Recent studies show that the nervous system contains many molecularly distinct cell types. Clonal cell marking experiments demonstrate that different cell types in some areas of the CNS are products of a multipotential stem cell. The factors controlling the differentiation of vertebrate CNS precursor cells would be more accessible to molecular analysis if cell lines with precursor properties could be established. Here we show that cell lines expressing an antigenic marker specific for a major brain precursor cell population can be established from rat cerebellum. We demonstrate that cell lines express the precursor, neuronal or glial properties depending on the growth conditions. This work supports the view that brain precursor cells expressing the marker Rat 401 are multipotential and can differentiate into cells with either neuronal or glial properties. Cell lines capable of differentiation should be useful in defining the signaling systems generating the cell types of the brain.