Expression of IGFBP-4 protein at E13.5 by immunofluorescent staining. (A, B) Strong positive signal for IGFBP-4 protein was detected in the forebrain. (C, D) In the midbrain, positive signal of IGFBP-4 protein was detected, but it was slightly weaker than in the forebrain. (E, F) In the hindbrain, the positive signal for IGFBP-4 protein was similar to that in the midbrain. (G, H) Negative control. LV-lateral ventricles, AQ-cerebral aqueduct, V4-fourth ventricle. Scale bar = 30 μm in A,C,E,G; 10 μm in B,D,F,H.