Fig. 7. Domain III of GBP is important for normal particle formation in Xenopus eggs. (A-F) Activated eggs expressing wild-type (WT) GBP-GFP (A,D), C-III-GFP (B), GFP alone (C), N-III-GFP (E) or -II-GFP (F) were fixed during peak cortical rotation and the shear zone was imaged from the vegetal pole with a scanning laser confocal microscope. Scale bars in A,D: 10 µm. A and B are from one experiment, and C-F are from a second experiment. (G-H) GBP-GFP constructs are expressed at similar levels. (G) Eggs were injected with WT GBP-GFP or C-III-GFP RNAs and prepared as for the live imaging experiments. Egg lysates were then Western blotted with an anti-GFP antibody. (H) Eggs were injected with WT GBP-GFP, -II-GFP, N-III-GFP or GFP RNAs, and processed as in G.