Preparing late whole-mount Drosophila embryos for immunostaining

INTRODUCTIONThe choice of fixation and permeabilization methods for examining flies depends on the stage of development. Early and late embryos are treated with a mixture of organic solvents, formaldehyde, and alcohols. The cuticles of late-stage embryos (17-22 hours or until hatching) are usually opened by sonication, as described here. Tissues from later stages of development are normally dissected by hand and then fixed and stained in a standard paraformaldehyde/detergent combination.