PDGF A-CHAIN GENE IS EXPRESSED BY MAMMALIAN NEURONS DURING DEVELOPMENT AND IN MATURITY

Platelet-derived growth factor (PDGF) may be a critical factor in the temporal differentiation of glial elements in the mammalian central nervous system. We have used in situ hybridization and immunoperoxidase staining to investigate the localization of PDGF A and have observed high levels of PDGF A-chain mRNA and immunoreactive PDGF A in neurons of embryonic and adult mice. PDGF A-chain expression was shown to be developmentally regulated and tissue specific. Every neuronal population examined in the central and peripheral nervous systems expresses PDGF A transcripts. Variable, significantly weaker signals are observed in glial cells. In contrast to known neurotrophic factors, the PDGF A transcripts are widely distributed among neurons. This generalized distribution of PDGF A transcripts, together with the known effects of PDGF on glial cells in vitro, suggests a unique role of neurons in regulating the proliferation and differentiation of glial cells in vivo.