Cargando…

The cooperative function of arginine residues in the Prototype Foamy Virus Gag C-terminus mediates viral and cellular RNA encapsidation

BACKGROUND: One unique feature of the foamy virus (FV) capsid protein Gag is the absence of Cys-His motifs, which in orthoretroviruses are irreplaceable for multitude functions including viral RNA genome recognition and packaging. Instead, FV Gag contains glycine-arginine-rich (GR) sequences at its...

Descripción completa

Detalles Bibliográficos
Autores principales: Hamann, Martin V, Müllers, Erik, Reh, Juliane, Stanke, Nicole, Effantin, Gregory, Weissenhorn, Winfried, Lindemann, Dirk
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4198681/
https://www.ncbi.nlm.nih.gov/pubmed/25292281
http://dx.doi.org/10.1186/s12977-014-0087-7
_version_ 1782339763053789184
author Hamann, Martin V
Müllers, Erik
Reh, Juliane
Stanke, Nicole
Effantin, Gregory
Weissenhorn, Winfried
Lindemann, Dirk
author_facet Hamann, Martin V
Müllers, Erik
Reh, Juliane
Stanke, Nicole
Effantin, Gregory
Weissenhorn, Winfried
Lindemann, Dirk
author_sort Hamann, Martin V
collection PubMed
description BACKGROUND: One unique feature of the foamy virus (FV) capsid protein Gag is the absence of Cys-His motifs, which in orthoretroviruses are irreplaceable for multitude functions including viral RNA genome recognition and packaging. Instead, FV Gag contains glycine-arginine-rich (GR) sequences at its C-terminus. In case of prototype FV (PFV) these are historically grouped in three boxes, which have been shown to play essential functions in genome reverse transcription, virion infectivity and particle morphogenesis. Additional functions for RNA packaging and Pol encapsidation were suggested, but have not been conclusively addressed. RESULTS: Here we show that released wild type PFV particles, like orthoretroviruses, contain various cellular RNAs in addition to viral genome. Unlike orthoretroviruses, the content of selected cellular RNAs in capsids of PFV vector particles was not altered by viral genome encapsidation. Deletion of individual GR boxes had only minor negative effects (2 to 4-fold) on viral and cellular RNA encapsidation over a wide range of cellular Gag to viral genome ratios examined. Only the concurrent deletion of all three PFV Gag GR boxes, or the substitution of multiple arginine residues residing in the C-terminal GR box region by alanine, abolished both viral and cellular RNA encapsidation (>50 to >3,000-fold reduced), independent of the viral production system used. Consequently, those mutants also lacked detectable amounts of encapsidated Pol and were non-infectious. In contrast, particle release was reduced to a much lower extent (3 to 20-fold). CONCLUSIONS: Taken together, our data provides the first identification of a full-length PFV Gag mutant devoid in genome packaging and the first report of cellular RNA encapsidation into PFV particles. Our results suggest that the cooperative action of C-terminal clustered positively charged residues, present in all FV Gag proteins, is the main viral protein determinant for viral and cellular RNA encapsidation. The viral genome independent efficiency of cellular RNA encapsidation suggests differential packaging mechanisms for both types of RNAs. Finally, this study indicates that analogous to orthoretroviruses, Gag – nucleic acid interactions are required for FV capsid assembly and efficient particle release. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12977-014-0087-7) contains supplementary material, which is available to authorized users.
format Online
Article
Text
id pubmed-4198681
institution National Center for Biotechnology Information
language English
publishDate 2014
publisher BioMed Central
record_format MEDLINE/PubMed
spelling pubmed-41986812014-10-17 The cooperative function of arginine residues in the Prototype Foamy Virus Gag C-terminus mediates viral and cellular RNA encapsidation Hamann, Martin V Müllers, Erik Reh, Juliane Stanke, Nicole Effantin, Gregory Weissenhorn, Winfried Lindemann, Dirk Retrovirology Research BACKGROUND: One unique feature of the foamy virus (FV) capsid protein Gag is the absence of Cys-His motifs, which in orthoretroviruses are irreplaceable for multitude functions including viral RNA genome recognition and packaging. Instead, FV Gag contains glycine-arginine-rich (GR) sequences at its C-terminus. In case of prototype FV (PFV) these are historically grouped in three boxes, which have been shown to play essential functions in genome reverse transcription, virion infectivity and particle