Expression of the alpha subunit of 7S nerve growth factor in the mouse submandibular gland.

alpha-NGF is an inactive serine protease that is associated in the mouse submandibular gland with a closely related serine protease, gamma-NGF, and the neurotrophic factor, beta-NGF. The heterogeneity of purified alpha-NGF has been examined by DEAE-cellulose chromatography and SDS polyacrylamide gel electrophoresis. A possible explanation for the observed heterogeneity is presented. Antibodies have been prepared against alpha-NGF and purified by affinity chromatography so that they do not cross-react with gamma-NGF. This antibody preparation recognizes two very similar proteins in male mouse submandibular gland RNA-directed cell-free translation mixtures. The expression of only one of these forms is regulated by testosterone. Oligonucleotide probes specific for each of the three NGF subunits have been prepared and used for Northern blot analysis of RNA from the mouse submandibular gland. The three subunits were found to be coordinately expressed and each were 30-fold more abundant in male than in female glands.