DNA structure-dependent recruitment of telomeric proteins to single-stranded/double-stranded DNA junctions

Biochem Biophys Res Commun. 2005 Mar 4;328(1):49-56. doi: 10.1016/j.bbrc.2004.12.134.

Abstract

Telomeres protect chromosome ends by assembling unique protein-DNA complexes. TRF2 is a telomere binding protein that is involved in protecting the G-strand overhang, a 3', guanine-rich, overhang at the telomere terminus. TRF2 may protect the G-strand overhang by recognizing some organizational aspect of the telomeric single-stranded/double-stranded (ss/ds) DNA junction. This work demonstrates that TRF2, purified or in crude extracts, recognizes telomeric ss/ds DNA junctions containing wild type telomeric sequence in the ds region and a G-strand overhang with at least one telomeric repeat. Telomeric complexes containing TRF2 and pot1 assemble less efficiently when the G-strand overhang is in the form of an intramolecular G-quadruplex. However, recruitment of the DNA repair proteins, WRN, Mre11, and Ku86, is not inhibited by a G-quadruplex. This suggests that an intramolecular G-quadruplex has the potential to disrupt certain telomeric assemblies, but efficient recruitment of appropriate DNA repair proteins provides the means to overcome this obstacle.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • DNA / chemistry*
  • DNA Repair
  • DNA, Single-Stranded / chemistry
  • Humans
  • Macromolecular Substances / chemistry
  • Nucleic Acid Conformation
  • Protein Binding
  • Shelterin Complex
  • Structure-Activity Relationship
  • Telomere-Binding Proteins / chemistry*
  • Telomeric Repeat Binding Protein 2 / chemistry*

Substances

  • DNA, Single-Stranded
  • Macromolecular Substances
  • POT1 protein, human
  • Shelterin Complex
  • Telomere-Binding Proteins
  • Telomeric Repeat Binding Protein 2
  • DNA