Recognition of nonsense codons in mammalian cells

The tritiated trinucleotide UGA was used in a binding assay to detect transfer RNAs that recognize this nonsense codon from calf-liver cells. Acylation of transfer RNA with labeled amino acids and determination of codon responses of aminoacyl-tRNAs demonstrate that a species of seryl-tRNA and a species of arginyl-tRNA recognize the codon UGA. Slight responses of cysteinyl-tRNA and of trytophanyl-tRNA to the codon UGA were also observed.