Abstract
The integral telomerase RNA subunit templates the synthesis of telomeric repeats. The biological accumulation of human telomerase RNA (hTR) requires hTR H/ACA domain assembly with the same proteins that assemble on other human H/ACA RNAs. Despite this shared RNP composition, hTR accumulation is particularly sensitized to disruption by disease-linked H/ACA protein variants. We show that contrary to expectation, hTR-specific sequence requirements for biological accumulation do not act at an hTR-specific step of H/ACA RNP biogenesis; instead, they enhance hTR binding to the shared, chaperone-bound scaffold of H/ACA core proteins that mediates initial RNP assembly. We recapitulate physiological H/ACA RNP assembly with a preassembled NAF1/dyskerin/NOP10/NHP2 scaffold purified from cell extract and demonstrate that distributed sequence features of the hTR 3' hairpin synergize to improve scaffold binding. Our findings reveal that the hTR H/ACA domain is distinguished from other human H/ACA RNAs not by a distinct set of RNA-protein interactions but by an increased efficiency of RNP assembly. Our findings suggest a unifying mechanism for human telomerase deficiencies associated with H/ACA protein variants.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Base Sequence
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Cell Cycle Proteins / chemistry
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Cell Cycle Proteins / metabolism
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HEK293 Cells
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HeLa Cells
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Humans
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Macromolecular Substances / chemistry
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Macromolecular Substances / metabolism
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Models, Molecular
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Nuclear Proteins / chemistry
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Nuclear Proteins / metabolism
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Nucleic Acid Conformation
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Protein Interaction Domains and Motifs
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Protein Multimerization
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RNA / chemistry*
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RNA / genetics
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RNA / metabolism
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RNA Polymerase II / genetics
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RNA Polymerase II / metabolism
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RNA Polymerase III / genetics
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RNA Polymerase III / metabolism
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Ribonucleoproteins / chemistry*
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Ribonucleoproteins / genetics
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Ribonucleoproteins / metabolism
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Ribonucleoproteins, Small Nuclear / chemistry
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Ribonucleoproteins, Small Nuclear / metabolism
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Ribonucleoproteins, Small Nucleolar / chemistry
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Ribonucleoproteins, Small Nucleolar / metabolism
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Telomerase / chemistry*
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Telomerase / genetics
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Telomerase / metabolism
Substances
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Cell Cycle Proteins
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DKC1 protein, human
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Macromolecular Substances
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NAF1 protein, human
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NHP2 protein, human
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NOP10 protein, human
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Nuclear Proteins
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Ribonucleoproteins
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Ribonucleoproteins, Small Nuclear
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Ribonucleoproteins, Small Nucleolar
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telomerase RNA
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RNA
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RNA Polymerase II
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Telomerase
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RNA Polymerase III