Igh^tm1Cys

An FRT-flanked neomycin resistance cassette was inserted in reverse orientation just downstream of the DQ52 region in a plasmid containing DQ52 (Igh-D). A heavy chain variable-diversity-joining (VDJ) segment of HyHEL10 sequences were placed downstream of the neomycin cassette, replacing the Igh-J (Jh1-4) locus. A loxP site was added to a downstream SpeI restriction site, between the Igh-6 (IgM/mu) enhancer and the Igh-6 switch region, for use in future gene targeting. The immunoglobulin heavy chain locus is of the Igha allotype. (J:118931)