The gene was disrupted by replacement of exons 1 and 2 with a PGK-neo cassette via homologous recombination resulting in deletion of the first 131 amino acids and a downstream frameshift. Homozygous mutant embryos were detected by PCR genotype analysis up to day E14.5. Western blot analysis of mouse embryonic fibroblasts derived from E12.5 homozygous mutant embryos showed an absence of protein product, thus confirming inactivation of the gene.