NEURTURIN, A RELATIVE OF GLIAL-CELL-LINE-DERIVED NEUROTROPHIC FACTOR

THE normal development of the vertebrate nervous system entails the de ath of 30-70% of the neurons originally generated in most neuronal pop ulations(1), This naturally occurring cell death is regulated by speci fic neurotrophic factors that promote neuronal survival and which are produced in limiting quantities by target cells, glial cells and neuro ns. These factors are also of potential utility as therapeutic agents for neurodegenerative diseases(2). Here we describe the purification a nd cloning of a new neurotrophic factor, identified on the basis of it s ability to support the survival of sympathetic neurons in culture, T his factor, neurturin, is structurally related to glial-cell-line-deri ved neurotrophic factor (GDNF)(3). These factors can each activate the MAP kinase signalling pathway in cultured sympathetic neurons and sup port the survival of sympathetic neurons, as well as of sensory neuron s of the nodose and dorsal root ganglia, Thus, neurturin and GDNF toge ther now define a new family of neurotrophic factors.