C3^tm1Pkna

3.5 kb of the gene, a region including exon 24, was replaced with a neomycin resistance cassette via homologous recombination. Western blot analysis showed an absence of C3 beta-chain protein in the serum of homozygous mutant animals. Similarly, ELISA assay did not detect C3 protein in serum from homozygous animals. (J:45857)