morphogenesis. Additional functions for RNA packaging and Pol encapsidation were suggested, but have not been conclusively addressed. RESULTS: Here we show that released wild type PFV particles, like orthoretroviruses, contain various cellular RNAs in addition to viral genome. Unlike orthoretroviruses, the content of selected cellular RNAs in capsids of PFV vector particles was not altered by viral genome encapsidation. Deletion of individual GR boxes had only minor negative effects (2 to 4-fold) on viral and cellular RNA encapsidation over a wide range of cellular Gag to viral genome ratios examined. Only the concurrent deletion of all three PFV Gag GR boxes, or the substitution of multiple arginine residues residing in the C-terminal GR box region by alanine, abolished both viral and cellular RNA encapsidation (>50 to >3,000-fold reduced), independent of the viral production system used. Consequently, those mutants also lacked detectable amounts of encapsidated Pol and were non-infectious. In contrast, particle release was reduced to a much lower extent (3 to 20-fold). CONCLUSIONS: Taken together, our data provides the first identification of a full-length PFV Gag mutant devoid in genome packaging and the first report of cellular RNA encapsidation into PFV particles. Our results suggest that the cooperative action of C-terminal clustered positively charged residues, present in all FV Gag proteins, is the main viral protein determinant for viral and cellular RNA encapsidation. The viral genome independent efficiency of cellular RNA encapsidation suggests differential packaging mechanisms for both types of RNAs. Finally, this study indicates that analogous to orthoretroviruses, Gag – nucleic acid interactions are required for FV capsid assembly and efficient particle release. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12977-014-0087-7) contains supplementary material, which is available to authorized users. BioMed Central 2014-10-08 /pmc/articles/PMC4198681/ /pubmed/25292281 http://dx.doi.org/10.1186/s12977-014-0087-7 Text en © Hamann et al.; licensee BioMed Central Ltd. 2014 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Hamann, Martin V
Müllers, Erik
Reh, Juliane
Stanke, Nicole
Effantin, Gregory
Weissenhorn, Winfried
Lindemann, Dirk
The cooperative function of arginine residues in the Prototype Foamy Virus Gag C-terminus mediates viral and cellular RNA encapsidation
title The cooperative function of arginine residues in the Prototype Foamy Virus Gag C-terminus mediates viral and cellular RNA encapsidation
title_full The cooperative function of arginine residues in the Prototype Foamy Virus Gag C-terminus mediates viral and cellular RNA encapsidation
title_fullStr The cooperative function of arginine residues in the Prototype Foamy Virus Gag C-terminus mediates viral and cellular RNA encapsidation
title_full_unstemmed The cooperative function of arginine residues in the Prototype Foamy Virus Gag C-terminus mediates viral and cellular RNA encapsidation
title_short The cooperative function of arginine residues in the Prototype Foamy Virus Gag C-terminus mediates viral and cellular RNA encapsidation
title_sort cooperative function of arginine residues in the prototype foamy virus gag c-terminus mediates viral and cellular rna encapsidation
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4198681/
https://www.ncbi.nlm.nih.gov/pubmed/25292281
http://dx.doi.org/10.1186/s12977-014-0087-7
work_keys_str_mv AT hamannmartinv thecooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT mullerserik thecooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT rehjuliane thecooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT stankenicole thecooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT effantingregory thecooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT weissenhornwinfried thecooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT lindemanndirk thecooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT hamannmartinv cooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT mullerserik cooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT rehjuliane cooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT stankenicole cooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT effantingregory cooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT weissenhornwinfried cooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation
AT lindemanndirk cooperativefunctionofarginineresiduesintheprototypefoamyvirusgagcterminusmediatesviralandcellularrnaencapsidation