Fig. 7.

Differentiation of astrocytes is transcription-dependent. A, NE cell cultures were stimulated with CNTF (30 ng/ml) for 30 min in the absence or presence of DRB, a reversible inhibitor of RNA synthesis, as described previously (Williams et al., 1997). After 4 d incubation in factor-free medium, cells were assessed for GFAP expression using mAb. The percentage of GFAP-positive cells per culture is shown. * denotes 0. B, As controls for the experiment inA, NE cell cultures were stimulated with CNTF (30 ng/ml) for 15 min in the absence or presence of DRB. Cell lysates were then processed and immunoblotted with anti-gp130, anti-STAT 1, and anti-STAT 3 mAbs.