• NTRK1 is a membrane-bound receptor that upon neurotrophin binding, phosphorylates itself and members of the MAPK pathway. The presence of this kinase leads to cell differentiation and may play a role in specifying sensory neuron subtypes.
• NTRK gene fusions are the best-characterized aberrations among all NTRK alterations occurring in cancers. These gene fusions are known to be oncogenic, as they promote tumorigenesis through the constitutive activation of downstream cell growth and proliferative pathways.
• Receptor tyrosine kinase involved in the development and the maturation of the central and peripheral nervous systems through regulation of proliferation, differentiation and survival of sympathetic and nervous neurons. High affinity receptor for NGF which is its primary ligand.
• NGF has nerve growth stimulating activity and the complex is involved in the regulation of growth and the differentiation of sympathetic and certain sensory neurons.

NGF expression analysis in homozygous B-hNTRK1/hNGF mice by ELISA. Plasma were isolated from wild-type C57BL/6 mice (+/+) and homozygous B-hNTRK1/hNGF mice (H/H;H/H)(n=3, famale, 6-week-old), and analyzed by ELISA with NGF ELISA kit. NGF was detected in plasma of wild-type mice and homozygous B-hNTRK1/hNGF mice, as the ELISA kit is cross-recognize both human and mouse NGF.

Strain specific analysis of NTRK1 and NGF mRNA expression in wild-type C57BL/6 mice and B-hNTRK1/hNGF mice by RT-PCR. Brain RNA were isolated from wild-type C57BL/6 mice (+/+) and homozygous B-hNTRK1/hNGF mice (H/H; H/H), then cDNA libraries were synthesized by reverse transcription, followed by PCR with mouse or human NTRK1 and NGF primers. Mouse Ntrk1 and Ngf mRNA were detectable only in wild-type C57BL/6 mice. Human NTRK1 and NGF mRNA were detectable only in homozygous B-hNTRK1/hNGF mice but not in wild-type mice. And the PCR products were confirmed with Sanger sequencing.