Ctsd^tm1Cptr

Exon 4 was disrupted by the insertion of a neomycin selection cassette, which altered the reading frame. One of the two active site aspartic acid residues and half of the proteinase region were downstream of the frameshift mutation. A lack of transcript in homozygous mutant mice was determined by Northern blot analysis of total kidney RNA. Western blot analysis of fibroblasts obtained from homozygous mutant embryos showed an absence of encoded protein. Proteinase activity was shown to be ablated in homozygous mutant mice by assaying hemoglobin degradation. (J:28201)