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Interplay between the alpharetroviral Gag protein and SR proteins SF2 and SC35 in the nucleus

Retroviruses are positive-sense, single-stranded RNA viruses that reverse transcribe their RNA genomes into double-stranded DNA for integration into the host cell chromosome. The integrated provirus is used as a template for the transcription of viral RNA. The full-length viral RNA can be used for t...

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Autores principales: Rice, Breanna L., Kaddis, Rebecca J., Stake, Matthew S., Lochmann, Timothy L., Parent, Leslie J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562304/
https://www.ncbi.nlm.nih.gov/pubmed/26441864
http://dx.doi.org/10.3389/fmicb.2015.00925
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author Rice, Breanna L.
Kaddis, Rebecca J.
Stake, Matthew S.
Lochmann, Timothy L.
Parent, Leslie J.
author_facet Rice, Breanna L.
Kaddis, Rebecca J.
Stake, Matthew S.
Lochmann, Timothy L.
Parent, Leslie J.
author_sort Rice, Breanna L.
collection PubMed
description Retroviruses are positive-sense, single-stranded RNA viruses that reverse transcribe their RNA genomes into double-stranded DNA for integration into the host cell chromosome. The integrated provirus is used as a template for the transcription of viral RNA. The full-length viral RNA can be used for the translation of the Gag and Gag-Pol structural proteins or as the genomic RNA (gRNA) for encapsidation into new virions by the Gag protein. The mechanism by which Gag selectively incorporates unspliced gRNA into virus particles is poorly understood. Although Gag was previously thought to localize exclusively to the cytoplasm and plasma membrane where particles are released, we found that the Gag protein of Rous sarcoma virus, an alpharetrovirus, undergoes transient nuclear trafficking. When the nuclear export signal of RSV Gag is mutated (Gag.L219A), the protein accumulates in discrete subnuclear foci reminiscent of nuclear bodies such as splicing speckles, paraspeckles, and PML bodies. In this report, we observed that RSV Gag.L219A foci appeared to be tethered in the nucleus, partially co-localizing with the splicing speckle components SC35 and SF2. Overexpression of SC35 increased the number of Gag.L219A nucleoplasmic foci, suggesting that SC35 may facilitate the formation of Gag foci. We previously reported that RSV Gag nuclear trafficking is required for efficient gRNA packaging. Together with the data presented herein, our findings raise the intriguing hypothesis that RSV Gag may co-opt splicing factors to localize near transcription sites. Because splicing occurs co-transcriptionally, we speculate that this mechanism could allow Gag to associate with unspliced viral RNA shortly after its transcription initiation in the nucleus, before the viral RNA can be spliced or exported from the nucleus as an mRNA template.
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spelling pubmed-45623042015-10-05 Interplay between the alpharetroviral Gag protein and SR proteins SF2 and SC35 in the nucleus Rice, Breanna L. Kaddis, Rebecca J. Stake, Matthew S. Lochmann, Timothy L. Parent, Leslie J. Front Microbiol Microbiology Retroviruses are positive-sense, single-stranded RNA viruses that reverse transcribe their RNA genomes into double-stranded DNA for integration into the host cell chromosome. The integrated provirus is used as a template for the transcription of viral RNA. The full-length viral RNA can be used for the translation of the Gag and Gag-Pol structural proteins or as the genomic RNA (gRNA) for encapsidation into new virions by the Gag protein. The mechanism by which Gag selectively incorporates unspliced gRNA into virus particles is poorly understood. Although Gag was previously thought to localize exclusively to the cytoplasm and plasma membrane where particles are released, we found that the Gag protein of Rous sarcoma virus, an alpharetrovirus, undergoes transient nuclear trafficking. When the nuclear export signal of RSV Gag is mutated (Gag.L219A), the protein accumulates in discrete subnuclear foci reminiscent of nuclear bodies such as splicing speckles, paraspeckles, and PML bodies. In this report, we observed that RSV Gag.L219A foci appeared to be tethered in the nucleus, partially co-localizing with the splicing speckle components SC35 and SF2. Overexpression of SC35 increased the number of Gag.L219A nucleoplasmic foci, suggesting that SC35 may facilitate the formation of Gag foci. We previously reported that RSV Gag nuclear trafficking is required for efficient gRNA packaging. Together with the data presented herein, our findings raise the intriguing hypothesis that RSV Gag may co-opt splicing factors to localize near transcription sites. Because splicing occurs co-transcriptionally, we speculate that this mechanism could allow Gag to associate with unspliced viral RNA shortly after its transcription initiation in the nucleus, before the viral RNA can be spliced or exported from the nucleus as an mRNA template. Frontiers Media S.A. 2015-09-08 /pmc/articles/PMC4562304/ /pubmed/26441864 http://dx.doi.org/10.3389/fmicb.2015.00925 Text en Copyright © 2015 Rice, Kaddis, Stake, Lochmann and Parent. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
Rice, Breanna L.
Kaddis, Rebecca J.
Stake, Matthew S.
Lochmann, Timothy L.
Parent, Leslie J.
Interplay between the alpharetroviral Gag protein and SR proteins SF2 and SC35 in the nucleus
title Interplay between the alpharetroviral Gag protein and SR proteins SF2 and SC35 in the nucleus
title_full Interplay between the alpharetroviral Gag protein and SR proteins SF2 and SC35 in the nucleus
title_fullStr Interplay between the alpharetroviral Gag protein and SR proteins SF2 and SC35 in the nucleus
title_full_unstemmed Interplay between the alpharetroviral Gag protein and SR proteins SF2 and SC35 in the nucleus
title_short Interplay between the alpharetroviral Gag protein and SR proteins SF2 and SC35 in the nucleus
title_sort interplay between the alpharetroviral gag protein and sr proteins sf2 and sc35 in the nucleus
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562304/
https://www.ncbi.nlm.nih.gov/pubmed/26441864
http://dx.doi.org/10.3389/fmicb.2015.00925
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