Monovalent cation-induced structure of telomeric DNA: The G-quartet model

Journal Article · Fri Dec 01 00:00:00 EST 1989 · Cell; (USA)

DOI:https://doi.org/10.1016/0092-8674(89)90610-7· OSTI ID:5045612

Williamson, J R; Raghuraman, M K; Cech, T R ^[1]

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1. Howard Hughes Medical Institute, Boulder, CO (USA)

We have investigated the structures formed by oligonucleotides composed of two or four repeats of the telomeric sequences from Oxytricha and Tetrahymena. The Oxytricha four-repeat molecule (d(T4G4)4 = Oxy-4) forms structures with increased electrophoretic mobility in nondenaturing gels containing Na+, K+, or Cs+, but not in gels containing Li+ or no added salt. Formation of the folded structure results in protection of a set of dG's from methylation by dimethyl sulfate. Efficient UV-induced cross-links are observed in Oxy-4 and the related sequence from Tetrahymena (d(T2G4)4 = Tet-4), and join thymidine residues in different repeats. Models proposed to account for these data involve G-quartets, hydrogen-bonded structures formed from four guanosine residues in a square-planar array. We propose that the G-quartet structure must be dealt with in vivo by the telomere replication machinery.

• OSTI ID: 5045612
• Journal Information: Cell; (USA), Journal Name: Cell; (USA) Vol. 59:5; ISSN CELLB; ISSN 0092-8674
• Country of Publication: United States
• Language: English

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