The targeting vector is designed to insert a human ubiquitin C promoter, a loxP-flanked STOP cassette, a human ARMS2 cDNA tagged with a Flag epitope, and an FRT-flanked neomycin cassette upstream of the Htra1 promoter. Mice do not have the ARMS2 gene. Flp-mediated recombination removed the neo cassette. Cre-mediated recombination removed the STOP cassette. The expression of endogenous Htra1 in the cortex is decreased by 22% in early adult mice. (J:343288)