Flpe

Flpe refers to an enhanced version of the Flp recombinase enzyme derived from the yeast Saccharomyces cerevisiae. It recognizes and recombines DNA at FRT (flippase recognition target) sites, enabling precise, site-specific rearrangements in genomes.

Like Flp, Flpe is a serine recombinase that catalyzes recombination between two FRT sites. The outcome—excision, inversion, or translocation—depends on the relative orientation of the FRT sites and their genomic context. Flpe variants were engineered to maintain activity at higher temperatures, increasing efficiency in mammalian cells, where the native Flp enzyme is less active at 37°C.

Historically, the Flp-FRT system was developed as an alternative or complement to the Cre-loxP system for conditional mutagenesis. Flpe, often codon-optimized for mammalian expression, is commonly used in mouse genetics to create conditional alleles, remove selectable markers, or enable tissue-specific or temporally controlled recombination when paired with appropriate promoters. Flp recombinase is frequently used in conjunction with Cre recombinase in separate genomic loci to implement multi-step genetic modifications.

Limitations and considerations include varying recombination efficiency influenced by expression level, promoter choice, and chromatin context. Although Flpe is designed to minimize off-target activity at non-FRT sites, careful experimental design is required to avoid unintended rearrangements.

See also: FLP recombinase, FRT, Cre-loxP system.