Effect of 2-chloroethylnitrosoureas on plasmid DNA including formation of strand breaks and interstrand cross-links

Chemico-biological Interactions
H V Vadi, D J Reed


Plasmid [3H]pBR 322 was incubated with various alkylating agents including chlorozotocin, N,N'-bis(2-chloroethyl)-N'-nitrosourea (BCNU), N-ethyl-N-nitrosourea (Enu) and dimethylsulfate (DMS). Formation of DNA strand breaks was followed by separation of the various forms of DNA on agarose gels and liquid scintillation counting of the bands. All alkylating agents examined were capable of rapidly producing strand breaks in time and concentration dependent fashion. Bands migrating as relaxed circular and supercoiled forms of the plasmid disappeared, and extensive alkylation resulted in formation of a band that migrated faster than the linear form of DNA. Electron microscopy of this band showed that it consisted of relaxed circles. Prolonged storage of alkylated plasmid resulted in fragmentation of the DNA, possibly due to strand scission at apurinic sites. A new neutral denaturation technique was developed, which allowed for the detection of DNA interstrand cross-links with minimal effects on other potentially labile sites of the alkylated DNA. The level of alkylation was quantitated by incubating [3H]pBR 322 with [2-chloroethyl-U-14C]chlorozotocin and was shown to be independent of DNA concentration but have a linear relationship ...Continue Reading


Jul 31, 2013·Neurologic Clinics·Rimas V Lukas, Martin Kelly Nicholas
May 1, 1989·Archives of Biochemistry and Biophysics·L C Leite, O Augusto
Nov 2, 2005·Bioorganic Chemistry·Anna Maria TimperioLello Zolla

Related Concepts

DNA Replication
DNA Restriction Enzymes
DNA, Bacterial
Alkalescens-Dispar Group
Electron Microscopy
Nitrogen Mustard Compounds
Nitrosourea Compounds

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