Acr^tm1Tba

A neomycin selection cassette was used to replace a portion of exon 2 and all of exon 3. The deleted region encoded His70 and Asp124, which are required for serine protease activity, as well as 5 Cys residues involved in disulfide bonds. Northern analysis using a cDNA fragment containing exons 2 and 3 showed an absence of mRNA in extracts isolated from the testes of homozygous mutant mice. Protease activity in cauda epididymal sperm was assayed and found to be absent in homozygous animals. (J:21944)