Figure 4.

Cellular distribution of αβ-tubulin antibody binding in the cranial neural ectoderm of neurulating rat embryos after 18 and 24 hr of culture. Indirect immunofluorescence of sections with αβ-tubulin antibody of embryos cultured on bovine sera that were either methionine-supplemented (A and B) or unsupplemented (C and D) at 18 hr (A and C) or 24 hr (B and D) of culture. AP, apical (lumen side) side of neural ectoderm cells and basal (BA) (side distal to the lumen) side of neural ectoderm cells; ATP, apposing tips of the neural folds. (×500.)