Other transgenic mutation assays: A new transgenic mouse mutagenesis test system using Spi− and 6-thioguanine selections

Nohmi, Takehiko; Katoh, Masaya; Suzuki, Hiroshi; Matsui, Michiko; Yamada, Masami; Watanabe, Masahiko; Suzuki, Makoto; Horiya, N.; Ueda, Otoya; Shibuya, Tohru; Ikeda, Hideo; Sofuni, Toshio

doi:10.1002/(sici)1098-2280(1996)28:4<465::aid-em24>3.0.co;2-c

Cited by 207 publications

(158 citation statements)

References 26 publications

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“…C57BL/6 gptΔ transgenic mice were a gift from T. Nohmi (45). The gptΔ B6C3F1 mice used here were generated by breeding female gptΔ C57BL/6J mice, which harbor an estimated 80 copies of the gpt gene on chromosome 17, with male C3H/HeJ mice purchased from The Jackson Laboratories.…”

Section: Methodsmentioning

confidence: 99%

Mutational spectra of aflatoxin B ₁ in vivo establish biomarkers of exposure for human hepatocellular carcinoma

Chawanthayatham

Valentine

Fedeles

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

109

113

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Aflatoxin B 1 (AFB 1 ) and/or hepatitis B and C viruses are risk factors for human hepatocellular carcinoma (HCC). Available evidence supports the interpretation that formation of AFB 1 -DNA adducts in hepatocytes seeds a population of mutations, mainly G:C→T:A, and viral processes synergize to accelerate tumorigenesis, perhaps via inflammation. Responding to a need for early-onset evidence predicting disease development, highly accurate duplex sequencing was used to monitor acquisition of high-resolution mutational spectra (HRMS) during the process of hepatocarcinogenesis. Four-day-old male mice were treated with AFB 1 using a regimen that induced HCC within 72 wk. For analysis, livers were separated into tumor and adjacent cellular fractions. HRMS of cells surrounding the tumors revealed predominantly G:C→T:A mutations characteristic of AFB 1 exposure. Importantly, 25% of all mutations were G→T in one trinucleotide context (CGC; the underlined G is the position of the mutation), which is also a hotspot mutation in human liver tumors whose incidence correlates with AFB 1 exposure. The technology proved sufficiently sensitive that the same distinctive spectrum was detected as early as 10 wk after dosing, well before evidence of neoplasia. Additionally, analysis of tumor tissue revealed a more complex pattern than observed in surrounding hepatocytes; tumor HRMS were a composite of the 10-wk spectrum and a more heterogeneous set of mutations that emerged during tumor outgrowth. We propose that the 10-wk HRMS reflects a short-term mutational response to AFB 1 , and, as such, is an early detection metric for AFB 1 -induced liver cancer in this mouse model that will be a useful tool to reconstruct the molecular etiology of human hepatocarcinogenesis. duplex sequencing | mycotoxins | cancer | mutagenesis | mouse model

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Section: Methodsmentioning

confidence: 99%

Mutational spectra of aflatoxin B ₁ in vivo establish biomarkers of exposure for human hepatocellular carcinoma

Chawanthayatham

Valentine

Fedeles

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

109

113

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“…This experimental system comprises λ-EG10-based transgenic C57BL/6 mice harboring tandem arrays of 80 copies of the bacterial gpt gene at a single site on chromosome 17. The model was specifically designed to facilitate the in vivo detection of point mutations by 6-thioguanine (6-TG) selection, and deletions up to 10 kb in length by selection based on sensitivity to P2 interference (Spi − ) (24). When phage DNA rescued from mouse tissues is introduced into appropriate Escherichia coli strains, both point mutations and large deletions can be efficiently detected (24).…”

mentioning

confidence: 99%

Mutagenic potency ofHelicobacter pyloriin the gastric mucosa of mice is determined by sex and duration of infection

