Cux1^tm1Mbu

Exon 22 was fused in-frame to a lacZ cassette and exon 23 was replaced with a neomycin resistance cassette via homologous recombination. The mutation results in deletion of the C-terminal Cut repeat 3 and homeodomain, which disrupts all CDP isoforms. The CASP isoform remains unaffected although it is transcribed at 6-fold lower levels compared to wild-type. Expression of the CDP-lacZ fusion protein was verified by Western blot analysis of mouse embyronic fibroblasts (MEFs) derived from homozygous mutants. The fusion protein lacks gene repression activity and is therefore a null allele. (J:71407)