Evaluation of pro‐pol Frameshifting Efficiencies for Naturally Occurring Variants of HTLV‐1

Publication Summary

Human T‐cell leukemia Virus Type 1 (HTLV‐1) utilizes two ‐1 programmed ribosomal frameshifts (PRFs) to translate its enzymatic proteins. This translational mechanism induces a change in the ribosomal reading frame during elongation, which allows for the production of proteins from alternate reading frames within a single transcript. Frameshifting is utilized by many retroviruses and is often required for successful replication. Each frameshift site includes three components: a heptad “slippery sequence”, a spacer, and a downstream structure. Preliminary data from our group suggests that the HTLV‐1 pro‐pol frameshift site structure is a pseudoknot. Interestingly, multiple HTLV‐1 isolates include point‐mutations within this pseudoknot structure. How these mutations affect the ‐1 PRF efficiency is uncertain. Here, we investigate the impact of several pseudoknot point‐mutations on the HTLV‐1 pro‐pol frameshift efficiency. Site‐directed mutagenesis was used to insert these mutations into a dual‐luciferase vector that includes the HTLV‐1 pro‐pol frameshift site. The mutated DNA for each variant was transcribed, translated, and used in a dual‐luciferase assay, allowing calculation of the in‐vitro ‐1 PRF efficiencies for each mutant. Our preliminary data suggests that these point‐mutations create significant differences in the ‐1 PRF efficiency.