Ribosomal frameshifting and transcriptional slippage: From genetic steganography and cryptography to adventitious use

Atkins, John F.; Loughran, Gary; Bhatt, Pramod R.; Firth, Andrew E.; Baranov, Pavel V.

Nevertheless, about 87% of bacterial RF2 coding sequences do have an in-frame UGA early in their coding sequence (348) . In the E. coli RF2 gene it is codon 26 (350) . After the short initial zero-frame ORF, the rest and great majority of the coding sequence is in the +1 frame with +1 ribosomal frameshifting being obligatory for RF2 synthesis. At high levels of release factor 2, there is efficient termination at the UGA and the resulting short peptide is rapidly degraded. With progressively lower levels of RF2, there is increasingly more efficient frameshifting at the codon 5 adjacent to the UGA and restorative synthesis of RF2 (54, (351) (352) (353) . The nt 3 adjacent to the UGA is nearly always C and, as this disfavors strong termination at the UGA (354), it is important for this frameshifting serving a sensitive autoregulatory function.