Exon 10 was modified to contain the Ntrk3 coding sequence for the transmembrane and intracellular regions (amino acids 431-824), IRES, Cherry reporter, polyadenylation sequence and floxed neomycin resistance cassette. Cre-mediated recombination removed the selection cassette. The protein product is a fusion of the extracellular region of Ntrk1 with the transmembrane and intracellular regions of Ntrk3. (J:210892)