Mutations and oxidative DNA damage in phage M13mp2 exposed to N-nitrosomorpholine plus near-ultraviolet light

Miho Fujiwara, Yuko Honda, Hideo Inoue, Hikoya Hayatsu, Sakae Arimoto

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Previously we reported that a direct-acting mutagen can be formed from N-nitrosomorpholine (NMOR) on exposure to near-ultraviolet light (UVA, 320-400 nm). We have now studied the spectrum of mutations caused by NMOR plus UVA. M13mp2 phages suspended in a sodium phosphate buffer were treated with NMOR under UVA irradiation and Escherichia coli NR9099 was then infected with the phage. Mutations induced in the phage DNA lacZα region were analyzed. The majority (~50%) of the induced sequence changes were G to T transversions. This suggested that modifications in guanine residues were responsible for these transversions. We explored the formation of 7,8-dihydro-8-oxodeoxyguanosine (8-oxodG) in the DNA. When the phage were treated with NMOR plus UVA, 8-oxodG/dG in DNA increased up to 12-fold over the value in untreated control. When a mutM-deficient mutant of E.coli CSH50 was used as the host, the mutation level was higher than that observed with CSH50. We conclude that 8-oxodG may be involved in mutations induced by NMOR plus UVA.

Original languageEnglish
Pages (from-to)213-218
Number of pages6
JournalCarcinogenesis
Volume17
Issue number2
DOIs
Publication statusPublished - Apr 2 1996

ASJC Scopus subject areas

  • Cancer Research

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