Ntrk2^tm1Lfr

The first exon (exon S) was replaced with a floxed full-length cDNA copy of the gene followed by a PGK-neo-loxP cassette and a tau-lacZ cassette. The PGK-neo-loxP cassette was removed in correctly targeted ES cells via transient expression of cre recombinase, leaving the floxed cDNA and tau-lacZ cassette intact. Expression of the floxed cDNA is under the control of the endogenous promoter. The tau-lacZ sequence is not transcribed due to SV40 polyadenylation signals and multiple stop codons following the floxed cDNA. Northern blot analysis of brain from homozygous mutant animals shows the presence of only full-length transcripts. Multiple alternative transcripts observed in wild-type animals are absent. Gene expression and protein expression in mutant animals is approximately 33% and 24% that of wild-type, respectively. Immunohistochemical analysis demonstrated that only full-length protein, and no protein isoforms, are expressed in mutant animals, and the pattern of expression is similar to wild-type. (J:69123)