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HIV‐1 Gag–RNA Interaction Occurs at a Perinuclear/Centrosomal Site; Analysis by Confocal Microscopy and FRET
Author(s) -
Poole Emma,
Strappe Padraig,
Mok HoiPing,
Hicks Ray,
Lever Andrew M L.
Publication year - 2005
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2005.00312.x
Subject(s) - rna , biology , group specific antigen , microbiology and biotechnology , cytoplasm , centriole , rna binding protein , virus , virology , biochemistry , gene
The Gag polyprotein is the major structural protein of human immunodeficiency virus‐1 (HIV‐1) constituting the viral core. Between translation on cytoplasmic polysomes and assembly into viral particles at the plasma membrane, it specifically captures the RNA genome of the virus through binding RNA structural motifs (packaging signals –Ψ) in the RNA. RNA is believed to be a structural facilitator of Gag assembly. Using a combined approach of immunofluorescence detection of Gag protein and in situ hybridisation detection of viral genomic RNA, we demonstrate that Gag protein colocalises early after expression with Ψ+ RNA in the perinuclear region and also colocalises with centrioles. Colocalised RNA and protein subsequently traffic through the cytoplasm to the plasma membrane of the cell. Gag expressed from Ψ– RNA diffuses throughout the cell. It is not found at centrioles and shows delayed cytoplasmic colocalisation with the RNA genome. RNA capture through Ψ does not influence binding of Gag to microfilaments. Gag does not bind to tubulin during export. The presence of the packaging signal may coordinate capture of Ψ+ RNA by Gag protein at the centrosome followed by their combined transport to the site of budding. HIV‐1 Ψ thus acts as a subcellular localisation signal as well as a high‐affinity‐binding site for Gag.