The targeted KO-first, conditional ready, lacZ-tagged mutant vector PRPGS00088_C_F09 vector from the EUCOMM targeting project 69413 was used to insert an FRT site followed by, splice acceptor site, lacZ sequence with polyadenilation sequence, and a loxP site, followed by neomycin resistance gene under the control of the human beta-actin promoter, SV40 polyA, a second FRT site and a second loxP site into an intron 2 of the gene. A third loxP site is inserted into intron 7. The critical exons 3 to 7 are thus flanked by loxP sites. (J:236096)