title: Limited capacity of the nuclear matrix to bind telomere repeat binding factor TRF1 may restrict the proliferation of mortal human fibroblasts.
abstract: The maintenance of telomere integrity is essential for prolonged cell proliferation, and failure in this mechanism is a most consistent manifestation of cellular senescence. In this study, we investigated the role of telomere repeat binding factor (TRF1) in the proliferation of human fibroblasts. TRF1 expression is upregulated in a large variety of immortal human cells and supports de novo telomere formation in a dose-dependent manner. These observations suggest that the suppression of TRF1 might limit telomere maintenance and thus the life span of mortal cells. However, primary fibroblasts ectopically overexpressing TRF1 were unable to avoid senescence. On the other hand, exogenously expressed TRF1 in primary fibroblasts neither supported de novo telomere formation nor bound to the nuclear matrix as tightly as observed in immortal cells that show upregulated TRF1 expression. We present evidence suggesting that mortal human cells lack specific ligand(s) that anchor TRF1 to the nuclear matrix and that this contributes to their limited lifespan.
authors.affiliation: Gene Function Research Center, National Institute of Advanced Industrial Science and Technology, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Okabe
authors.forename: Akiko
authors.initials: A
authors.lastname: Eguchi
authors.forename: Renu
authors.initials: R
authors.lastname: Wadhwa
authors.forename: Randeep
authors.initials: R
authors.lastname: Rakwal
authors.forename: Rumi
authors.initials: R
authors.lastname: Tsukinoki
authors.forename: Takao
authors.initials: T
authors.lastname: Hayakawa
authors.forename: Mahito
authors.initials: M
authors.lastname: Nakanishi
mesh_terms: D002455:Cell Division / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D015530:Nuclear Matrix / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism; D035321:Telomeric Repeat Binding Protein 1 / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D035321:Telomeric Repeat Binding Protein 1