Breaks in genomic DNA and within the p53 gene are associated with hypomethylation in livers of folate/methyl-deficient rats.

Male weanling Fischer 344 rats were fed either a semipurified diet deficient in the methyl donors methionine, choline, and folic acid or a supplemented control diet for a period of 9 weeks. At intervals of 2, 5, and 7 days, 3 weeks, and 9 weeks after initiation of the respective diets, the relative level of DNA strand breaks and the degree of cytosine methylation were quantified in high molecular weight DNA and also within the p53 gene in liver samples from these rats. Genome-wide strand break accumulation was associated with progressive genomic hypomethylation and increased DNA methyltransferase activity. With the use of quantitative PCR as a gene-specific DNA strand break assay, unique DNA strand breaks were detected in exon 5 but not in exons 6-8 of the p53 gene, and were accompanied by significant p53 gene hypomethylation. DNA hypomethylation has been shown to alter the conformation and stability of the chromatin structure, rendering affected regions more accessible to DNA-damaging agents. To determine whether methylation status alters the sensitivity of DNA to strand breakage, DNA in isolated nuclei was methylated in vitro and exposed to endogenous calcium/magnesium-dependent endonuclease activated under defined conditions. The incidence of enzyme-induced DNA strand breaks was decreased significantly with increased DNA methylation. In nuclei isolated from livers of methyl-deficient rats, the hypomethylated DNA was found to be more sensitive to enzyme- and oxidant-induced DNA strand break induction. Taken together, these results provide evidence that DNA strand breaks are induced in high molecular weight DNA and also within the p53 gene in liver tissue from methyl-deficient rats. The increased incidence of these strand breaks in DNA from methyl-deficient rats may be related to alterations in chromatin accessibility associated with DNA hypomethylation.

[1]  R. Souhami,et al.  DNA damage by anticancer agents and its repair: mapping in cells at the subgene level with quantitative polymerase chain reaction. , 1994, Analytical biochemistry.

[2]  M. Kruszewski,et al.  DNA strand breakage, cytotoxicity and mutagenicity of hydrogen peroxide treatment at 4°C and 37°C in L5178Y sublines , 1994 .

[3]  Alexei G. Basnakian,et al.  A rapid and sensitive assay for the detection of DNA fragmentation during early phases of apoptosis , 1994, Nucleic Acids Res..

[4]  P. Jones,et al.  Ubiquitous and tenacious methylation of the CpG site in codon 248 of the p53 gene may explain its frequent appearance as a mutational hot spot in human cancer , 1994, Molecular and cellular biology.

[5]  W. Deppert.  The yin and yang of p53 in cellular proliferation. , 1994, Seminars in cancer biology.

[6]  K. Kohn,et al.  Effects of DNA methylation on topoisomerase I and II cleavage activities. , 1994, The Journal of biological chemistry.

[7]  M. Kastan,et al.  DNA strand breaks: the DNA template alterations that trigger p53-dependent DNA damage response pathways , 1994, Molecular and cellular biology.

[8]  J. Christman,et al.  Methyl deficiency, DNA methylation, and cancer: Studies on the reversibility of the effects of a lipotrope-deficient diet☆☆☆ , 1993 .

[9]  M. Vairapandi,et al.  Enzymic removal of 5-methylcytosine from DNA by a human DNA-glycosylase. , 1993, Nucleic acids research.

[10]  H. Shinozuka,et al.  Growth factor and receptor modulations in rat liver by choline-methionine deficiency☆☆☆ , 1993 .

[11]  A. E. Rogers,et al.  Diet and carcinogenesis. , 1993, Carcinogenesis.

[12]  D. Kaufman,et al.  Cell cycle control, DNA repair and initiation of carcinogenesis , 1993, FASEB journal : official publication of the Federation of American Societies for Experimental Biology.

[13]  S. Orrenius,et al.  Effects of glutathione and chelating agents on copper-mediated DNA oxidation: pro-oxidant and antioxidant properties of glutathione. , 1993, Archives of biochemistry and biophysics.

[14]  C. Wagner,et al.  DNA methylation in folate deficiency: use of CpG methylase. , 1993, Biochemical and biophysical research communications.

[15]  J. Locker,et al.  p53 mutations in hepatocellular carcinomas induced by a choline-devoid diet in male Fischer 344 rats. , 1993, Carcinogenesis.

[16]  R. Schneider,et al.  Structure of the rat p53 tumor suppressor gene. , 1993, Nucleic acids research.

[17]  M. Fritsche,et al.  Induction of nuclear accumulation of the tumor-suppressor protein p53 by DNA-damaging agents. , 1993, Oncogene.

[18]  S. C. Garner,et al.  Accumulation of 1,2-sn-diradylglycerol with increased membrane-associated protein kinase C may be the mechanism for spontaneous hepatocarcinogenesis in choline-deficient rats. , 1993, The Journal of biological chemistry.

[19]  Gewirtz Da.  DNA damage, gene expression, growth arrest and cell death. , 1993 .

