Abstract
The application of a 32P-postlabeling assay for 7-methylguanines in DNA was studied either by labeling the imidazole ring-opened dinucleotide derivatives or by using strong-anion-exchange column chromatography for the adduct enrichment from normal nucleotides. Data showed that 7-methylguanines can be efficiently labeled as dinucleotides when in vitro methylated DNA was first imidazole ring-opened and then digested to the dinucleotide level with deoxyribonuclease I, snake venom phosphodiesterase, and prostatic acid phosphatase. When using ion exchange chromatography for the adduct enrichment, DNA was digested with micrococcal nuclease and spleen phosphodiesterase. Anion exchange chromatography was applied for 7-methylguanine measurements in white blood cell DNA of healthy nonsmokers (n = 17) and patients (n = 4) treated with the methylating drugs procarbazine and decarbazine. We found that the mean level of 7-methylguanine residues in nonsmokers was 2.5 per 10(7) nucleotides. The corresponding level in the patient samples immediately after the drug treatment was 57 per 10(7) nucleotides.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Fong L. Y., Jensen D. E., Magee P. N. DNA methyl-adduct dosimetry and O6-alkylguanine-DNA alkyl transferase activity determinations in rat mammary carcinogenesis by procarbazine and N-methylnitrosourea. Carcinogenesis. 1990 Mar;11(3):411–417. doi: 10.1093/carcin/11.3.411. [DOI] [PubMed] [Google Scholar]
- Gupta R. C., Earley K. 32P-adduct assay: comparative recoveries of structurally diverse DNA adducts in the various enhancement procedures. Carcinogenesis. 1988 Sep;9(9):1687–1693. doi: 10.1093/carcin/9.9.1687. [DOI] [PubMed] [Google Scholar]
- Hemminki K. Ring-opened 7-methylguanine nucleotides are resistant to nuclease P1 digestion and good substrates to polynucleotide kinase. Carcinogenesis. 1989 Sep;10(9):1761–1763. doi: 10.1093/carcin/10.9.1761. [DOI] [PubMed] [Google Scholar]
- Mustonen R., Försti A., Hietanen P., Hemminki K. Measurement by 32P-postlabelling of 7-methylguanine levels in white blood cell DNA of healthy individuals and cancer patients treated with dacarbazine and procarbazine. Human data and method development for 7-alkylguanines. Carcinogenesis. 1991 Aug;12(8):1423–1431. doi: 10.1093/carcin/12.8.1423. [DOI] [PubMed] [Google Scholar]
- Reddy M. V., Gupta R. C., Randerath E., Randerath K. 32P-postlabeling test for covalent DNA binding of chemicals in vivo: application to a variety of aromatic carcinogens and methylating agents. Carcinogenesis. 1984 Feb;5(2):231–243. doi: 10.1093/carcin/5.2.231. [DOI] [PubMed] [Google Scholar]
- Reddy M. V., Randerath K. Nuclease P1-mediated enhancement of sensitivity of 32P-postlabeling test for structurally diverse DNA adducts. Carcinogenesis. 1986 Sep;7(9):1543–1551. doi: 10.1093/carcin/7.9.1543. [DOI] [PubMed] [Google Scholar]
- Shields P. G., Povey A. C., Wilson V. L., Weston A., Harris C. C. Combined high-performance liquid chromatography/32P-postlabeling assay of N7-methyldeoxyguanosine. Cancer Res. 1990 Oct 15;50(20):6580–6584. [PubMed] [Google Scholar]
- Souliotis V. L., Boussiotis V. A., Pangalis G. A., Kyrtopoulos S. A. In vivo formation and repair of O6-methylguanine in human leukocyte DNA after intravenous exposure to dacarbazine. Carcinogenesis. 1991 Feb;12(2):285–288. doi: 10.1093/carcin/12.2.285. [DOI] [PubMed] [Google Scholar]
- Souliotis V. L., Kaila S., Boussiotis V. A., Pangalis G. A., Kyrtopoulos S. A. Accumulation of O6-methylguanine in human blood leukocyte DNA during exposure to procarbazine and its relationships with dose and repair. Cancer Res. 1990 May 1;50(9):2759–2764. [PubMed] [Google Scholar]
- Wilson V. L., Smith R. A., Autrup H., Krokan H., Musci D. E., Le N. N., Longoria J., Ziska D., Harris C. C. Genomic 5-methylcytosine determination by 32P-postlabeling analysis. Anal Biochem. 1986 Feb 1;152(2):275–284. doi: 10.1016/0003-2697(86)90409-4. [DOI] [PubMed] [Google Scholar]