Studies on histones and non-histone proteins from rats treated with dimethylnitrosamine

Galbraith, A.I.; Itzhaki, Ruth F.

doi:10.1016/0009-2797(79)90171-6

Cited by 4 publications

(1 citation statement)

References 28 publications

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“…The ma.jority of the DNA adducts (70%) are removed within the first 24 hr, and 10% of the adducts persist for more than 30 days. Adduct formation to histone H3 takes longer to peak, repair (or protein replacement) occurs more slowly [other studies (15) have shown that histones containing small adducts are not turned over but that the adducts are removed; the mechanisms for dealing with large adducts (16,17) have not yet been defined], and adduct removal approaches completion. As with DNA, 7-BMBA adducts to serum albumin are rapidly lost.…”

Section: Isolation Of Hemoglobin and Albuminmentioning

confidence: 99%

Application of HPLC to the isolation of molecular targets in dosimetry studies.

Balhorn¹,

Mazrimas²,

Corzett³

1985

Environ Health Perspect

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High-performance liquid chromatography (HPLC) methods are described which permit the rapid isolation of multiple target macromolecules from the tissues of animals exposed to chemical mutagens. DNA and selected chromosomal proteins are isolated in a simple two step separation scheme. Isolated nuclei are dissolved in 3 M guanidine hydrochloride and the DNA and chromosomal proteins separated on a TSK 3000 SW column. The DNA peak is retained for analysis and the chromatin proteins are dialyzed, lyophylized, and rechromatographed on a PRP-1 column to separate individual histones. Hemoglobin and albumin, two proteins that may prove useful for monitoring mutagen exposure, are isolated from 100 ,L of blood by HPLC on a Poly Cat A cation exchange column.Using this approach, we have monitored the kinetics and dose response of adduct formation (and repair) to DNA, histone, hemoglobin and albumin in mice exposed to 7-bromomethylbenzanthracene and benzo [a]pyrene. The results of these studies are described and briefly discussed. Experiments with other mutagens demonstrate the limits to which DNA adduct quantification may be pushed using radioisotopes. Exposures to very high specific activity (200 Ci/mmole) benzo(a)pyrene have allowed DNA adduct quantification down to a few adducts per cell.

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Section: Isolation Of Hemoglobin and Albuminmentioning

confidence: 99%

Application of HPLC to the isolation of molecular targets in dosimetry studies.

Balhorn¹,

Mazrimas²,

Corzett³

1985

Environ Health Perspect

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Chain length heterogeneity of nucleosomal DNA in mouse liver after dimethylnitrosamine administration

Näslund

Decken

1981

Arch Toxicol

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The effect of dimethylnitrosamine on the nucleosomal structure of mouse liver chromatin was studied. After a single oral dose of dimethylnitrosamine (2-75 mg/kg body weight 45 min before sacrifice) liver nuclei were isolated and incubated with micrococcus nuclease. Nucleosomes were separated on sucrose density gradients. There were no differences in nucleosomal sedimentation velocities between preparations from control and dimethylnitrosamine treated animals. The supernatant obtained after centrifugation of the lysed nuclei (2 min at 4,000 gav) and nucleosomal peak fractions were used for isolation of DNA. DNA was heat denatured in 7 M urea or formamide. After electrophoresis on polyacrylamide gels areas under mononucleosomal DNA and smaller fragments were measured and compared with the total DNA area. The increase in DNA fragmentation was dimethylnitrosamine dose response dependent. When expressed as per cent of controls it amounted to 106% for 2 mg; 115% for 10 mg; 127% for 25 mg; 164% for 75 mg dimethylnitrosamine/kg body weight. A good correlation between mobility and log of chain length of phi chi 174 RF DNA-Hae III digest was obtained in nondenaturing 5% polyacrylamide gels and denaturing non-aqueous formamide polyacrylamide gels but not in 12% polyacrylamide gels containing 7 M urea. DNA of mononucleosomal peak fractions contained 200 and that of dinucleosomal peak fractions 400 nucleotides. Fragmentation of DNA was closely related to in vivo dimethylnitrosamine treatment but was not detected in measurements of protein-DNA complexes in the chromatin. It was disclosed on denaturation of DNA followed by polyacrylamide gel electrophoresis.

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N-nitroso compound exposure-associated transcriptomic profiles are indicative of an increased risk for colorectal cancer

et al. 2011

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Endogenous formation of N-nitroso compounds (NOCs), which are known animal carcinogens, could contribute to human carcinogenesis but definitive evidence is still lacking. To investigate the relevance of NOCs in human colorectal cancer (CRC) development, we analyzed whole genome gene expression modifications in human colon biopsies in relation to fecal NOC exposure. We had a particular interest in patients suffering from intestinal inflammation as this may stimulate endogenous NOC formation, and consequently predispose to CRC risk. Inflammatory bowel disease (IBD) patients diagnosed with ulcerative colitis and irritable bowel syndrome patients without inflammation, serving as controls, were therefore recruited. Fecal NOC were demonstrated in the majority of subjects. By associating gene expression levels of all subjects to fecal NOC levels, we identified a NOC exposure-associated transcriptomic response that suggests that physiological NOC concentrations may potentially induce genotoxic responses and chromatin modifications in human colon tissue, both of which are linked to carcinogenicity. In a network analysis, chromatin modifications were linked to 11 significantly modulated histone genes, pointing towards a possible epigenetic mechanism that may be relevant in comprehending NOC-induced carcinogenesis. In addition, pro-inflammatory transcriptomic modifications were identified in visually non-inflamed regions of the IBD colon. However, fecal NOC levels were slightly but not significantly increased in IBD patients, suggesting that inflammation did not strongly stimulate NOC formation. We conclude that NOC exposure is associated with gene expression modifications in the human colon that may suggest a potential role of these compounds in CRC development.

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Studies on histones and non-histone proteins from rats treated with dimethylnitrosamine

Cited by 4 publications

References 28 publications

Application of HPLC to the isolation of molecular targets in dosimetry studies.

Application of HPLC to the isolation of molecular targets in dosimetry studies.

Chain length heterogeneity of nucleosomal DNA in mouse liver after dimethylnitrosamine administration

N-nitroso compound exposure-associated transcriptomic profiles are indicative of an increased risk for colorectal cancer

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