title: Different telomere damage signaling pathways in human and mouse cells.
abstract: Programmed telomere shortening in human somatic cells is thought to act as a tumor suppressor pathway, limiting the replicative potential of developing tumor cells. Critically short human telomeres induce senescence either by activating p53 or by inducing the p16/RB pathway, and suppression of both pathways is required to suppress senescence of aged human cells. Here we report that removal of TRF2 from human telomeres and the ensuing de-protection of chromosome ends induced immediate premature senescence. Although the telomeric tracts remained intact, the TRF2(DeltaBDeltaM)-induced premature senescence was indistinguishable from replicative senescence and could be mediated by either the p53 or the p16/RB pathway. Telomere de-protection also induced a growth arrest and senescent morphology in mouse cells. However, in this setting the loss of p53 function was sufficient to completely abrogate the arrest, indicating that the p16/RB response to telomere dysfunction is not active in mouse cells. These findings reveal a fundamental difference in telomere damage signaling in human and mouse cells that bears on the use of mouse models for the telomere tumor suppressor pathway.
authors.affiliation: Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, NY 10021, USA.
authors.forename: Agata
authors.initials: A
authors.lastname: Smogorzewska
authors.forename: Titia
authors.initials: T
authors.lastname: de Lange
mesh_terms: D000818:Animals; D002460:Cell Line; D016922:Cellular Senescence / Q000502:physiology; D002869:Chromosome Aberrations; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000502:physiology; D005347:Fibroblasts; D006801:Humans; D051379:Mice; D015398:Signal Transduction; D016615:Telomere / Q000502:physiology*; D035341:Telomeric Repeat Binding Protein 2; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D035341:Telomeric Repeat Binding Protein 2; D016159:Tumor Suppressor Protein p53