title: Human Ku70/80 associates physically with telomerase through interaction with hTERT.
abstract: Telomere length maintenance, an activity essential for chromosome stability and genome integrity, is regulated by telomerase- and telomere-associated factors. The DNA repair protein Ku (a heterodimer of Ku70 and Ku80 subunits) associates with mammalian telomeres and contributes to telomere maintenance. Here, we analyzed the physical association of Ku with human telomerase both in vivo and in vitro. Antibodies specific to human Ku proteins precipitated human telomerase in extracts from tumor cells, as well as from telomerase-immortalized normal cells, regardless of the presence of DNA-dependent protein kinase catalytic subunit. The same Ku antibodies also precipitated in vitro reconstituted telomerase, suggesting that this association does not require telomeric DNA. Moreover, Ku associated with the in vitro translated catalytic subunit of telomerase (hTERT) in the absence of telomerase RNA (hTR) or telomeric DNA. The results presented here are the first to report that Ku associates with hTERT, and this interaction may function to regulate the access of telomerase to telomeric DNA ends.
authors.affiliation: Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9039, USA.
authors.forename: Weihang
authors.initials: W
authors.lastname: Chai
authors.forename: Lance P
authors.initials: LP
authors.lastname: Ford
authors.forename: Lisa
authors.initials: L
authors.lastname: Lenertz
authors.forename: Woodring E
authors.initials: WE
authors.lastname: Wright
authors.forename: Jerry W
authors.initials: JW
authors.lastname: Shay
mesh_terms: D034961:Antigens, Nuclear; D020134:Catalytic Domain; D004265:DNA Helicases; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D000072200:Ku Autoantigen; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D019098:Telomerase / Q000737:chemistry / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D034961:Antigens, Nuclear; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D019098:Telomerase; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen