The targeted KO-first, conditional ready, lacZ-tagged mutant vector PRPGS00072_A_A02 from the KOMP project 39930 was obtained from UC Davis KOMP-CSD and was used to insert an FRT site followed by, splice acceptor site, IRES, lacZ sequence with polyadenylation 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 intron 2 of the gene. A third loxP site is inserted into intron 3. The critical exon is thus flanked by loxP sites. (J:324270)