© 1994 Oxford University Press
research-article |
Base-specific arrest of in vitro DNA replication by carcinogenic chromium: relationship to DNA interstrand crosslinking
Department of Pharmacology, The George Washington University, Medical Center 2300 Eye Street NW.Washington, DC 20037, USA
1To whom correspondence should be addressed
We have previously shown that trivalent chromium can bind to purified DNA and form lesions capable of obstructing DNA replication in vitro. Trivalent chromium is not, however, carcinogenic to humans. Rather, it is the end product of the intracellular reduction of hexavalent chromium, which is carcinogenic. The process of chromiwn reduction yields several reactive intermediates which may also interact with DNA, perhaps producing different lesions than those generated when trivalent chromium binds DNA. The present study was undertaken to determine whether the treatment of DNA with hexavalent chromium in the presence of ascorbate (the Intracellular reductant responsible for most in vivo chromium reduction), would also generate DNA lesions capable of obstructing replica tion. Using increasing chromium concentrations and a constant ascorbate:chromlum ratio of 0.5:1 to generate biologically relevant adduct levels, a DNA polymerase arrest assay revealed that polymerase arresting lesions were formed and were indistinguishable from those generated by trivalent chromium, in that the most prominent arrests sites were one base upstream of guanine residues on the template strand. Measurement of the amount of chromium bound to template DNA in relation to the number of arrests demonstrated that only a subset (18.5%) of the chromium adducts were capable of causing polymerase arrest. Arrest assays performed with increasing ratios of ascorbate to chromium showed that high ratios (
5:1) resulted in decreased polymerase arrests. DNA Interstrand crosslinks in the arrest assay template were detected by renaturing agarose gel electrophoresis, and were shown to decrease markedly with increasing ascorbate to chromium ratios, whereas chromium binding levels remained unchanged. These results strongly implicate DNA interstrand crosslinks as the polymerase arresting lesion. The present study confirms and extends our previous study with trivalent chromium, and suggests that while the initial chemical nature of the DNA lesions formed by either trivalent chromium or reductive intennediates of hexavalent chromium may differ, their effect on DNA replication is the same.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  A. J. Lee, N. J. Hodges, and J. K. Chipman Interindividual Variability in Response to Sodium Dichromate-Induced Oxidative DNA Damage: Role of the Ser326Cys Polymorphism in the DNA-Repair Protein of 8-Oxo-7,8-Dihydro-2'-Deoxyguanosine DNA Glycosylase 1 Cancer Epidemiol. Biomarkers Prev., February 1, 2005; 14(2): 497 - 505. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Ha, S. Ceryak, and S. R. Patierno Generation of S phase-dependent DNA double-strand breaks by Cr(VI) exposure: involvement of ATM in Cr(VI) induction of {gamma}-H2AX Carcinogenesis, November 1, 2004; 25(11): 2265 - 2274. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Reynolds, E. Peterson, G. Quievryn, and A. Zhitkovich Human Nucleotide Excision Repair Efficiently Removes Chromium-DNA Phosphate Adducts and Protects Cells against Chromate Toxicity J. Biol. Chem., July 16, 2004; 279(29): 30419 - 30424. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Ha, S. Ceryak, and S. R. Patierno Chromium (VI) Activates Ataxia Telangiectasia Mutated (ATM) Protein. REQUIREMENT OF ATM FOR BOTH APOPTOSIS AND RECOVERY FROM TERMINAL GROWTH ARREST J. Biol. Chem., May 9, 2003; 278(20): 17885 - 17894. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M.G. Medeiros, A.S. Rodrigues, M.C. Batoreu, A. Laires, J. Rueff, and A. Zhitkovich Elevated levels of DNA-protein crosslinks and micronuclei in peripheral lymphocytes of tannery workers exposed to trivalent chromium Mutagenesis, January 1, 2003; 18(1): 19 - 24. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N.J. Hodges and J.K. Chipman Down-regulation of the DNA-repair endonuclease 8-oxo-guanine DNA glycosylase 1 (hOGG1) by sodium dichromate in cultured human A549 lung carcinoma cells Carcinogenesis, January 1, 2002; 23(1): 55 - 60. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N.J. Hodges, B. Adam, A.J. Lee, H.J. Cross, and J.K. Chipman Induction of DNA-strand breaks in human peripheral blood lymphocytes and A549 lung cells by sodium dichromate: association with 8-oxo-2-deoxyguanosine formation and inter-individual variability Mutagenesis, November 1, 2001; 16(6): 467 - 474. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. E. Pritchard, S. Ceryak, L. Ha, J. L. Fornsaglio, S. K. Hartman, T. J. O'Brien, and S. R. Patierno Mechanism of Apoptosis and Determination of Cellular Fate in Chromium(VI)-exposed Populations of Telomerase-immortalized Human Fibroblasts Cell Growth Differ., October 1, 2001; 12(10): 487 - 496. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. E. Pritchard, J. Singh, D. L. Carlisle, and S. R. Patierno Cyclosporin A inhibits chromium(VI)-induced apoptosis and mitochondrial cytochrome c release and restores clonogenic survival in CHO cells Carcinogenesis, November 1, 2000; 21(11): 2027 - 2033. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. P. Waalkes, D. A. Fox, J. C. States, S. R. Patierno, and M. J. McCabe Jr. Metals and Disorders of Cell Accumulation: Modulation of Apoptosis and Cell Proliferation Toxicol. Sci., August 1, 2000; 56(2): 255 - 261. [Full Text] [PDF]
|
|
|
|
|
|
D. L. Carlisle, D. E. Pritchard, J. Singh, B. M. Owens, L. J. Blankenship, J. M. Orenstein, and S. R. Patierno Apoptosis and P53 Induction in Human Lung Fibroblasts Exposed to Chromium (VI): Effect of Ascorbate and Tocopherol Toxicol. Sci., May 1, 2000; 55(1): 60 - 68. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Arakawa, R. Ahmad, M. Naoui, and H.-A. Tajmir-Riahi A Comparative Study of Calf Thymus DNA Binding to Cr(III) and Cr(VI) Ions. EVIDENCE FOR THE GUANINE N-7-CHROMIUM-PHOSPHATE CHELATE FORMATION J. Biol. Chem., March 31, 2000; 275(14): 10150 - 10153. [Abstract] [Full Text] [PDF]
|
|