title: Role of p53 in the progression from ochratoxin A-induced DNA damage to gene mutations in the kidneys of mice.
abstract: Carcinogenic doses of ochratoxin A (OTA) cause increases of mutant frequencies (MFs) of the red/gam gene (Spi(-)) in the kidneys of p53-deficient gpt delta mice, but not in p53-proficient mice. Here, we investigated the role of p53 in the progression from OTA-induced DNA damage to gene mutations. To this end, p53-proficient and -deficient mice were administered 5 mg/kg OTA for 3 days or 4 weeks by gavage. After 3 days of administration, comet assays were performed and there were no differences in the degrees of OTA-induced DNA damage between p53-proficient and -deficient mice. However, the frequencies of γ-H2AX-positive tubular epithelial cells in p53-deficient mice were significantly higher than those in p53-proficient mice, implying that p53 inhibited the progression from DNA damage to DNA double-strand breaks (DSBs). Evaluation of global gene expression and relevant mRNA/protein expression levels demonstrated that OTA increased the expression of Cdkn1a, which encodes the p21 protein, in p53-proficient mice, but not in p53-deficient mice. Moreover, in p53-deficient mice, mRNA levels of cell cycle progression and DSB repair (homologous recombination repair [HR])-related genes were significantly increased. Thus, G1/S arrest due to activation of the p53/p21 pathway may contribute to the prevention of DSBs in p53-proficient mice. In addition, single base deletions/insertions/substitutions were predominant, possibly due to HR. Overall, these results suggested that OTA induced DSBs at the carcinogenic target site in mice and that p53/p21-mediated cell cycle control prevented an increase in the formation of DSBs, leading to gene mutations.
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Ken
authors: K
authors: Kuroda
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Daisuke
authors: D
authors: Hibi
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Yuji
authors: Y
authors: Ishii
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Yuh
authors: Y
authors: Yokoo
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Shinji
authors: S
authors: Takasu
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Aki
authors: A
authors: Kijima
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Kohei
authors: K
authors: Matsushita
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Ken-ichi
authors: K
authors: Masumura
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Yukio
authors: Y
authors: Kodama
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Tokuma
authors: T
authors: Yanai
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Hiroki
authors: H
authors: Sakai
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Takehiko
authors: T
authors: Nohmi
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan.
authors: Kumiko
authors: K
authors: Ogawa
authors: *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan *Division of Pathology, Division of Genetics and Mutagenesis, Division of Toxicology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193 and Biological Safety Research Center, National Institute of Health Sciences, Tokyo 158-8501, Japan umemura@nihs.go.jp.
authors: Takashi
authors: T
authors: Umemura
mesh_terms: D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D020552:Comet Assay; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D004269:DNA, Bacterial / Q000235:genetics; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000235:genetics; D059585:G1 Phase Cell Cycle Checkpoints; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation; D006657:Histones / Q000378:metabolism; D007150:Immunohistochemistry; D007668:Kidney / Q000378:metabolism* / Q000473:pathology; D007680:Kidney Neoplasms / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation; D009793:Ochratoxins; D020411:Oligonucleotide Array Sequence Analysis; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D004269:DNA, Bacterial; D006657:Histones; D009793:Ochratoxins; D016159:Tumor Suppressor Protein p53; C493957:Cdkn1a protein, mouse; C025589:ochratoxin A; C475961:gamma-H2AX protein, mouse
keywords: DNA damage; gene mutation; ochratoxin A; p53