A nucleolar localizing Rev binding element inhibits HIV replication

Alessandro Michienzi,Irene Bozzoni,Fernanda G De Angelis,John J Rossi

doi:10.1186/1742-6405-3-13

Abstract

The Rev protein of the human immunodeficiency virus (HIV) facilitates the nuclear export of intron containing viral mRNAs allowing formation of infectious virions. Rev traffics through the nucleolus and shuttles between the nucleus and cytoplasm. Rev multimerization and interaction with the export protein CRM1 takes place in the nucleolus. To test the importance of Rev nucleolar trafficking in the HIV-1 replication cycle, we created a nucleolar localizing Rev Response Element (RRE) decoy and tested this for its anti-HIV activity. The RRE decoy provided marked inhibition of HIV-1 replication in both the CEM T-cell line and in primary CD34+ derived monocytes. These results demonstrate that titration of Rev in the nucleolus impairs HIV-1 replication and supports a functional role for Rev trafficking in this sub-cellular compartment.

Highlights

human immunodeficiency virus (HIV)-1 gene expression is finely regulated [1]
While the fully spliced RNAs are exported to the cytoplasm, where they are translated into the regulatory and accessory proteins, the late structural proteins and reverse transcriptase (RT) are derived from unspliced or singly spliced RNAs which are transported to the cytoplasm only upon binding of Rev to the Rev Responsive Element (RRE), which is contained in the env coding region [1]
The Rev binding element (RBE) domain is located within the Rev responsive element (RRE) sequence

Summary

Introduction

HIV-1 gene expression is finely regulated [1]. Transcription from the HIV-1 long terminal repeat (LTR) produces a full length RNA of 9 Kb from which several mRNAs are generated by splicing (the 4 Kb singly spliced and 2 Kb fully spliced RNAs) [1]. Rev is an 18kDa protein that localizes to both the nucleus and nucleolus [2,3,4] It contains a nuclear export signal (NES) as well as a nuclear import signal (NLS) that allow nuclear/nucleolus-cytoplasmic shuttling properties [5,6]. By the use of in vivo fluorescence resonance energy transfer (FRET), multimerization of Rev-GFP and BFP fusion proteins has been shown to occur in the nucleoli of HeLa cells [10]. These observations suggest that the nucleolar trafficking of Rev may be critical for Rev mediated export. To test this hypothesis we used a nucleolar localized decoy that contains the Rev binding element (RBE) [11,12,13,14] to sequester Rev within this sub-cellular compartment and test its ability to (page number not for citation purposes)

Methods

Results

Conclusion