Fig. 9: Schematic representation of the generation of premature termination codon (PTC) influenza viruses using the genetic code expansion strategy.
From: Synthetic biology-inspired development of live attenuated influenza vaccines
PTC-viruses are generated in transgenic cell lines that express an orthogonal tRNA (tRNACUA), tRNA synthase (pylRS), and a gene encoding an amber codon–containing GFP (GFP39TAG). In the presence of an unnatural amino acid (UAA), the PTC-viruses replicate effectively in transgenic cells. In conventional cells without the orthogonal translation machinery, the insertion of PTCs halts the translation of relative viral proteins, which subsequently attenuates the PTC-viruses.
