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.

A stem loop structure 5 of the barley yellow dwarf virus shift site was found to have a 50% effect on in vivo frameshifting and is conserved in all members of the Luteovirus and Dianthovirus genera (110) . These upstream stem loop(s) were suggested to either slow the ribosome in advance of the shifty site to enhance frameshifting, or serve as 'insulators' to prevent improper folding of the shifty site or 3 long range structural element with upstream sequences (110) . This finding emerged close to the time of an early report of sequence immediately 5 of the HIV-1 and HTLV-2 shifty sites influencing frameshifting efficiency (503) . The stem loop structure noted above that is 5 of the gene 60 take-off site region and important for bypassing, has been proposed to propel ribosomes through the 5 segment of the coding gap. It is explicable by an mRNA zippering effect as mRNA emerges from the mRNA exit channel (451, 485) .