The effect of Pot1 binding on the repair of thymine analogs in a telomeric DNA sequence

Jacob A. Theruvathu, Agus Darwanto, Chia Wei Hsu, Lawrence Sowers

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Telomeric DNA can form duplex regions or single-stranded loops that bind multiple proteins, preventing it from being processed as a DNA repair intermediate. The bases within these regions are susceptible to damage; however, mechanisms for the repair of telomere damage are as yet poorly understood. We have examined the effect of three thymine (T) analogs including uracil (U), 5-fluorouracil (5FU) and 5-hydroxymethyluracil (5hmU) on DNA-protein interactions and DNA repair within the GGTTAC telomeric sequence. The replacement of T with U or 5FU interferes with Pot1 (Pot1pN protein of Schizosaccharomyces pombe) binding. Surprisingly, 5hmU substitution only modestly diminishes Pot1 binding suggesting that hydrophobicity of the T-methyl group likely plays a minor role in protein binding. In the GGTTAC sequence, all three analogs can be cleaved by DNA glycosylases; however, glycosylase activity is blocked if Pot1 binds. An abasic site at the G or T positions is cleaved by the endonuclease APE1 when in a duplex but not when single-stranded. Abasic site formation thermally destabilizes the duplex that could push a damaged DNA segment into a single-stranded loop. The inability to enzymatically cleave abasic sites in single-stranded telomere regions would block completion of the base excision repair cycle potentially causing telomere attrition.

Original languageEnglish (US)
Pages (from-to)9063-9073
Number of pages11
JournalNucleic Acids Research
Volume42
Issue number14
DOIs
StatePublished - 2014

Fingerprint

Thymine
Telomere
DNA Repair
Fluorouracil
DNA
Schizosaccharomyces pombe Proteins
DNA Glycosylases
Uracil
Endonucleases
Hydrophobic and Hydrophilic Interactions
Protein Binding
Proteins
5-hydroxymethyluracil

ASJC Scopus subject areas

  • Genetics

Cite this

The effect of Pot1 binding on the repair of thymine analogs in a telomeric DNA sequence. / Theruvathu, Jacob A.; Darwanto, Agus; Hsu, Chia Wei; Sowers, Lawrence.

In: Nucleic Acids Research, Vol. 42, No. 14, 2014, p. 9063-9073.

Research output: Contribution to journalArticle

Theruvathu, Jacob A. ; Darwanto, Agus ; Hsu, Chia Wei ; Sowers, Lawrence. / The effect of Pot1 binding on the repair of thymine analogs in a telomeric DNA sequence. In: Nucleic Acids Research. 2014 ; Vol. 42, No. 14. pp. 9063-9073.
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