Translational recoding in archaea

Translational recoding includes a group of events occurring during gene translation, namely stop codon readthrough, programmed +/- 1 frameshifting, and ribosome bypassing, which have been found in organisms from all domains of life. They serve to regulate protein expression at translational level and represent a relatively less known exception to the traditional central 'dogma' of biology that information flows as DNA -> RNA -> protein and that it is stored in a co-linear way between the 5'-> 3' of nucleic acids and N -> C-terminal of polypeptides. In archaea, in which translational recoding regulates the decoding of the 21st and the 22nd amino acids selenocysteine and pyrrolysine, respectively, only one case of programmed -1 frameshifting has been reported so far and further examples, although promising, have not been confirmed yet. We here summarize the current state-of-the-art of this field that, especially in archaea, has relevant implications for the physiology of life in extreme environments and for the origin of life.