Figure 5.

Localization of Asp in embryos treated with colchicine or taxol. Embryos were incubated in 5 mM colchicine or 25 μM taxol for 20 min before fixation (described in Materials and Methods). Embryos from the same batch were stained with antibodies to either γ- and α-tubulin (A and C) or Asp and α-tubulin (B and D) and with propidium iodide to show the mitotic chromatin (A–D). In the merged images, chromatin is colored in blue, tubulin in green, and Asp or γ-tubulin in red/orange. (A and B) 5 mM colchicine. (A) α-Tubulin staining is diffuse, suggesting all microtubules have been depolymerised. γ-Tubulin, as an integral centrosomal protein, is tightly focused at the centrosome. (B) α-Tubulin is not detectable, and Asp does not show any centrosomal localization. (C and D) 25 μM taxol. (C) Microtubules are stabilized and form astral arrays surrounding each centrosome. γ-Tubulin is found only at the centrosomes. (D) Asp staining is found throughout the area corresponding to the minus ends of the microtubules, and it is not focused at the centrosome. Bar, 10 μm.