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.

Because of the enormous number of IS elements, and the prevalence of their utilization of frameshifting for transposase expression, they constitute one of the richest sources of frameshift cassettes. Most of the work on IS element frameshifting, including all the early studies focused on IS elements where the frameshifting is at the translational level. In particular, detailed studies by Olivier Fayet and colleagues (192) (193) (194) (195) , has provided insights into a variety of −1 ribosomal frameshifting features not revealed by high level frameshifting, including frameshifting without P-site re-pairing following dissociation, dual use of stimulatory elements and detailed knowledge of shift site usage. IS elements that use +1 ribosomal frameshifting have not been identified. However, several of the more recent studies have focused on IS elements where transcriptional realignment yields the transposase product that is encoded trans-frame with respect to the DNA sequence. In several of these the shift is +1 (99, (196) (197) (198) .