FLP-FRT recombination

[2][3] In yeast, this enzyme corrects decreases in 2 μ plasmid copy number caused by rare missegregation events.

[4] Senecoff et al. (1987) investigated how nucleotide substitutions within the FRT affected the efficacy of the FLP-mediated recombination.

The authors induced base substitutions in either one or both of the FRT sites and tested the concentration of FLP required to observe site-specific recombinations.

[7] This family of recombinases performs its function via a type IB topoisomerase mechanism causing the recombination of two separate strands of DNA.

This pentad is made up of a lysine (Lysβ), two arginines (Arg I and II), a histidine (His-II), and a histidine/tryptophan (His/Trp-III) that comprises a mandatory and highly conserved constellation of residues for the active site of Flp and Cre (along with other IB topiosomerases).

However, due to patents and restrictions on the use of Cre-Lox recombination, great interest was taken to produce a more thermostable FLP-FRT cassette.

The E. coli were grown on arabinose plates at 37 °C and 40 °C, and if recombination occurred, the lacZ expression would be attenuated, and the colonies would appear white.

Genetic mosaicism occurs within an organism when similar cell types express different phenotypes due to dissimilar genotypes at specific loci.

This process will continue until the FLP proteins fall below the required concentrations resulting in cells within an organism possessing different genotypes.

[9][10] Before the publication of Dymecki et al. (1998), Cre recombinase had been used for cell-fate mapping of neuronal progenitors in mice using the En2 promoter.

The authors of Frickenhaus et al. (2015) had a two-fold objective: characterize and compare the efficacy of Flp recombinase "knock-out" to Cre recombinase "knock-out" and RNAi knockdown and reveal the function of cabeza (caz), the fly ortholog to FUS, in the neurons and muscle tissue of D. melanogaster.

[12] The authors conclude that the Flp recombinase "knock-out" tool is more effective than both RNAi and Cre recombinase for the purpose of knocking out specific genes in specific tissues or cell lines due to the lack of the leaky expression seen in both the Cre protein and the RNAi transcript.

[13] When these embryoes reached adulthood, they were mated with a wild type strain, and the resulting clutches had significantly less progeny that expressed the EGFP in the muscle tissue (0-4%).

[14] The authors of Rao et al. (2010) utilized the FLP recombinase tool for the production of a highly efficient phytosensors.

When the plants were exposed to heat-shock, FLP-induction led to the excision of the FRT-flanked vector, effectively moving the GUS gene directly downstream of the CaMV 35S promoter.

The activation of GUS led to the leaves of the plants to change from green to blue; thus, the phytosensor effectively reported stress to the model system!