Floxed
Encyclopedia
In genetics, floxed is used to describe the sandwiching of a DNA
sequence between two lox P
sites,and is a contraction of the phrase "flanked by LoxP". Recombination between LoxP sites is catalysed by Cre recombinase
. Floxing a gene allows it to be deleted (knocked out), translocated or inverted.
Floxed genes can also be used to produce organ-specific knockouts. For example, using the Cre recombinase
with the alpha-myosin heavy chain promoter causes the floxed gene to be inactivated in the heart alone. Further, these knockouts can be inducible. In several mouse studies Tamoxifen is used to induce the Cre recombinase
; in this case Cre is under control of the mouse estrogen receptor (Mer) in a MerCreMer system. Tamoxifen antagonizes the Mer to activate Cre recombinase allowing it to act on the floxed gene.
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
sequence between two lox P
Cre-Lox recombination
Cre-Lox recombination is a special type of site-specific recombination developed by Dr. Brian Sauer initially for use in activating gene expression in mammalian cell lines and transgenic mice . Subsequently, the laboratory of Dr...
sites,and is a contraction of the phrase "flanked by LoxP". Recombination between LoxP sites is catalysed by Cre recombinase
Cre recombinase
Cre recombinase, often abbreviated to Cre, is a Type I topoisomerase from P1 bacteriophage that catalyzes site-specific recombination of DNA between loxP sites. The enzyme does not require any energy cofactors and Cre-mediated recombination quickly reaches equilibrium between substrate and reaction...
. Floxing a gene allows it to be deleted (knocked out), translocated or inverted.
Floxed genes can also be used to produce organ-specific knockouts. For example, using the Cre recombinase
Cre recombinase
Cre recombinase, often abbreviated to Cre, is a Type I topoisomerase from P1 bacteriophage that catalyzes site-specific recombination of DNA between loxP sites. The enzyme does not require any energy cofactors and Cre-mediated recombination quickly reaches equilibrium between substrate and reaction...
with the alpha-myosin heavy chain promoter causes the floxed gene to be inactivated in the heart alone. Further, these knockouts can be inducible. In several mouse studies Tamoxifen is used to induce the Cre recombinase
Cre recombinase
Cre recombinase, often abbreviated to Cre, is a Type I topoisomerase from P1 bacteriophage that catalyzes site-specific recombination of DNA between loxP sites. The enzyme does not require any energy cofactors and Cre-mediated recombination quickly reaches equilibrium between substrate and reaction...
; in this case Cre is under control of the mouse estrogen receptor (Mer) in a MerCreMer system. Tamoxifen antagonizes the Mer to activate Cre recombinase allowing it to act on the floxed gene.