FLEx technology allows scientists to induce the expression of a mutated gene or a reporter gene at an appropriate time during the lifetime of the animal model. FLEx technology was invented by Prof. Chambon, Dr. Schnütgen and Dr. Ghyselinck at the Institut de Génétique et de Biologie Moléculaire et Cellulaire (France). ‍

Access to time- and tissue-restricted point mutant models 

This technique has become the gold standard for the generation of kinase-dead mutants and functional Knockouts. The mutant gene is induced in a temporal- and tissue-specific manner. Mutant gene expression is physiologically relevant and appropriate since the gene continues to be expressed from its endogenous locus.

The FLEx model:

• Bypasses potentially lethal phenotypes associated with the expression of the mutation
• Allows the researcher to analyze the effect of the mutated gene when the mouse is an adult
• Can reproduce a particular pathology that is triggered by a mutation and that normally manifests in adulthood
• Expresses the mutation from the endogenous locus and can therefore be regulated physiologically ‍

Read also:

• FLEx technology and optogenetics: Flipping the switch on gene expression with high spatial and temporal resolution
• genOway licenses the Flex technology rights to HHMI for the distribution of its AAV FLEX ‍

Access to monitoring of tissue-specific and temporally specific gene ablation 

FLEx technology can also create conditional mouse models for the express purpose of monitoring gene deletion.

This approach is often valuable when:

• No reliable antibody exists that can detect your target gene or quantify its deletion
• You are interested in monitoring the trafficking of gene-deleted cells
• You wish to monitor gene expression patterns ‍

How does it work?

This tool is based on the Cre-lox system.

Both loxP and lox511 are recognized by Cre recombinase, but lox511 sites can only recombine with other lox511 sites, not with loxP sites.

When the DNA sequence is flanked by lox sites in opposing orientations, the Cre will invert the sequence between the sites. If the DNA sequence is flanked by lox sites in the same orientation, the Cre will excise the sequence.

By combining the type, number, and orientation of lox sites that surround your genes of interest, a powerful FLEx tool can be created, tailored to your specific scientific needs.

References describing applications using FLEx technology:

Inducible Knockout: F. Schnütgen et al. Nature Biotech 2003. A directional strategy for monitoring Cre-mediated recombination at the cellular level in the mouse.

Gene trapping: F. Schnütgen et al. PNAS 2005. Genomewide production of multipurpose alleles for the functional analysis of the mouse genome.

Gene reporter switch: D. Atasoy et al. J Neuroscience 2008. A FLEX switch targets Channelrhodopsin-2 to multiple cell types for imaging and long-range circuit mapping.