Coming soon to a worm near you....

Three possible stop codons are common in mRNA: UGA, UAA and UAG. These codons usually bind release factors, that prompt the release of of the nascent amino acid chain from the ribosome. Some organisms, however, contain tRNA complementary to one of these codons. In these organisms, that codon no longer triggers the ending of the translation process, but codes an amino acid instead. Several researchers have used this special tRNA to develop mutant cells with expanded genetic codes.Greiss and Chin have now taken this a step further: they have engineered a mutant strain of the worm C. elegans that translates every UAG codon as an artificial aminoacid. It was a complex endeavour (details are in their paper...) that surely would have deserved a well-publicized press conference :-)