A DEAD-box protein acts through RNA to promote HIV-1 Rev-RRE assembly

作者：Lamichhane Rajan; Hammond John A; Pauszek Raymond F III; Anderson Rae M; Pedron Ingemar; van der Schans Edwin; Williamson James R; Millar David P^*

来源：Nucleic Acids Research, 2017, 45(8): 4632-4641.

DOI：10.1093/nar/gkx206

The HIV-1 Rev protein activates nuclear export of un-spliced and partially spliced viral RNA transcripts, which encode the viral genome and the genes encoding viral structural proteins, by binding to and oligomerizing on the Rev Response Element (RRE). The human DEAD-box protein 1 (DDX1) enhances the RNA export activity of Rev through an unknown mechanism. Using a single-molecule assembly assay and various DDX1 mutants, we show that DDX1 acts through the RRE RNA to specifically accelerate the nucleation step of the Rev-RRE assembly process. Single-molecule Forster resonance energy transfer (smFRET) experiments using donor-labeled Rev and acceptor-labeled DDX1 show that both proteins can associate with a single RRE molecule. However, simultaneous interaction is only observed in a subset of binding events and does not explain the extent to which DDX1 promotes the nucleation step of Rev-RRE assembly. Together, these results are consistent with a model wherein DDX1 acts as an RNA chaperone, remodeling the RRE into a conformation that is pre-organized to bind the first Rev monomer, thereby promoting the overall Rev-RRE assembly process.

• 出版日期2017-5-5