TRF2 mediates force-resistant bridging of distal telomeric DNA repeats

Abstract

Shelterin binds telomeres, regulates telomere length, and protects chromosome ends from mis-repair, which is essential for genome stability. Telomere end-protection uniquely depends on the TRF2 subunit, which assembles telomeric DNA into a protective T-loop structure in vivo, yet the biochemical mechanism underlying this process remains unresolved. Using single-molecule optical tweezers and atomic force microscopy, we show that the human shelterin complex tethers distal telomeric DNA repeats, looping the intervening DNA. These bridges withstand tens of piconewtons of applied load, rupture at a force that scales with telomeric repeat number and re-form on relaxation. Structure-function analysis demonstrates that this force-resistant tethering is TRF2-dependent under our conditions and depends on multiple interfaces, with the TRFH domain making a major but non-exclusive contribution: introducing the TRF2 TRFH domain into TRF1 is sufficient to confer tethering, whereas its deletion from TRF2 reduces but does not abolish activity. We propose telomeric dsDNA tethering by TRF2 as a candidate first step in T-loop formation, preceding invasion of the telomeric 3' ssDNA overhang.

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BibTeX RIS

BibTeX

@misc{newton2026trf2,
  title = {{TRF2 mediates force-resistant bridging of distal telomeric DNA repeats}},
  author = {M. D. Newton and T. E. Catley and S. Whittle and L. Galanti and L. L. Wiggins and E. P. Holmes and D. Daccache and R. Anand and E. G. Allwood and M. Greensill and S. Segura-Bayona and O. Belan and M. C. Gamill and S. Maslen and M. Skehel and A. L. B. Pyne and S. J. Boulton},
  howpublished = {bioRxiv},
  year = {2026},
  month = oct,
  doi = {10.64898/2026.10.09.757630},
  url = {https://www.biorxiv.org/content/10.64898/2026.10.09.757630v1},
  note = {CC BY-NC-ND},
}

RIS

TY  - UNPB
TI  - TRF2 mediates force-resistant bridging of distal telomeric DNA repeats
AU  - M. D. Newton
AU  - T. E. Catley
AU  - S. Whittle
AU  - L. Galanti
AU  - L. L. Wiggins
AU  - E. P. Holmes
AU  - D. Daccache
AU  - R. Anand
AU  - E. G. Allwood
AU  - M. Greensill
AU  - S. Segura-Bayona
AU  - O. Belan
AU  - M. C. Gamill
AU  - S. Maslen
AU  - M. Skehel
AU  - A. L. B. Pyne
AU  - S. J. Boulton
PY  - 2026
DA  - 2026/10/09
PB  - bioRxiv
DO  - 10.64898/2026.10.09.757630
UR  - https://www.biorxiv.org/content/10.64898/2026.10.09.757630v1
AB  - Shelterin binds telomeres, regulates telomere length, and protects chromosome ends from mis-repair, which is essential for genome stability. Telomere end-protection uniquely depends on the TRF2 subunit, which assembles telomeric DNA into a protective T-loop structure in vivo, yet the biochemical mechanism underlying this process remains unresolved. Using single-molecule optical tweezers and atomic force microscopy, we show that the human shelterin complex tethers distal telomeric DNA repeats, looping the intervening DNA. These bridges withstand tens of piconewtons of applied load, rupture at a force that scales with telomeric repeat number and re-form on relaxation. Structure-function analysis demonstrates that this force-resistant tethering is TRF2-dependent under our conditions and depends on multiple interfaces, with the TRFH domain making a major but non-exclusive contribution: introducing the TRF2 TRFH domain into TRF1 is sufficient to confer tethering, whereas its deletion from TRF2 reduces but does not abolish activity. We propose telomeric dsDNA tethering by TRF2 as a candidate first step in T-loop formation, preceding invasion of the telomeric 3' ssDNA overhang.
ER  -

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