US Patent 6964859 Suppressor tRNA system

The present invention provides techniques and reagents for read-through of stop codons in mammalian cells. In certain embodiments, the invention provides methods in which a mammalian cell is contacted with a synthesized tRNA so that the tRNA is taken up into the cell at levels that allow read-through of stop codons. Preferably, the synthesized suppressor tRNA is aminoacylated, optionally with an unnatural amino acid. In certain preferred embodiments, the inventive system is utilized to generate proteins containing two or more unnatural amino acids.