PROLIFERATION AND DIFFERENTIATION PROPERTIES OF BIPOTENT GLIAL PROGENITOR-CELL LINES IMMORTALIZED WITH THE ADENOVIRUS E1A GENE

Bipotent glial progenitors have been immortalized by the transfer of t he adenovirus EIA gene into primary cultured cells from embryonic rat brain. The lines obtained are phenotypically untransformed, retain gro wth contact-inhibition, and are able to differentiate, unless they are surtransfected with transforming oncogenes. Depending on the growth c onditions, these immortalized cells express differentially either olig odendrocyte or astrocyte-specific markers and genes. After being seede d in serum-free medium, they display gangliosides recognized by A2B5 m onoclonal antibody, and then they express sequentially 04 epitopes, ga lactocerebroside, and the myelin protein DM20. When grown in serum-sup plemented medium, the cells express at first A2B5 epitopes, and then t ransiently 04 and galactocerebroside; after reaching confluence, 04 an d galactocerebroside become undetectable, whereas the cells begin to c oexpress glial fibrillary acidic protein and glutamine synthetase. The se results indicate that the cell lines can undergo a differentiation reminiscent both of O-2A progenitors and of plastic process-bearing gl ial sub-populations. The cells were also genetically marked by the sta ble introduction of the nlslacZ reporter gene. Thus, the lines could b e useful for studying direct interactions in vitro, or for post-grafti ng investigations. They should also provide a model for studying the m echanisms involved in the commitment and in the control of proliferati on and differentiation of this cell lineage. This suggestion is consis tent with the data indicating a growth arrest-dependent differential e xpression of a novel gene encoding a protein with a helix-loop-helix d omain. (C) 1993 Wiley-Liss, Inc.