DDX5 Facilitates HIV-1 Replication as a Cellular Co-Factor of Rev

Xiuxia Zhou,Shuangxin Wu,Ting Pan,Hui Zhang,Haihua Luo,Lisa Mills,Guannan Geng,Juan Luo,Chao Liu,Jim Zhang,Jean-Pierre Vartanian

doi:10.1371/journal.pone.0065040

Abstract

HIV-1 Rev plays an important role in the late phase of HIV-1 replication, which facilitates export of unspliced viral mRNAs from the nucleus to cytoplasm in infected cells. Recent studies have shown that DDX1 and DDX3 are co-factors of Rev for the export of HIV-1 transcripts. In this report, we have demonstrated that DDX5 (p68), which is a multifunctional DEAD-box RNA helicase, functions as a new cellular co-factor of HIV-1 Rev. We found that DDX5 affects Rev function through the Rev-RRE axis and subsequently enhances HIV-1 replication. Confocal microscopy and co-immunoprecipitation analysis indicated that DDX5 binds to Rev and this interaction is largely dependent on RNA. If the DEAD-box motif of DDX5 is mutated, DDX5 loses almost all of its ability to bind to Rev, indicating that the DEAD-box motif of DDX5 is required for the interaction between DDX5 and Rev. Our data indicate that interference of DDX5-Rev interaction could reduce HIV-1 replication and potentially provide a new molecular target for anti-HIV-1 therapeutics.

Highlights

The Rev protein of human immunodeficiency virus type 1 (HIV-1) is a 19 kDa protein produced from fully spliced mRNA in the early phase of HIV-1 gene expression, and functions as a nucleocytoplasmic shuttling phosphoprotein [1]
As DDX5 belongs to the DEAD-box RNA helicase family, we hypothesized that DDX5 could function as a co-factor in HIV-1 replication
Compared to the vector control, DDX5 enhanced the production of HIV-1 p24 significantly and this increase correlated with the expression level of DDX5 (Fig. 1C)

Summary

Introduction

The Rev protein of human immunodeficiency virus type 1 (HIV-1) is a 19 kDa protein produced from fully spliced mRNA in the early phase of HIV-1 gene expression, and functions as a nucleocytoplasmic shuttling phosphoprotein [1]. Rev is a key regulator of HIV-1 replication because it enables the transition from the early phase of gene expression to the late phase [2,3]. Binding to unspliced and incompletely spliced HIV-1 transcripts and shuttling of these mRNAs from the nucleus to cytoplasm are the best-characterized function of Rev [4]. The efficient export of nuclear/cytoplasmic RNA is accomplished by binding to the Rev Response Element (RRE) within these mRNAs [5]. In addition to the export of unspliced or incompletely spliced mRNA, Rev enhances their translation and increases the half-life of RREcontaining mRNAs in the nucleus [3]

Methods

Results

Conclusion