Crmp1^tm1.1Swl

A multi-step targeting process consisting of the insertion and subsequent removal of a floxed HPRT cassette into intron 5, and the insertion of a second floxed HPRT cassette into intron 3 resulted in the flanking of exons 4-5 with loxP sites. Transient cre expression ultimately excised both exons and the second HPRT cassette. Northern blot and Western blot confirmed absence of transcript and protein, respectively, in mutants. (J:120105)