1. When they reach stage 8, remove the vitelline membranes from a group of embryos using sharpened forceps. Half the embryos should have been lineage-labeled by injection of fluorescein-lysine-dextran injection, and half should be uninjected. Transfer embryos to 75% NAM.
2. Dissect animal pole regions from the center of the pigmented regions of the labeled embryos. This can either be done using a pair of forceps as "scissors" or by using a "picking" motion with a tungsten needle. During dissection, the embryo can be kept still using a pair of forceps held in the other hand.
3. Dissect vegetal pole regions from uninjected embryos as described above for animal pole regions.
4. Place an animal pole region with its originally outer surface down, and position a vegetal pole region on top of it such that its originally outer surface is up. The two pieces of tissue will adhere to each other quickly, but care should be taken not to disturb the conjugate for at least 10 min.
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