Telomere Science Library

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about the Nobel-Prize Winning Science of Telomere Biology

Structure of Tetrahymena telomerase reveals previously unknown subunits, functions, and interactions.

Authors: Jiansen J. Jiang, Henry H. Chan, Darian D DD. Cash, Edward J EJ. Miracco, Rachel R RR. Ogorzalek Loo, Heather E HE. Upton, Duilio D. Cascio, Reid R. O'Brien Johnson, Kathleen K. Collins, Joseph A JA. Loo, Z Hong ZH. Zhou, Juli J. Feigon
Published: 10/15/2015, Science (New York, N.Y.)


Telomerase helps maintain telomeres by processive synthesis of telomere repeat DNA at their 3'-ends, using an integral telomerase RNA (TER) and telomerase reverse transcriptase (TERT). We report the cryo-electron microscopy structure of Tetrahymena telomerase at ~9 angstrom resolution. In addition to seven known holoenzyme proteins, we identify two additional proteins that form a complex (TEB) with single-stranded telomere DNA-binding protein Teb1, paralogous to heterotrimeric replication protein A (RPA). The p75-p45-p19 subcomplex is identified as another RPA-related complex, CST (CTC1-STN1-TEN1). This study reveals the paths of TER in the TERT-TER-p65 catalytic core and single-stranded DNA exit; extensive subunit interactions of the TERT essential N-terminal domain, p50, and TEB; and other subunit identities and structures, including p19 and p45C crystal structures. Our findings provide structural and mechanistic insights into telomerase holoenzyme function.

Copyright © 2015, American Association for the Advancement of Science.
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