Oprk1^{tm1.1(cre)Sros}

The coding region of the gene in exon 2 was replaced with a Cre recombinase gene followed by a polyadenylation sequence. An Frt-flanked neomycin selection cassette was inserted at the 3' end, but removed by flp-mediated recmobination in the final allele. (J:229097)