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.

The current estimate is that roughly 1.7 × 10 25 new viruses are produced every second (142) . The vast majority infect microbes, and the estimated number of phages is 10 31 (143) . Of the 5000 plus phages examined under the EM in one study, 96% are 'tailed phages' and one of the three main phage groups are lambda-like (another is T7like) (144) . The number of just G-T type frameshifting per second has to be a vast number. Frameshifting and phage tail assembly. Phage lambda and many other dsDNA phages gene g encodes gpG, a tail assembly chaperone, that binds to multiple regions of the tape measure protein gpH. Near the 3 end of the g coding sequence, a small proportion of translating ribosomes shift -1 and continue to synthesize the fusion protein gpGT. The 'G' portion of gpGT binds to the tape measure protein gpH, while the 'T' region binds the major tail protein gpV, linking them and mediating the initiation of gpV on gpH. However, gpG and gpGT both dissociate from the assembly, aiding the fast polymerization of gpV on the initiator complex to form the mature tail. Finally, the head binds to the fully mature tail to form phage lambda. The tRNA Lys wobble anticodon nucleotide shown as U*, represents uridine with a 5-methylaminomethyl-2-thiouridine (mnm 5 s 2 U) modification.