Cytoplasmic utilization of human immunodeficiency virus type 1 genomic RNA is not dependent on a nuclear interaction with gag.

Abstract:

:In some retroviruses, such as Rous sarcoma virus and prototype foamy virus, Gag proteins are known to shuttle between the nucleus and the cytoplasm and are implicated in nuclear export of the viral genomic unspliced RNA (gRNA) for subsequent encapsidation. A similar function has been proposed for human immunodeficiency virus type 1 (HIV-1) Gag based on the identification of nuclear localization and export signals. However, the ability of HIV-1 Gag to transit through the nucleus has never been confirmed. In addition, the lentiviral Rev protein promotes efficient nuclear gRNA export, and previous reports indicate a cytoplasmic interaction between Gag and gRNA. Therefore, functional effects of HIV-1 Gag on gRNA and its usage were explored. Expression of gag in the absence of Rev was not able to increase cytoplasmic gRNA levels of subgenomic, proviral, or lentiviral vector constructs, and gene expression from genomic reporter plasmids could not be induced by Gag provided in trans. Furthermore, Gag lacking the reported nuclear localization and export signals was still able to mediate an efficient packaging process. Although small amounts of Gag were detectable in the nuclei of transfected cells, a Crm1-dependent nuclear export signal in Gag could not be confirmed. Thus, our study does not provide any evidence for a nuclear function of HIV-1 Gag. The encapsidation process of HIV-1 therefore clearly differs from that of Rous sarcoma virus and prototype foamy virus.

journal_name

J Virol

journal_title

Journal of virology

authors

Grewe B,Hoffmann B,Ohs I,Blissenbach M,Brandt S,Tippler B,Grunwald T,Uberla K

doi

10.1128/JVI.06874-11

subject

Has Abstract

pub_date

2012-03-01 00:00:00

pages

2990-3002

issue

6

eissn

0022-538X

issn

1098-5514

pii

JVI.06874-11

journal_volume

86

pub_type

杂志文章