Expression of a TGF beta regulated, brain-specific mRNA in serum-free mouse embryo (SFME) cells.

The serum-free mouse embryo (SFME) cell line was isolated from 16-day-old Balb/c mouse embryos in medium in which the usual serum supplement to the culture medium was replaced by purified growth factors and other components. SFME is an unusual line that does not undergo senescence in vitro, maintains an apparently normal karyotype, and is growth inhibited by serum. Transforming growth factor beta (TGF beta) or calf serum induces expression of the astrocyte marker glial fibrillary acidic protein (GFAP) in these cells, and similar cells can be isolated directly from brain. By differential screening of a cDNA library derived from SFME cells, a calf serum- and TGF beta-regulated 8.5 kb mRNA was identified in SFME cells and the cDNA partially sequenced. This mRNA was detected only in RNA preparations from brain among a number of tissues examined, and may provide an additional marker of TGF beta-regulated differentiation in these cells.