Fig. 5.

Shh protein is present in embryonic CSF. (A) Embryonic CSF harbors Shh protein, as assayed by ELISA. The two white lines in A depict capillary tube inserted into the fourth ventricle to retrieve fresh CSF. ShhNp (starting at 0.063 nM) was used as positive control, whereas NIH 3T3 cell-conditioned media served as negative control in the analyses. (B) Primary cilia are present in proliferative radial glial VZ cells. The white frames in acetylated tubulin/Sox2 staining represent zoomed-in areas shown in the adjacent panels. Note that the white arrows indicate acetylated tubulin–labeled cilia protruding into the fourth ventricle.