Cbfb^tm1Spe

A neomycin resistance gene replaced the 5' end of exon 5. This mutation is predicted to result in a protein that lacks four amino acids of the heterodimerization domain. RT-PCR analysis on RNA derived from embryos demonstrated that transcripts lacking exon 5 were produced from this allele. Western blot analysis on extracts from ES cells and homozygous embryos confirmed that an aberrant protein was made that appeared to lack sequences encoded by exon 5. (J:36593)