Recombinant Schizosaccharomyces pombe Nth1 protein exhibits DNA glycosylase activities for 8-oxo-7,8-dihydroguanine and thymine residues oxidized in the methyl group

Shin Ichiro Yonekura, Nobuya Nakamura, Takashi Doi, Hiroshi Sugiyama, Kazuo Yamamoto, Shuji Yonei, Qiu Mei Zhang

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11 Citations (Scopus)


Bacteria and eukaryotes possess redundant enzymes that recognize and remove oxidatively damaged bases from DNA through base excision repair. DNA glycosylases remove damaged bases to initiate the base excision repair. The exocyclic methyl group of thymine does not escape oxidative damage to produce 5-formyluracil (5-foU) and 5-hydroxymethyluracil (5-hmU). 5-foU is a potentially mutagenic lesion. A homolog of E. coli endonuclease III (SpNth1) had been identified and characterized in Shizosaccharomyces pombe. In this study, we found that SpNth1 recognizes and removes 5-foU and 5-hmU from DNA with similar efficiency. The specific activities for the removal of 5-foU and 5-hmU were comparable with that for thymine glycol. The expression of SpNth1 reduced the hydrogen peroxide toxicity and the frequency of spontaneous mutations in E. coli nth nei mutant. It was also revealed that SpNth1 had DNA glycosylase activity for removing 8-oxo-7,8-dihydroguanine (8-oxoG) from 8-oxoG/G and 8-oxoG/A mispairs. These results indicated that SpNth1 has a broad substrate specificity and is involved in the base excision repair of 8-oxoG and thymine residues oxidized in the methyl group in S. pombe.

Original languageEnglish
Pages (from-to)417-424
Number of pages8
JournalJournal of radiation research
Issue number5
Publication statusPublished - Sep 27 2007
Externally publishedYes



  • 5-formyluracil
  • 5-hydroxymethyluracil
  • 8-oxo-7,8- dihydroguanine
  • DNA glycosylase
  • Oxidative base damage
  • S. pombe Nth1

ASJC Scopus subject areas

  • Radiation
  • Radiology Nuclear Medicine and imaging
  • Health, Toxicology and Mutagenesis

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