Related Experiment Videos
Targeted oncogene activation by site-specific recombination in transgenic mice
1Laboratory of Mammalian Genes and Development, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
Abstract:
An efficient and accurate method for controlled in vivo transgene modulation by site-directed recombination is described. Seven transgenic mouse founder lines were produced carrying the murine lens-specific alpha A-crystallin promoter and the simian virus 40 large tumor-antigen gene sequence, separated by a 1.3-kilobase-pair Stop sequence that contains elements preventing expression of the large tumor-antigen gene and Cre recombinase recognition sites. Progeny from two of these lines were mated with transgenic mice expressing the Cre recombinase under control of either the murine alpha A-crystallin promoter or the human cytomegalovirus promoter. All double-transgenic offspring developed lens tumors. Subsequent analysis confirmed that tumor formation resulted from large tumor-antigen activation via site-specific, Cre-mediated deletion of Stop sequences.
Insights
Researchers developed a method for controlled in vivo transgene modulation using site-directed recombination. This technique successfully activated the simian virus 40 large tumor-antigen gene in double-transgenic mice, leading to lens tumor formation.
Area of Science:
- Molecular Biology
- Genetics
- Oncology
Background:
- Controlled gene expression is crucial for studying gene function and disease mechanisms.
- Site-directed recombination offers a precise method for genetic manipulation.
- Previous methods lacked efficiency or accuracy for in vivo transgene modulation.
Purpose of the Study:
- To establish an efficient and accurate method for controlled in vivo transgene modulation.
- To demonstrate the utility of site-directed recombination for activating specific genes in vivo.
- To investigate the role of simian virus 40 large tumor-antigen in lens tumor formation.
Main Methods:
- Generation of transgenic mouse lines carrying a regulatable simian virus 40 large tumor-antigen (SV40-TAg) gene.
- Design of a Stop sequence containing Cre recombinase recognition sites to control SV40-TAg expression.
- Breeding of transgenic mice with Cre-expressing mice under tissue-specific or strong promoters.
- Induction of recombination and subsequent gene activation in double-transgenic offspring.
Main Results:
- Seven transgenic mouse founder lines were successfully generated.
- Double-transgenic offspring exhibited lens-specific tumor formation.
- Tumor development was directly correlated with Cre-mediated deletion of the Stop sequence.
- Activation of the SV40-TAg gene was confirmed as the cause of tumor formation.
Conclusions:
- Site-directed recombination provides a powerful tool for controlled in vivo transgene modulation.
- The developed method enables precise temporal and spatial control of gene expression.
- This system can be utilized to study oncogene activation and tumor development in vivo.
- The findings have implications for cancer research and the development of gene therapy strategies.