest nor allow themselves to be repaired; arrest blocks cell division, and repair fuses chromosomes.
Weinert
Ted
T
Department of Molecular & Cellular Biology, Life Sciences South Building, University of Arizona, Tucson, Arizona 85721, USA.
D004249:DNA Damage / Q000502:physiology; D004260:DNA Repair / Q000502:physiology; D018816:Genes, cdc / Q000502:physiology*; D006801:Humans; D019098:Telomerase / Q000378:metabolism; D016615:Telomere / Q000502:physiology*
D019098:Telomerase