telomere assembly / positive regulation of hair cycle / template-free RNA nucleotidyltransferase activity / positive regulation of transdifferentiation / TERT-RMRP complex / DNA strand elongation / RNA-directed RNA polymerase complex / segmentation / siRNA transcription / urogenital system development ...telomere assembly / positive regulation of hair cycle / template-free RNA nucleotidyltransferase activity / positive regulation of transdifferentiation / TERT-RMRP complex / DNA strand elongation / RNA-directed RNA polymerase complex / segmentation / siRNA transcription / urogenital system development / positive regulation of protein localization to nucleolus / telomerase catalytic core complex / protection from non-homologous end joining at telomere / RNA-templated DNA biosynthetic process / establishment of protein localization to telomere / regulation of establishment of protein localization to telomere / telomerase activity / telomerase inhibitor activity / shelterin complex / Telomere C-strand synthesis initiation / Regulation of MITF-M-dependent genes involved in DNA replication, damage repair and senescence / siRNA processing / Telomere C-strand (Lagging Strand) Synthesis / nuclear telomere cap complex / telomere capping / telomere maintenance via recombination / positive regulation of vascular associated smooth muscle cell migration / telomerase holoenzyme complex / Polymerase switching on the C-strand of the telomere / telomerase RNA binding / embryonic limb morphogenesis / Processive synthesis on the C-strand of the telomere / Removal of the Flap Intermediate from the C-strand / protein localization to chromosome, telomeric region / DNA biosynthetic process / RNA-templated transcription / positive regulation of stem cell proliferation / telomeric repeat DNA binding / negative regulation of telomere maintenance via telomerase / positive regulation of telomere maintenance / negative regulation of cellular senescence / mitochondrial nucleoid / replicative senescence / Telomere Extension By Telomerase / negative regulation of extrinsic apoptotic signaling pathway in absence of ligand / response to cadmium ion / negative regulation of endothelial cell apoptotic process / positive regulation of G1/S transition of mitotic cell cycle / positive regulation of Wnt signaling pathway / telomere maintenance via telomerase / positive regulation of vascular associated smooth muscle cell proliferation / DNA polymerase binding / Packaging Of Telomere Ends / Recognition and association of DNA glycosylase with site containing an affected purine / Cleavage of the damaged purine / Recognition and association of DNA glycosylase with site containing an affected pyrimidine / Cleavage of the damaged pyrimidine / telomere maintenance / Inhibition of DNA recombination at telomere / Meiotic synapsis / positive regulation of D-glucose import across plasma membrane / skeletal system development / mitochondrion organization / regulation of protein stability / Formation of the beta-catenin:TCF transactivating complex / intracellular protein transport / PML body / RNA-directed DNA polymerase / positive regulation of miRNA transcription / DNA Damage/Telomere Stress Induced Senescence / transcription coactivator binding / RNA-directed DNA polymerase activity / positive regulation of angiogenesis / protein import into nucleus / structural constituent of chromatin / nucleosome / heart development / protein-folding chaperone binding / cellular response to hypoxia / negative regulation of neuron apoptotic process / tRNA binding / chromosome, telomeric region / nuclear speck / nuclear body / protein heterodimerization activity / RNA-directed RNA polymerase activity / protein-containing complex binding / nucleolus / protein homodimerization activity / DNA binding / RNA binding / nucleoplasm / metal ion binding / identical protein binding / nucleus / plasma membrane / cytosol 類似検索 - 分子機能
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
2R35GM122579
米国
Howard Hughes Medical Institute (HHMI)
米国
引用
ジャーナル: Nat Commun / 年: 2026 タイトル: Structures of nucleotide-bound human telomerase at several steps of its telomeric DNA repeat addition cycle. 著者: Sebastian Balch / Elsa Franco-Echevarría / George E Ghanim / Rachael C Kretsch / Rhiju Das / Thi Hoang Duong Nguyen / 要旨: In most eukaryotes, the reverse transcriptase telomerase counteracts telomere shortening by processively adding telomeric DNA repeat sequences to chromosome ends. Telomerase activity depends on the ...In most eukaryotes, the reverse transcriptase telomerase counteracts telomere shortening by processively adding telomeric DNA repeat sequences to chromosome ends. Telomerase activity depends on the telomerase reverse transcriptase (TERT) and the telomerase RNA (hTR in humans). Processive telomere elongation is critical for genome stability, and defects in this mechanism are linked to cellular dysfunction and human disease. However, the structural basis for telomerase repeat addition processivity in humans has remained elusive. Here, we present cryo-electron microscopy structures of human telomerase bound to telomeric DNA and an incoming nucleotide, captured at three distinct stages of its repeat addition cycle: initiation, elongation, and pre-termination. Across these states, the TERT active site maintains a conserved architecture that stabilises a short DNA-RNA duplex of constant length of four base-pairs. Beyond the active site, we identify dynamic structural features in both TERT and hTR that facilitate substrate engagement and RNA template repositioning, thereby supporting the synthesis of successive telomeric repeats. Together, these structures provide key insights into how human telomerase achieves its unique processivity to maintain telomere length and genome integrity.