Molecular cloning of the chicken nerve growth factor gene: mRNA distribution in developing and adult tissues

The gene for chicken nerve growth factor was cloned by screening a chicken genomic library with a mouse nerve growth factor cDNA clone. Northern blot analysis indicated the presence of nerve growth factor mRNA throughout the central nervous system of the chick, with the highest levels in retina, midbrain/hindbrain and spinal cord. In embryonic brain, nerve growth factor mRNA was expressed at low levels at day 8, with a progressive increase up to postnatal day 2. Substantial amounts of nerve growth factor mRNA were expressed in embryonic leg tissues at a time when the dorsal root ganglia that project to the limb are maximally responsive to nerve growth factor.