Rr158^tm1Cgn

A neomycin resistance gene cassette controlled by the rabbit beta-globin promoter plus an enhancer element containing four tandem repeats of the GTIIC+GTI motif, which is active only in ES cells, was used in this allele. This cassette replaced the immunoglobulin kappa chain intron enhancer (Ekappa) sequence, located between Igkj and Igkc gene segment clusters, containing the octamer site, the NF-kappaB binding site, kappa E1-E3, and the kappa silencer. (J:12574)