Gonad Microinjection: A Method of Compound Delivery Directly into the Germline of C. elegans

- To prepare for the injection, use a worm pick to lay a track of halocarbon oil on an agarose pad. Place worms in the oil and immobilize them by gently pushing them onto the agar pad. Ensure the oil fully covers the animals. It allows oxygen to get to the worms while preventing desiccation. Next, place the agarose pad on an injection microscope and position the needle perpendicular to the worm, targeting the distal end of a gonad arm.

Gently push the needle through the cuticle and inject the gonad arm with the nucleic acid or compound of interest. Each gonad arm contains a germline syncytium that will develop into individual oocytes. Material injected into the distal gonad will be incorporated into those oocytes and affect the next generation.

After injecting worms, replace the oil with M9 buffer. Once the worms start moving, transfer them to an NGM agar plate with bacterial food. In the following protocol, the gonad microinjection method is used to deliver a Cas9 complex to target and edit the dpy-10 gene.

- Begin with preparation of C. elegans and agarose pads as described in the text protocol. Place an agarose injection pad and cover slip onto a dissection scope. Use a worm pic