Sheh

Lee

Masumura

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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Helicobacter pylori is a human carcinogen, but the mechanisms evoked in carcinogenesis during this chronic inflammatory disease remain incompletely characterized. We determined whether chronic H. pylori infection induced mutations in the gastric mucosa of male and female gpt delta C57BL/6 mice infected for 6 or 12 mo. Point mutations were increased in females infected for 12 mo. The mutation frequency in this group was 1.6-fold higher than in uninfected mice of both sexes (P < 0.05). A:T-to-G:C transitions and G:C-to-T:A transversions were 3.8 and 2.0 times, respectively, more frequent in this group than in controls. Both mutations are consistent with DNA damage induced by oxidative stress. No increase in the frequency of deletions was observed. Females had more severe gastric lesions than males at 6 mo postinfection (MPI; P < 0.05), but this difference was absent at 12 MPI. In all mice, infection significantly increased expression of IFNγ, IL-17, TNFα, and iNOS at 6 and 12 mo, as well as H. pylori-specific IgG1 levels at 12 MPI (P < 0.05) and IgG2c levels at 6 and 12 MPI (P < 0.01 and P < 0.001). At 12 MPI, IgG2c levels in infected females were higher than at 6 MPI (P < 0.05) and also than those in infected males at 12 MPI (P < 0.05). Intensity of responses was mediated by sex and duration of infection. Lower H. pylori colonization indicated a more robust host response in females than in males. Earlier onset of severe gastric lesions and proinflammatory, Th1-biased responses in female C57BL/6 mice may have promoted mutagenesis by exposing the stomach to prolonged oxidative stress.gpt delta mouse | Helicobacter | inflammation | mutagenesis | sexual dimorphism

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“…The transgenic mice called Mutamouse and Big Blue mouse, possessing bacterial lacZ and lacI genes, respectively, can be treated with chemicals or radiation, and the mutation target transgenes can then be recovered from the mouse cells into plaques of bacteriophage l (12,13). Nohmi et al (14) also established a new transgenic mouse carrying the bacterial gptD gene that can be recovered into bacteriophage l. This gptD assay system was adopted as the in vivo mutation assay in the OECD guidelines (15).…”

Section: Introduction: a Chronicle Of Methods In Mutation Researchmentioning

confidence: 99%

The Achievement of Shuttle Vector Techniques in Mammalian Cell Mutation Research

Yagi¹

2013

Genes and Environment

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Shuttle vector plasmids have made major contributions to the advancement of mutation research for the last two decades. I have been involved in the development of shuttle vector plasmids and their experimental protocols, and herein provide a chronicle of shuttle vector studies. In the late 1960s, in vitro mammalian cell culture became a common technique in cell biology. Geneticists established a method to detect gene mutation as 8-azaguanine or 6-thioguanine resistance after cells had been exposed to radiation or chemicals. The resistance of the cells was found to be due to a mutation of the hypoxanthine-guanine phosphoribosyl transferase gene; however, which base was changed in the gene remained di‹cult to determine until DNA sequencing techniques were developed. After the Sanger method of DNA sequencing became available to geneticists, the next issue was how to identify numerous base changes in mutants easily and rapidly. A breakthrough on this issue was the use of the shuttle vector plasmid pZ189, which was developed for practical applications by Seidman and colleagues. Along with the development of new molecular biology techniques such as polymerase chain reaction and automatic DNA sequencing, pZ189 has been modiˆed to several forms as adaptations to the new techniques. These shuttle vector plasmids remain useful tools to reveal what types of mutations are induced by newly identiˆed mutagens at the DNA sequence level. This article describes some of the contents of my JEMS award lecture in 2011.

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Other transgenic mutation assays: A new transgenic mouse mutagenesis test system using Spi− and 6-thioguanine selections

Cited by 207 publications

References 26 publications

Mutational spectra of aflatoxin B ₁ in vivo establish biomarkers of exposure for human hepatocellular carcinoma

Mutational spectra of aflatoxin B ₁ in vivo establish biomarkers of exposure for human hepatocellular carcinoma

Mutagenic potency ofHelicobacter pyloriin the gastric mucosa of mice is determined by sex and duration of infection

The Achievement of Shuttle Vector Techniques in Mammalian Cell Mutation Research

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Other transgenic mutation assays: A new transgenic mouse mutagenesis test system using Spi− and 6-thioguanine selections

Cited by 207 publications

References 26 publications

Mutational spectra of aflatoxin B 1 in vivo establish biomarkers of exposure for human hepatocellular carcinoma

Mutational spectra of aflatoxin B 1 in vivo establish biomarkers of exposure for human hepatocellular carcinoma

Mutagenic potency ofHelicobacter pyloriin the gastric mucosa of mice is determined by sex and duration of infection

The Achievement of Shuttle Vector Techniques in Mammalian Cell Mutation Research

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Mutational spectra of aflatoxin B ₁ in vivo establish biomarkers of exposure for human hepatocellular carcinoma

Mutational spectra of aflatoxin B ₁ in vivo establish biomarkers of exposure for human hepatocellular carcinoma