Mice heterozygous for Efnb2tm2Kln were bred with mice expressing a cre recombinase transgene, resulting in the excision of a floxed neomycin resistance gene. The inserted sequence, which inclduded a cDNA encoding the full length protein and a hemagglutinin (HA) epitope tag, was left intact. The expression pattern of the targeted allele was determined to resemble that of the wild-type allele via in situ hybridization. Analysis using modified receptors showed localization to the cell surface. (J:67296)