A 486 bp fragment was replaced with a neomycin selection cassette inserted by homologous recombination. The deleted region corresponded to nucleotides 954 through 1440 of the cDNA and encoded the first zinc finger pairs. The insertion of the cassette was reported to disrupt the open reading frame at codon 99. Protein was undetected by Western blot analysis of homozygous mutant mice. (J:79652)