Figure 1.

Strategy for green fluorescent protein (GFP)-labeled reversible conditional gene knockout (cKO). This method requires a conventional floxed allele (Flox) paired with a multi-functional reversible KO (ΔR) allele (top left), and sequential action of Cre and Flp recombinases (middle and bottom). Depicted are the status of the alleles (left) and the corresponding protein expression patterns (right). SA, splicing acceptor; Neo, neomycin resistance gene; FRT, Flippase recognition target (red dots).