In the conditional knockout mouse model, the gene of interest is deleted only in selected cells, as determined by a tissue-specific promoter. Conditional knockout mice are usually generated using Cre-LoxP, Dre-Rox, or Flp-Frt recombination systems for permanent gene alterations in specific tissues. The targeted fragment to be knocked out is flanked by LoxP elements. Floxed mice are then bred with tissue-specific Cre or CreERT2 mice, and sequences between LoxP sites will be removed from the offspring’s genome in a spatial and/or temporal manner.
