Age-associated increase of spontaneous mutant frequency and molecular nature of mutation in newborn and old lacZ-transgenic mouse

Tetsuya Ono, Hironobu Ikehata, Shingo Nakamura, Yusuke Saito, Yoshio Hosoi, Yoshihiro Takai, Shogo Yamada, Junichi Onodera, Kazuo Yamamoto

Research output: Contribution to journalArticlepeer-review

78 Citations (Scopus)

Abstract

Accumulation of mutation has long been hypothesized to be a cause of aging and contribute to many of the degenerative diseases, which appear in the senescent phase of life. To test this hypothesis, age-associated changes in spontaneous mutation in different tissues of the body as well as the molecular nature of such changes should be examined. This kind of approach has become feasible only lately with a development of new transgenic mice suitable for mutation assay. Here, using one of these transgenic mice harboring lacZ gene, we have shown that the age-associated increase in spontaneous mutant frequency is common to all tissues examined; spleen, liver, heart, brain, skin and testis, while the rates of increase in mutant frequency differed among the tissues. DNA sequencing of the 496 lacZ mutants recovered from the tissues of newborn and old mice has revealed that spectra of mutations are similar at the two age points with G:C to A:T transition at CpG site being a predominant type of mutation. Furthermore, some mutations in old tissues are complex type and not found in tissues of newborn mice. These results suggest that similar mechanisms may be operating for mutation induction in fetal and postnatal aging process. In addition, the appearance of complex types of mutations in the old tissues suggests a unique cause for these mutations in aging tissues. (C) 2000 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)165-177
Number of pages13
JournalMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
Volume447
Issue number2
DOIs
Publication statusPublished - 2000 Feb 14

Keywords

  • Aging
  • DNA sequence
  • LacZ
  • Mutation
  • Transgenic mouse

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Health, Toxicology and Mutagenesis

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