Neural progenitor cells have been isolated from the embryonic central nervous system (CNS) of several mammalian species. These exhibit properties of immature cells, including expression of the intermediate filament protein Nestin, the ability to self renew, and to give rise to terminally differentiated cell types. In this study we describe some of the properties of ST14A cells, which were established via retroviral transduction of the temperature-sensitive mutant of the SV40 Large T Antigen into primary cells derived from the embryonic day 14 (E14) rat Striatum primordia. At 33 degrees C, ST14A cells proliferate and express Nestin, whereas at the nonpermissive temperature, cell growth becomes restricted in coincidence with the disappearance of the immortalizing oncoprotein, We also describe the ability of ST14A cells to differentiate and express MAP2. Furthermore, we analyzed the expression of specific growth factors and growth factor receptors in the ST14A cells, and found that nerve growth factor (NGF) and Trk receptors are most commonly expressed.