Abstract
The identities and roles of proteins associated with human telomerase remain poorly defined. To gain insight, we undertook an affinity purification of endogenously assembled human telomerase complexes. We show that specific subsets of H/ACA, Sm, and hnRNP proteins associate with active and inactive telomerase RNPs, while two NTPase proteins associate preferentially with active enzyme. All three core H/ACA-motif binding proteins are telomerase holoenzyme components essential for RNP accumulation. On the other hand, telomerase RNPs lacking interaction with Sm proteins or hnRNP C remain fully functional for telomere elongation. Curiously, overexpression of either associated hnRNP protein (hnRNP C and hnRNP U) or either NTPase protein (NAT10 and GNL3L) induced telomere shortening. Our findings suggest that endogenous human telomerase complexes are more heterogeneous than those of single-celled eukaryotes, have predominantly shared rather than telomerase-specific proteins, and make numerous regulatory interactions.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Acetyltransferases / genetics
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Acetyltransferases / metabolism
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Cells, Cultured
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Chromatography, Affinity
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GTP-Binding Proteins / genetics
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GTP-Binding Proteins / metabolism
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Heterogeneous-Nuclear Ribonucleoprotein Group C / genetics
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Heterogeneous-Nuclear Ribonucleoprotein Group C / metabolism
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Heterogeneous-Nuclear Ribonucleoprotein U / genetics
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Heterogeneous-Nuclear Ribonucleoprotein U / metabolism
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Holoenzymes / genetics
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Holoenzymes / isolation & purification
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Holoenzymes / metabolism*
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Humans
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N-Terminal Acetyltransferase E
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N-Terminal Acetyltransferases
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Protein Binding
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RNA
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RNA, Long Noncoding
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RNA, Untranslated / genetics
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RNA, Untranslated / metabolism*
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Ribonucleoproteins, Small Nuclear / genetics
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Ribonucleoproteins, Small Nuclear / metabolism
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Telomerase / genetics
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Telomerase / isolation & purification*
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Telomerase / metabolism*
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Telomere / genetics*
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Telomere / metabolism
Substances
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GNL3L protein, human
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HNRNPC protein, human
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Heterogeneous-Nuclear Ribonucleoprotein Group C
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Heterogeneous-Nuclear Ribonucleoprotein U
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Holoenzymes
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Nuclear Proteins
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RNA, Long Noncoding
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RNA, Untranslated
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Ribonucleoproteins, Small Nuclear
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telomerase RNA
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RNA
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Acetyltransferases
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N-Terminal Acetyltransferase E
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N-Terminal Acetyltransferases
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NAT10 protein, human
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TERT protein, human
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Telomerase
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GTP-Binding Proteins