Genetic Code Supports Targeted Insertion of Two Amino Acids by One Codon

Authors

Anton Turanov, University of Nebraska-Lincoln
Alexei Lobanov, University of Nebraska-Lincoln
Dmitri E. Fomenko, University of Nebraska-LincolnFollow
Hilary Morrison, Josephine Bay Paul Center, Marine Biological Laboratory
Mitchell Sogin, Josephine Bay Paul Center, Marine Biological Laboratory
Lawrence Klobutcher, University of Connecticut Health Center
Dolph Hatfield, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MDFollow
Vadim N. Gladyshev, University of Nebraska-LincolnFollow

Date of this Version

1-9-2009

Comments

Published in SCIENCE vol. 323.

Abstract

Strict one-to-one correspondence between codons and amino acids is thought to be an essential feature of the genetic code. However, we report that one codon can code for two different amino acids with the choice of the inserted amino acid determined by a specific 3’ untranslated region structure and location of the dual-function codon within the messenger RNA (mRNA). We found that the codon UGA specifies insertion of selenocysteine and cysteine in the ciliate Euplotes crassus, that the dual use of this codon can occur even within the same gene, and that the structural arrangements of Euplotes mRNA preserve location-dependent dual function of UGA when expressed in mammalian cells. Thus, the genetic code supports the use of one codon to code for multiple amino acids.