Fig. 1. LIF and BMP both increase GFAP expression but promote different morphologies. (A) Western analysis demonstrates that endogenous BMP4 is present in E18.5 EGF-responsive neurosphere cultures. Preabsorption of the antibody with BMP4 (preabsorb) eliminates the band. (B,C) Quantitative PCR analysis illustrates that noggin inhibition of endogenous BMP decreases GFAP levels, whereas exogenous LIF and BMP4 increase GFAP levels in dissociated neurospheres plated for a 20-hour differentiation. Note that BMP treatment produces the highest level of GFAP. (D-F,H,I) Immunofluorescence reveals that 7-day LIF and BMP4 treatments promote different GFAP-expressing cell morphologies. Red, GFAP; blue insets, Hoechst nuclear counter stains. (D,H,J) BMP4 treatment produces a stellate morphology with an increased process number. (E,J) LIF treatment alone induces a mixture of elongated bipolar/tripolar and stellate morphologies. (F,I,J) In the presence of noggin, LIF promotes the bipolar/tripolar morphology and reduces process number. (G) Quantitation of GFAP immunofluorescent cells. Noggin treatment significantly reduces the number of GFAP⁺ cells. Conversely, LIF, and LIF plus noggin, treatment increases the number of GFAP⁺ cells and BMP4 treatment results in an even larger increase. (G) ^*P<0.05, ^**P<0.001; (J) ^*P<0.01, ^**P<0.001 ANOVA. Error bars are ±s.e.m. Scale bars: 20 µm in D-F;10 µm in H,I.