The comparision of expression pattern of IGFBP-4 protein in the forebrain at E14.5 and E16.5. (A, B) At day E14.5, the positive signal for IGFBP-4 protein was detectable widespread in brain regions including VZ. (C, D) At day E16.5, the positive signal for IGFBP-4 protein was still detectable widespread in brain regions, but fluorescent signals were not found at any significant level in cells near the ventricle. (E, F) Negative control. LV-lateral ventricles. Scale bar = 30 μm in A,C,E; 10 μm in B,D,F.