The advent of transgenic technology has greatly fa-deamination-directed mutation at methylated cytocilitated the study of mutation in animals in vivo. sine bases. The second most common class of muta-The Big Blue mouse system, transgenic for the lacI tions is G:C r T:A transversions. A significant c
Mutational spectrum of dimethylnitrosamine in the liver of 3- and 6-week-old lacI transgenic mice
โ Scribed by Johan G. de Boer; Jon C. Mirsalis; Barry W. Glickman
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 49 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0893-6692
No coin nor oath required. For personal study only.
โฆ Synopsis
We determined the spectrum of mutations in the lacI gene in the liver of Big Blueเฎพ transgenic mice after exposure to five daily doses of 2 mg/kg dimethylnitrosamine (DMN) at 3 and 6 weeks of age. This dose has been reported to increase the mutant frequency 9-fold when the animals are 3 weeks old. The lacI mutations recovered when treated at 3 weeks consist of mainly G:C 3 A:T transitions, predominantly at non-CpG sites, and thus are consistent with mutagenesis by DMN. No increase in mutant frequency was reported when the mice were treated at 6 weeks of age. As we have previously shown that changes in mutational spectrum can be detected even when no statistically significant increase in mutant frequency is seen, we also examined the spectrum after treatment at 6 weeks. No changes from the spontaneous spectrum were detected. The comparison of the outcome of DMN treatment at 3 and 6 weeks confirms a change in metabolic activation, adduct removal, or mutation fixation between 3 and 6 weeks of age.
๐ SIMILAR VOLUMES
Big Blue ยฎ mice harbor a recoverable transgene in a lambda/LIZ shuttle vector. In the standard assay, in vivo mutations are measured in the bacterial lacI gene using a labor-intensive color plaque assay. Applying a simpler assay : Proc Natl Acad Sci USA 93:9073-9078], we measured mutations in the la
Transgenic mice are widely used to detect gene mutations in vivo induced by a variety of chemicals. It is known, however, that no mutagenicity of methyl methanesulfonate (MMS) is detected in epididymal sperm in various transgenic mice assays, although MMS induces the dominant lethal and specific loc
Trichloroethylene (TCE) is a multimedia environmental pollution that is carcinogenic in mouse liver. The ability of TCE to modulate DNA methylation and the expression of immediate-early protooncogenes was evaluated. Female B6C3F1 mice were administered 1000 mg/kg TCE by gavage 5 days/week and killed
The newborn mouse tumorigenicity assay, which reached 155.1 1 10 06 following a cumulative dose involves the treatment of animals during the first two of 49 mg ENU/kg body weight and 172.3 1 10 06 weeks after birth and monitoring tumor induction following a cumulative dose of 142 mg ENU/kg. after a