Psen1^tm1Shn

Exon 3 of the Psen1 gene, encoding the translation initiation codon, was deleted and replaced with a neomycin cassette. Northern blots of brain tissue from homozygous mutant mice showed a small amount of mutant Psen1 mRNA, smaller in size than wild-type Psen1. IP-Western blotting detected no C-terminal protein fragment in homozygous mutant mice. The authors conclude that this mutant is a null allele. (J:40365)