Yolk removal. Embryos with yolk (Y) were analysed in comparison with embryos after one-step deyolking (D) or after two additional wash steps (W). A. Total protein amount per embryo as determined by DC protein assay (Bio-Rad). B. Coomassie stain (0.5 embryos loaded per lane). C. Western blot against Tubulin and MEK (0.5 embryos loaded per lane). While yolk proteins were efficiently depleted, recove