Synb^tm2.1Ics

The wild-type gene was replaced by the same gene carrying a K14R point mutation in the ISU domain. The targeting vector contained a 4.3-kb 5-prime arm and a 5-kb 3-prime arm corresponding to sequences bracketing the syncytin-B ORF, a 2.6 kb fragment containing the syncytin-B unique ORF into which the K14R mutation was introduced and the neomycin resistance (neo) genes. The ORF and neo gene were flanked by FRT and LoxP recombination sites, allowing their conditional excision. In the recombinant mouse strain obtained, the FRT-flanked neo selection marker was removed by breeding with flp recombinase-expressing mice; the syncytin-B K14R mutant gene is flanked by LoxP recombination sites, allowing its conditional excision. (J:82809)