Ngfr^tm1Jae

A neomycin selection cassette was inserted into the third exon of the gene, disrupting the sequences encoding cysteine repeats 2, 3, and 4. Northern blot analysis revealed that the mutant gene did not yield a full length mRNA, however subsequent RT-PCR analysis, described in J:71955, detected an endogenous alternative transcript which lacks exon 3. Western blot analysis showed that the full length isoform was absent in homozygous mutant mice, but an isoform lacking cysteine repeats 2, 3, and 4 was present in both wild and mutant mice. In vitro experiments showed the persisting isoform to be a transmembrane protein that cannot bind neurotrophins but interacts with tyrosine kinase receptors. (J:43748, J:71955)