Formation of macromolecular complexes and other effects of DNA treatment with diethyl and dimethyl sulfate: physico-chemical and electron microscopic studies
| Autor: | Z.O. Kubinski, G. Konopa, H. Kubinski, M. Fiandt |
|---|---|
| Rok vydání: | 1981 |
| Předmět: |
DNA
Bacterial Alkylating Agents Cancer Research Chemical Phenomena Sulfuric Acid Esters medicine.disease_cause Dimethyl sulfate chemistry.chemical_compound Escherichia coli medicine Molecule Centrifugation Cells Cultured Molecular mass Chemistry Physical Mutagenesis DNA General Medicine Sulfuric Acids Bacteriophage lambda Microscopy Electron Electrophoresis Biochemistry chemistry DNA Viral |
| Zdroj: | Carcinogenesis. 2:981-990 |
| ISSN: | 1460-2180 0143-3334 |
| DOI: | 10.1093/carcin/2.10.981 |
| Popis: | In vitro exposures of isolated DNA to one of the two carcinogenic and mutagenic chemicals, diethylsulfate or dimethylsulfate, induces several kinds of physicochemical and morphological alterations. These changes are detectable by a variety of independent techniques. A fraction of DNA treated briefly with either of these two chemicals moves during velocity centrifugation experiments less rapidly than the bulk of control DNA and more rapidly through gels during electrophoresis. This apparent decrease in size is paralleled by the formation of large DNA aggregates with mobilities indicating molecular weights several times that of the untreated, control DNA. The presence of a basic protein in the incubation mixture increases the rate of formation of such complexes. the tendency of the alkylated DNA to bind to both biological and non-biological materials is reflected in the increased attachment of DNA to columns built with methyl-esterified serum albumin and in its quantitative retention on nitrocellulose filters. DNA exposed to dimethylsulfate decreases its density in CsCl gradients. A mixture of two or more DNAs of different densities exposed to this chemical produces an u.v.-absorbing band which is found in such gradients at an intermediate density. If the alkylation reaction is carried out in the presence of a protein, a portion of DNA bands at a density intermediate between the density of DNA and that of the protein, even in the presence of an ionic detergent in the gradient. Under the electron microscope the alkylated DNA shows multiple single-strand breaks and peeling-off whiskers of denatured DNA. Aggregates of DNA molecules become visible upon further incubation of DNA with the alkylating agent. We suggest that the DNA-DNA and DNA- protein complexes play an important role in the process of carcinogenesis and mutagenesis. |
| Databáze: | OpenAIRE |
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