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Published on: February 24, 2014
Background mutations and polymorphisms in lacZ-plasmid transgenic mice
M E Dollé1, W K Snyder, N J van Orsouw
1Institute for Drug Development, Cancer Therapy and Research Center, San Antonio, Texas 78229, USA. mdolle@saci.org
Environmental and Molecular Mutagenesis
|October 26, 1999
Summary
Investigating the lacZ-plasmid transgenic mouse model revealed artifactual mutations. These artifacts, mainly from star activity during plasmid recovery, occur at a frequency of 1.3 x 10(-5).
Area of Science:
- Genetics
- Molecular Biology
- Toxicology
Background:
- Transgenic animal models with reporter genes are crucial for measuring in vivo mutant frequencies.
- The lacZ-plasmid model excels at detecting large genomic rearrangements, unlike bacteriophage lambda systems.
Purpose of the Study:
- To investigate background mutant frequencies and spectra in the lacZ-plasmid transgenic mouse model.
- To identify and quantify sources of artifactual mutations within this model system.
Main Methods:
- Analysis of mutant frequencies and spectra in lacZ-plasmid transgenic mice.
- Investigation of host cell mutations (galE, galK, galT) contributing to background.
- Assessment of plasmid excision procedures, including HindIII restriction enzyme activity.
Main Results:
- A subset of mutants (~1.3 x 10^-5) are likely artifacts, independent of true mutation frequency.
- Host cell mutations (galactose-insensitive) contribute a small fraction to the background.
- Star activity during HindIII digestion is the largest contributor to background artifacts (~1.1 x 10^-5).
- Ten polymorphic sites were identified within the lacZ-plasmid cluster in founder line 60.
Conclusions:
- The lacZ-plasmid transgenic mouse model is sensitive to large rearrangements but susceptible to artifacts.
- Star activity during DNA recovery is a significant source of background mutations.
- Understanding these artifacts is crucial for accurate in vivo mutation frequency assessment.
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