Vertebrate neuron-specific nuclear protein called NeuN (Neuronal Nuclei). Only one NeuN clone exists (A60) and reacts with an uncharacterized nuclear protein. MAB-94161 reacts with most neuronal cell types throughout the nervous system of mice including cerebellum, cerebral cortex, hippocampus, thalamus, spinal cord and neurons in the peripheral nervous system including dorsal root ganglia, sympathetic chain ganglia and enteric ganglia. The immunohistochemical staining is primarily in the nucleus of the neurons with lighter staining in the cytoplasm. The few cell types not reactive with MAB-94161 include Purkinje, mitral and photoreceptor cells. Developmentally, immunoreactivity is first observed shortly after neurons have become postmitotic, no staining has been observed in proliferative zones. The antibody is an excellent marker for neurons in primary cultures and in retinoic acid¬stimulated P19 cells. It is also useful for identifying neurons in transplants.