This allele was generated by breeding mice heterozygous for Cnr1tm1Ltz with transgenic mice ubiquitously expressing cre recombinase. Southern blot analysis showed that the entire open reading frame was removed, leaving a single loxP site and the FLP-recombinase target (FRT) flanked neo transgene in the single exon at this locus. A lack of transcript was determined via in situ hybridization of homozygous mutant embyros. (J:77936)