Nuclear Factor 90, a cellular dsRNA binding protein inhibits the HIV Rev-export function

Urcuqui-Inchima Silvio, Castaño Maria, Hernandez-Verdun Danièle, St-Laurent Georges, Kumar, Kumar Ajit

Description

The HIV Rev protein is known to facilitate export of incompletely spliced and unspliced viral transcripts to the cytoplasm, a necessary step in virus life cycle. The Rev-mediated nucleo-cytoplasmic transport of nascent viral transcripts, dependents on interaction of Rev with the RRE RNA structural element present in the target RNAs. The C-terminal variant of dsRNA-binding nuclear protein 90 (NF90ctv) has been shown to markedly attenuate viral replication in stably transduced HIV-1 target cell line. Here we examined a mechanism of interference of viral life cycle involving Rev-NF90ctv interaction. Results Since Rev:RRE complex formations depend on protein:RNA and protein:protein interactions, we investigated whether the expression of NF90ctv might interfere with Rev-mediated export of RRE-containing transcripts. When HeLa cells expressed both NF90ctv and Rev protein, we observed that NF90ctv inhibited the Rev-mediated RNA transport. In particular, three regions of NF90ctv protein are involved in blocking Rev function. Moreover, interaction of NF90ctv with the RRE RNA resulted in the expression of a reporter protein coding sequences linked to the RRE structure. Moreover, Rev influenced the subcellular localization of NF90ctv, and this process is leptomycin B sensitive. Conclusion The dsRNA binding protein, NF90ctv competes with HIV Rev function at two levels, by competitive protein:protein interaction involving Rev binding to specific domains of NF90ctv, as well as by its binding to the RRE-RNA structure. Our results are consistent with a model of Rev-mediated HIV-1 RNA export that envisions Rev-multimerization, a process interrupted by NF90ctv.

Informations

• Publié par: biomed
• Publié le: 01 janvier 2006
• Nombre de lectures: 13
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

Retrovirology

BioMedCentral

Open Access Research Nuclear Factor 90, a cellular dsRNA binding protein inhibits the HIV Revexport function 1 1 Silvio UrcuquiInchima* , Maria Eugenia Castaño , Danièle Hernandez 2 3 3 Verdun , Georges StLaurent III and Ajit Kumar

1 2 Address: Grupo de Inmunovirología, Corporación Biogénesis, Universidad de Antioquia, A.A. 1226, Medellín, Colombia, Institut Jacques 3 Monod, CNRS, University Paris VI and Paris VII, 2 place Jussieu, 75251 Paris Cedex 05, France and Department of Biochemistry and Molecular Biology, The George Washington University, Washington, D.C. 20037, USA Email: Silvio UrcuquiInchima*  [e-mail]; Maria Eugenia Castaño  [e-mail]; Danièle Hernandez Verdun  [e-mail]; Georges StLaurent  [e-mail]; Ajit Kumar  [e-mail] * Corresponding author

Published: 24 November 2006 Received: 01 September 2006 Accepted: 24 November 2006 Retrovirology2006,3:83 doi:10.1186/17424690383 This article is available from: http://www.retrovirology.com/content/3/1/83 © 2006 UrcuquiInchima et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract Background:The HIV Rev protein is known to facilitate export of incompletely spliced and unspliced viral transcripts to the cytoplasm, a necessary step in virus life cycle. The Revmediated nucleocytoplasmic transport of nascent viral transcripts, dependents on interaction of Rev with the RRE RNA structural element present in the target RNAs. The Cterminal variant of dsRNA binding nuclear protein 90 (NF90ctv) has been shown to markedly attenuate viral replication in stably transduced HIV1 target cell line. Here we examined a mechanism of interference of viral life cycle involving RevNF90ctv interaction.

Results:Since Rev:RRE complex formations depend on protein:RNA and protein:protein interactions, we investigated whether the expression of NF90ctv might interfere with Rev mediated export of RREcontaining transcripts. When HeLa cells expressed both NF90ctv and Rev protein, we observed that NF90ctv inhibited the Revmediated RNA transport. In particular, three regions of NF90ctv protein are involved in blocking Rev function. Moreover, interaction of NF90ctv with the RRE RNA resulted in the expression of a reporter protein coding sequences linked to the RRE structure. Moreover, Rev influenced the subcellular localization of NF90ctv, and this process is leptomycin B sensitive.

Conclusion:The dsRNA binding protein, NF90ctv competes with HIV Rev function at two levels, by competitive protein:protein interaction involving Rev binding to specific domains of NF90ctv, as well as by its binding to the RRERNA structure. Our results are consistent with a model of Rev mediated HIV1 RNA export that envisions Revmultimerization, a process interrupted by NF90ctv.

Background Upon entering an uninfected host cell, the singlestranded RNA genome of Human immunodeficiency virus type 1 (HIV1) is copied into DNA by the viral reverse tran

scriptase. Following integration of DNA into the host genome, transcriptional activation of the proviral DNA generates progeny virions. The postintegration events of transcription, RNA splicing, transport and translation of

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