The Highly Conserved Codon following the Slippery Sequence Supports -1 Frameshift Efficiency at the HIV-1 Frameshift Site

Mathew, Suneeth F.; Crowe-McAuliffe, Caillan; Graves, Ryan; Cardno, Tony S.; McKinney, Cushla; Poole, Elizabeth S.; Tate, Warren P.

Alternatively, the measured difference in frameshift efficiency observed in our system could be influenced by a difference in activity of the short form of the Renilla luciferase enzyme, terminated at either the intercodon (if changed to a stop codon) or the downstream 0-frame stop codon. When utilising a suppressor tRNA to compete with endogenous eRF1, a minor fraction of the non-frameshifted product would be expected to bypass the 0-frame stop codon and terminate at a downstream stop signal by readthrough; a difference in activity or stability between these two forms of the short enzyme could in principal account for the apparent competition effect observed in Fig. 6C and this possibility cannot be discounted. As only a fraction of the short enzyme species would have this short extension, however, a substantial change in specific activity would be required to yield the statistically significant difference seen in Fig. 6C .