Figure 1. Scheme for incorporating unnatural amino acids into proteins in C. elegans.

The Uaa must be able to enter the worm and be transported into cells of the target tissue. An orthogonal tRNA/RS pair evolved to be specific for the Uaa should be expressed in the target cell together with the gene of interest. An amber stop codon UAG is introduced at the desired site for Uaa insertion in target gene. The orthogonal RS charges the Uaa onto the orthogonal tRNA, which recognizes the UAG codon and incorporates the Uaa during translation.