Amber Suppressor (Molecular Biology)

Amber suppressors are mutant tRNAs that translate the UAG (amber) termination codon as a sense codon. Amber mutations cause protein synthesis to terminate prematurely, resulting in inactive, truncated polypeptides. Amber suppressors allow for protein synthesis beyond the translational block resulting in active protein. Hence the term "suppressor;" these mutant tRNAs "suppress" the phenotypes of amber mutations. These suppressors have been extensively used in prokaryotic genetic studies, and in studies of the translational apparatus and mechanisms. For complete discussions of these and other suppressors, see Nonsense Suppression, Suppressor tRNA, and Genetic Suppression.