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.

Several papers have addressed the potential for altered modification status of the frameshifting relevant tRNAs during the course of retroviral infection to occur and relate to gag frameshifting efficiency (628) (629) (630) . It is clear from two major studies and earlier work cited that in bacteria certain tRNA undermodification enhances frameshifting (391, 631) and metabolism and growth conditions influence modification levels (632) . Of relevance to ribosomal frameshifting at U-rich sequences are studies in thermophilic archaea (633, 634) and in Drosophila (635) which have shown organism-specific differences in the degree of conversion of 1-methyl G to wye in the tRNA Phe anticodon loop. Studies in S. cerevisiae with the frameshifting utilized by the double-stranded RNA virus L-A found increases with reduced wye modification of tRNA Phe leading the authors to wonder if the degree of modification in some organisms is related to finely tuned tRNA Phe -dependent frameshifting (636) .