DDX17 promotes the production of infectious HIV-1 particles through modulating viral RNA packaging and translation frameshift

Abstract

RNA helicases are a large family of proteins that rearrange RNA structures and remodel ribonucleic protein complexes using energy derived from hydrolysis of nucleotide triphosphates. They have been shown to participate in every step of RNA metabolism. In the past decade, an increasing number of helicases were shown to promote or inhibit the replication of different viruses, including human immunodeficiency virus type 1. Among these helicases, the DEAD-box RNA helicase DDX17 was recently reported to modulate HIV-1 RNA stability and export. In this study, we further show that the helicase activity of DDX17 is required for the production of infectious HIV-1 particles. Over expression of the DDX17 mutant DQAD in HEK293 cells reduces the amount of packaged viral genomic RNA and diminishes HIV-1 Gag-Pol frameshift. Altogether, these data demonstrate that DDX17 promotes the production of HIV-1 infectious particles by modulating HIV-1 RNA metabolism.

A HIV-1 Tat mutant protein disrupts HIV-1 Rev function by targeting the DEAD-box RNA helicase DDX1

“…Expression of Nullbasic, HA-tagged DDX1 (HA-DDX1), HA-tagged DDX3 (HA-DDX3), and HA-tagged DDX17 (HA-DDX17) and parental vector (pcDNA3-HA) alone in the Rev-dependent reporter assay observed no or low expression of CA protein ( Figure 3B, left, lane 2, 4, 7, 10 and 13). The levels of CA were greatly increased when Rev was coexpressed with HA-DDX3 ( Figure 3B results seen in previous studies [29,33,39]. Coexpression of Rev with HA-DDX1 ( Figure 3B, left, lane 5) reduced CA expression~25% (p = 0.02) compared to expression of Rev alone ( Figure 3B, left, lane 1).…”

“…Rev is a 116 amino acid protein and can be divided into three discrete function domains. The Rev RNA-binding domain (RBD, amino acids [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] is an arginine-rich motif that serves as the nucleolar localization signal (NLS), which can be recognized by the cellular importin β-like import receptors and nucleophosmin (NPM), also known as B23 [2][3][4][5]. This region also specifically interacts with a stem loop RNA sequence called Rev response element (RRE), which is located within the env gene among unspliced and singly spliced HIV-1 mRNAs [6,7].…”

DDX17 Specifically, and Independently of DDX5, Controls Use of the HIV A4/5 Splice Acceptor Cluster and Is Essential for Efficient Replication of HIV

“…DDX17 has been suggested to be involved in several aspects of HIV replication including interaction with HIV Rev [29] and modulation of Gag processing [27]; however, detailed functional information about its targets of activity and mechanism of action has been absent until now. Previous studies have sought evidence for the role of DDX17 in HIV and there is consensus that it has a significant effect on viral replication.…”

“…DDX17 has been implicated in alternative splicing [24] and found to interact with known splicing factors in in vitro experiments [25], [26]. In addition, DDX17 has been suggested to modulate HIV-1 RNA stability, associating with Rev to promote nuclear export, genomic RNA packaging and Gag-Pol frameshifting [27], [28], [29]. Silencing DDX17 in TZM-bl cells resulted in a reduction in unspliced and spliced HIV transcripts [29].…”

HIV-1 translation and its regulation by cellular factors PKR and PACT

“…The very stable upper part of this structure becomes an effective frameshift stimulatory signal triggering an incomplete translocation of two nucleotides instead of three Marcheschi et al, 2007;Mazauric et al, 2009;Namy et al, 2006;Reil et al, 1993). This programmed change in the reading frame is modulated or enhanced by viral factors such as the TARpolyA RNA and the Tat protein as well as cellular factors such as the eukaryotic release factor 1 and the DEAD-box RNA helicase 17 Gendron et al, 2008;Kobayashi et al, 2010;Lorgeoux et al, 2013). Decreasing the efficiency of the frameshift decreases virus infectivity due to the presence of a genomic RNA packaging enhancer overlapping the Gag-Pol ribosomal frameshift signal.…”