Visualization of Axonal Projection Patterns of Embryonic Motor Neurons in Drosophila

Begin with a tube containing late-stage-16 Drosophila embryos in a mounting medium.

The motor neurons of Drosophila are immunolabeled.

Transfer an embryo to a glass slide and remove it from the mounting medium.

Then, place the embryo ventral side up and dissect it.

Orient the anterior section containing the motor neurons with the dorsal side up.

Using a tungsten needle, cut along the dorsal midline and spread the body wall. Move the embryo into the mounting medium. Then, remove the internal organs to expose the labeled

neurons.

Transfer the embryo to a new slide, then mount and seal it.

Observe under a differential interference contrast microscope as light passes through the embryo, generating a high-resolution image.

The labeled neurons with axonal projection patterns appear dark brown on a light background.

Motor neurons branch into two major nerves: the intersegmental and segmental nerves, and a minor branch, the transverse nerve, that innervates the muscles.

To fillet the embryos, stage them on a glass slide

First, move them into a drop of glycerol ventral side up. Next, under a dissection microscope, cut off the anterior part at 1 quarter of the body length. And remove the most posterior