A versatile transgenic allele for mouse overexpression studies.

Area of Science:

• Genetics and Genomics
• Molecular Biology
• Transgenic Animal Models

Background:

• Gene overexpression in mice offers an alternative to loss-of-function studies for analyzing gene function in vivo.
• Existing methods for generating gain-of-function transgenic mouse models have limitations, including high costs and a lack of tunable expression levels.
• Targeted integration of transgenes is preferred over random integration for reliable model generation, but typically yields only one expression level.

Purpose of the Study:

• To develop a versatile and cost-effective overexpression allele for generating gain-of-function mouse models.
• To enable tunable transgene expression within a single mouse model for systematic gain-of-function studies.
• To correlate phenotype severity with transgene expression levels, facilitating the exploration of gene dosage effects.

Main Methods:

• Utilized PhiC31 integrase-targeted transgenesis for precise integration of overexpression constructs into neutral genomic loci.
• Incorporated Flp recombinase-mediated promoter switching and Cre recombinase activation for dynamic control of transgene expression.
• Developed a novel 'promoter-switch allele' system combining targeted transgenesis with recombination-based expression tuning.

Main Results:

• The promoter-switch allele system successfully couples targeted transgenesis with tunable transgene expression.
• This approach allows for the generation of multiple expression levels from a single targeted integration event.
• Enables direct correlation of phenotype severity with varying transgene expression levels within one mouse model.

Conclusions:

• The developed promoter-switch allele offers a versatile and cost-effective solution for gain-of-function studies in mice.
• This system overcomes limitations of previous methods by providing tunable gene expression and facilitating gene dosage analysis.
• The approach is amenable to systematic functional gene analysis, reducing animal and financial costs associated with generating multiple transgenic lines.