Psen1^tm1Mpm

Point mutations were introduced into the coding region of exon 5 that altered the codons corresponding to amino acids 145 and 146 from isoleucine and methionine to valine and valine, respectively, and a BstEII restriction site. A lox-P flanked neomycin cassette was also introduced into exon 4. F2 mice exhibited the expected polymorphism of the targeted allele when genomic DNA was amplified with exon 5 specific primers and the products were digested with the appropriate restriction enzyme. Northern blot analysis of total brain RNA using a Psen1 specific antibody showed that the targeted allele was expressed at normal physiological levels in homozygous mutant mice. (J:51950)