Burnouf D. Y., Wagner J. E.
Kinetics of deoxy-CTP incorporation opposite a dG-C8-N-2-aminofluorene adduct by a high-fidelity DNA polymerase Article de journal
Dans: J Mol Biol, vol. 386, no. 4, p. 951-61, 2009, (1089-8638 (Electronic) Journal Article Research Support, Non-U.S. Gov't).
Résumé | BibTeX | Étiquettes: Adducts, Bacillus, Catalytic, Cytidine, Deoxyguanosine/*metabolism, DNA, DNA-Directed, Domain, DUMAS, Elements, Fluorenes/*metabolism, Guanine, Kinetics, Oligonucleotides/metabolism, Phosphorothioate, Polymerase/*metabolism, Specificity, stearothermophilus/enzymology, Substrate, Titrimetry, Triphosphate/*metabolism
@article{,
title = {Kinetics of deoxy-CTP incorporation opposite a dG-C8-N-2-aminofluorene adduct by a high-fidelity DNA polymerase},
author = { D. Y. Burnouf and J. E. Wagner},
year = {2009},
date = {2009-01-01},
journal = {J Mol Biol},
volume = {386},
number = {4},
pages = {951-61},
abstract = {The model carcinogen N-2-acetylaminofluorene covalently binds to the C8 position of guanine to form two adducts, the N-(2'-deoxyguanosine-8-yl)-aminofluorene (G-AF) and the N-2-(2'-deoxyguanosine-8-yl)-acetylaminofluorene (G-AAF). Although they are chemically closely related, their biological effects are strongly different and they are processed by different damage tolerance pathways. G-AF is bypassed by replicative and high-fidelity polymerases, while specialized polymerases ensure synthesis past of G-AAF. We used the DNA polymerase I fragment of a Bacillus stearothermophilus strain as a model for a high-fidelity polymerase to study the kinetics of incorporation of deoxy-CTP (dCTP) opposite a single G-AF. Pre-steady-state kinetic experiments revealed a drastic reduction in dCTP incorporation performed by the G-AF-modified ternary complex. Two populations of these ternary complexes were identified: (i) a minor productive fraction (20%) that readily incorporates dCTP opposite the G-AF adduct with a rate similar to that measured for the adduct-free ternary complexes and (ii) a major fraction of unproductive complexes (80%) that slowly evolve into productive ones. In the light of structural data, we suggest that this slow rate reflects the translocation of the modified base within the active site, from the pre-insertion site into the insertion site. By making this translocation rate limiting, the G-AF lesion reveals a novel kinetic step occurring after dNTP binding and before chemistry.},
note = {1089-8638 (Electronic)
Journal Article
Research Support, Non-U.S. Gov't},
keywords = {Adducts, Bacillus, Catalytic, Cytidine, Deoxyguanosine/*metabolism, DNA, DNA-Directed, Domain, DUMAS, Elements, Fluorenes/*metabolism, Guanine, Kinetics, Oligonucleotides/metabolism, Phosphorothioate, Polymerase/*metabolism, Specificity, stearothermophilus/enzymology, Substrate, Titrimetry, Triphosphate/*metabolism},
pubstate = {published},
tppubtype = {article}
}
Rihn B. H., Bottin M. C., Coulais C., Rouget R., Monhoven N., Baranowski W., Edorh A., Keith G.
Genotoxicity of 3-methylcholanthrene in liver of transgenic big Blue mice Article de journal
Dans: Environ Mol Mutagen, vol. 36, no. 4, p. 266-73, 2000, (0893-6692 Journal Article).
Résumé | BibTeX | Étiquettes: *Escherichia, Adducts, Animals, Bacterial, Base, C57BL, Cell, coli, Division/drug, DNA, effects, Gov't, Inbred, Liver/cytology/*drug, Methylcholanthrene/*toxicity, Mice, Mutagens/*toxicity, Mutation, Non-U.S., Organ, Primers, Proteins, Proteins/genetics, Repressor, Sequence, Support, transgenic, Weight
@article{,
title = {Genotoxicity of 3-methylcholanthrene in liver of transgenic big Blue mice},
author = { B. H. Rihn and M. C. Bottin and C. Coulais and R. Rouget and N. Monhoven and W. Baranowski and A. Edorh and G. Keith},
year = {2000},
date = {2000-01-01},
journal = {Environ Mol Mutagen},
volume = {36},
number = {4},
pages = {266-73},
abstract = {Transgenic mice provide a unique tool for studying the tissue specificity and mutagenic potential of chemicals. Because 3-methylcholanthrene (3MC) was found mutagenic in bacteria, clastogenic in bone marrow, and induces DNA adducts in animals, we were interested to determinine whether this xenobiotic provokes (1) cell proliferation, (2) transcriptional activity changes, (3) DNA adducts, and (4) hepatic mutations in transgenic Big Blue mice carrying the lambdaLIZ phage shuttle vector. Big Blue C57/Bl male mice were treated with a single intraperitoneal dose of 80 mg/kg 3MC for 1, 3, 6, 14, or 30 days. Cell proliferation was checked by 5-bromo-2-deoxyuridine labeling and immunohistochemical detection. The maximal increase of the mitotic index was evidenced after 3 days (2.9 times the control value; P < 0.01). The relative nucleus area, reflecting the transcriptional activity, was also the highest in the treated group after 3 days: 1.86 times the control value, on average (P < 0.01). Four major DNA adducts, determined according to the [(32)P]-postlabeling method, were evidenced in liver DNA of treated mice, 6 days after the treatment: the spot intensities increased in a time-dependent manner. The mutant frequency of liver DNA was the highest after 14 days: 20.3 +/- 2.9 x 10(-5) in the treated vs. 7.6 +/- 2.7 x 10(-5) in the control mice (P < 0.01). Sequencing of the lambda lacI mutant plaques showed mainly G:C --> T:A and C:G --> A:T transversions. In conclusion, 3MC at first induced nuclear enlargement and a slight increase of cell proliferation in liver, followed by parallel formation of DNA adducts and mutations. This study shows how transgenic models allow in vivo evaluation of mechanistically simultaneous endpoints.},
note = {0893-6692
Journal Article},
keywords = {*Escherichia, Adducts, Animals, Bacterial, Base, C57BL, Cell, coli, Division/drug, DNA, effects, Gov't, Inbred, Liver/cytology/*drug, Methylcholanthrene/*toxicity, Mice, Mutagens/*toxicity, Mutation, Non-U.S., Organ, Primers, Proteins, Proteins/genetics, Repressor, Sequence, Support, transgenic, Weight},
pubstate = {published},
tppubtype = {article}
}