AAV with TBG promoter driven FLPo

This AAV expresses FLPo driven by a liver TBG promoter.

TBG is a 0.8kb hybrid promoter based on the human thyroid hormone-binding globulin (TBG) promoter and microglobin/bikunin enhancer. This hybrid promoter has been used for liver-specific transgene expression.

FLPo is a codon-optimized version of FLPe that greatly increases the protein expression and the FRT recombination efficiency in mouse cells. FLP is a site-specific recombinase (SSR) from the _ integrase family which recognizes distinct 34 bp FRT sites. Like Cre/LoxP system, the FLP/FRT system has been widely used for gene expression and generating conditional knockout mice, mediated by the FLP/FRT system. Initial use of FLP in mammalian cells revealed inefficient recombinase activity due to thermal instability of the FLP protein. Subsequent screening for thermostable mutants resulted in the identification of FLPe which has a 4-fold higher recombination efficiency at 37oC than original FLP. However, the recombination efficiency of FLPe in cells remains very low relative to other recombinases because of its non-mammalian origin. FLPo is engineered by codon optimization of FLPe, and gives much higher expression and activity than FLPe.