The targeting arms and same general strategy used to produce the Opn4tm1(cre)Saha allele (MGI:4881482) was employed to generate this allele. Differences are that the targeting construct contained the rabbit beta-globin intron, the cre/ERT2 sequence, and an IRES-lacZ cassette downstream of the melanopsin (Opn4) start codon. (J:167871, J:174940)