[20]  D. Gewirtz.  DNA damage, gene expression, growth arrest and cell death. , 1993, Oncology research.

[21]  Peter A. Jones,et al.  High frequency mutagenesis by a DNA methyltransferase , 1992, Cell.

[22]  S. J. James,et al.  Alterations in nucleotide pools in rats fed diets deficient in choline, methionine and/or folic acid. , 1992, Carcinogenesis.

[23]  L. Poirier,et al.  Methyl groups in carcinogenesis: effects on DNA methylation and gene expression. , 1992, Cancer research.

[24]  Peter A. Jones,et al.  Methylation, mutation and cancer , 1992, BioEssays : news and reviews in molecular, cellular and developmental biology.

[25]  A. Bird,et al.  Transcriptional repression by methylation of CpG , 1992, Journal of Cell Science.

[26]  A. Bird,et al.  DNA methylation and chromatin structure , 1991, FEBS letters.

[27]  A. Basnakian,et al.  Nuclear topoisomerase I and DNase activities in rat diethylnitrosamine-induced hepatoma, in regenerating and fetal liver. , 1991, Biochemistry international.

[28]  Steven S. Smith.  DNA methylation in eukaryotic chromosome stability , 1991, Molecular carcinogenesis.

[29]  W. Morgan,et al.  Morphological transformation of 10T1/2 mouse embryo cells can be initiated by DNA double‐strand breaks alone , 1991, Molecular carcinogenesis.

[30]  R. Hoffman.  Unbalanced transmethylation and the perturbation of the differentiated state leading to cancer , 1990, BioEssays : news and reviews in molecular, cellular and developmental biology.

[31]  Robert L. Tanguay,et al.  A quantitative HpaII-PCR assay to measure methylation of DNA from a small number of cells. , 1990, Nucleic acids research.

[32]  A. Riches,et al.  Oncogenic transformation of murine C3H 10T1/2 cells resulting from DNA double-strand breaks induced by a restriction endonuclease. , 1989, British Journal of Cancer.

[33]  S. Henning,et al.  Hepatic content of S-adenosylmethionine, S-adenosylhomocysteine and glutathione in rats receiving treatments modulating methyl donor availability. , 1989, The Journal of nutrition.

[34]  A. Bird,et al.  Specific protection of methylated CpGs in mammalian nuclei , 1989, Cell.

[35]  S. J. James,et al.  Diet-induced DNA damage and altered nucleotide metabolism in lymphocytes from methyl-donor-deficient rats. , 1989, Carcinogenesis.

[36]  S. Zeisel,et al.  Effect of choline deficiency on S-adenosylmethionine and methionine concentrations in rat liver. , 1989, The Biochemical journal.

[37]  J. Locker,et al.  c-myc gene amplification during hepatocarcinogenesis by a choline-devoid diet. , 1989, Proceedings of the National Academy of Sciences of the United States of America.

[38]  G. Georgiev,et al.  Inhibition of transcription in eukaryotic cells by X-irradiation: relation to the loss of topological constraint in closed DNA loops. , 1988, Nucleic acids research.

[39]  L. Poirier,et al.  c-H-ras and c-K-ras gene hypomethylation in the livers and hepatomas of rats fed methyl-deficient, amino acid-defined diets. , 1988, Carcinogenesis.

[40]  Y. Wataya,et al.  Deoxyribonucleoside-triphosphate imbalance death: deoxyadenosine-induced dNTP imbalance and DNA double strand breaks in mouse FM3A cells and the mechanism of cell death. , 1987, Biochemical and biophysical research communications.

[41]  M. Szyf,et al.  Biological role of DNA methylation: sequence-specific single-strand breaks associated with hypomethylation of GATC sites in Escherichia coli DNA , 1986, Journal of bacteriology.

[42]  T. Rushmore,et al.  A choline-devoid diet, carcinogenic in the rat, induces DNA damage and repair. , 1986, Carcinogenesis.

[43]  Howard Cedar,et al.  DNA methylation affects the formation of active chromatin , 1986, Cell.

[44]  P. Jones,et al.  Effects of DNA binding proteins on DNA methylation in vitro. , 1985, Biochemistry.

[45]  T. Rushmore,et al.  Rapid lipid peroxidation in the nuclear fraction of rat liver induced by a diet deficient in choline and methionine. , 1984, Cancer letters.

[46]  E. Farber,et al.  The induction of liver cancer by dietary deficiency of choline and methionine without added carcinogens. , 1984, Carcinogenesis.

[47]  K. L. Hoover,et al.  Hepatocarcinogenesis in rats fed methyl-deficient, amino acid-defined diets. , 1983, Carcinogenesis.

[48]  L. Poirier,et al.  Tissue levels of S-adenosylmethionine and S-adenosylhomocysteine in rats fed methyl-deficient, amino acid-defined diets for one to five weeks. , 1983, Carcinogenesis.

[49]  J. Hulla,et al.  Structure of the rat p 53 tumor suppressor gene , 2022 .