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Ligand-activated site-specific recombination in mice
1Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université Louis Pasteur, Collège de France, C.U. de Strasbourg, France.
Summary
Scientists developed a tamoxifen-inducible Cre-ERT system for conditional gene targeting in mice. This new tool enables precise control over somatic mutations, advancing knockout phenotype analysis.
Area of Science:
- Genetics
- Molecular Biology
- Developmental Biology
Background:
- Conventional gene targeting in mice lacks temporal and tissue specificity for somatic mutations.
- Analyzing certain knockout phenotypes is challenging with existing genetic tools.
Purpose of the Study:
- To develop a conditional site-specific recombination system in mice.
- To enable temporal and tissue-specific gene manipulation using a novel Cre/lox system.
Main Methods:
- Fusion of Cre recombinase with a mutated human estrogen receptor ligand-binding domain (ER) to create tamoxifen-dependent Cre-ERT.
- Generation of transgenic mice expressing Cre-ERT under a cytomegalovirus promoter.
- Induction of gene excision in loxP-flanked genes via tamoxifen administration.
Main Results:
- Tamoxifen administration successfully induced site-specific recombination (gene excision) in transgenic mice.
- No significant gene excision was observed in untreated control animals.
- The Cre-ERT system demonstrated tamoxifen-dependent activity, independent of estradiol.
Conclusions:
- The novel tamoxifen-dependent Cre-ERT system provides conditional site-specific recombination in mice.
- This technology overcomes limitations of conventional gene targeting for studying gene function.
- It facilitates the analysis of previously inaccessible knockout phenotypes.