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Identification of low molecular weight nuclear complexes containing integrase during the early stages of HIV-1 infection
BACKGROUND: HIV-1 replication requires integration of its reverse transcribed viral cDNA into a host cell chromosome. The DNA cutting and joining reactions associated to this key step are catalyzed by the viral protein integrase (IN). In infected cells, IN binds the viral cDNA, together with viral a...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3571920/ https://www.ncbi.nlm.nih.gov/pubmed/23369367 http://dx.doi.org/10.1186/1742-4690-10-13 |
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author | Gérard, Annabelle Soler, Nicolas Ségéral, Emmanuel Belshan, Michael Emiliani, Stéphane |
author_facet | Gérard, Annabelle Soler, Nicolas Ségéral, Emmanuel Belshan, Michael Emiliani, Stéphane |
author_sort | Gérard, Annabelle |
collection | PubMed |
description | BACKGROUND: HIV-1 replication requires integration of its reverse transcribed viral cDNA into a host cell chromosome. The DNA cutting and joining reactions associated to this key step are catalyzed by the viral protein integrase (IN). In infected cells, IN binds the viral cDNA, together with viral and cellular proteins, to form large nucleoprotein complexes. However, the dynamics of IN complexes formation is still poorly understood. RESULTS: Here, we characterized IN complexes during the early stages of T-lymphocyte infection. We found that following viral entry into the host cell, IN was rapidly targeted to proteasome-mediated degradation. Interactions between IN and cellular cofactors LEDGF/p75 and TNPO3 were detected as early as 6 h post-infection. Size exclusion chromatography of infected cell extracts revealed distinct IN complexes in vivo. While at 2 h post-infection the majority of IN eluted within a high molecular weight complex competent for integration (IN complex I), IN was also detected in a low molecular weight complex devoid of full-length viral cDNA (IN complex II, ~440 KDa). At 6 h post-infection the relative proportion of IN complex II increased. Inhibition of reverse transcription or integration did not alter the elution profile of IN complex II in infected cells. However, in cells depleted for LEDGF/p75 IN complex II shifted to a lower molecular weight complex (IN complex III, ~150 KDa) containing multimers of IN. Notably, cell fractionation experiments indicated that both IN complex II and III were exclusively nuclear. Finally, IN complex II was not detected in cells infected with a virus harboring a mutated IN defective for LEDGF/p75 interaction and tetramerization. CONCLUSIONS: Our findings indicate that, shortly after viral entry, a significant portion of DNA–free IN that is distinct from active pre-integration complexes accumulates in the nucleus. |
format | Online Article Text |
id | pubmed-3571920 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-35719202013-02-14 Identification of low molecular weight nuclear complexes containing integrase during the early stages of HIV-1 infection Gérard, Annabelle Soler, Nicolas Ségéral, Emmanuel Belshan, Michael Emiliani, Stéphane Retrovirology Research BACKGROUND: HIV-1 replication requires integration of its reverse transcribed viral cDNA into a host cell chromosome. The DNA cutting and joining reactions associated to this key step are catalyzed by the viral protein integrase (IN). In infected cells, IN binds the viral cDNA, together with viral and cellular proteins, to form large nucleoprotein complexes. However, the dynamics of IN complexes formation is still poorly understood. RESULTS: Here, we characterized IN complexes during the early stages of T-lymphocyte infection. We found that following viral entry into the host cell, IN was rapidly targeted to proteasome-mediated degradation. Interactions between IN and cellular cofactors LEDGF/p75 and TNPO3 were detected as early as 6 h post-infection. Size exclusion chromatography of infected cell extracts revealed distinct IN complexes in vivo. While at 2 h post-infection the majority of IN eluted within a high molecular weight complex competent for integration (IN complex I), IN was also detected in a low molecular weight complex devoid of full-length viral cDNA (IN complex II, ~440 KDa). At 6 h post-infection the relative proportion of IN complex II increased. Inhibition of reverse transcription or integration did not alter the elution profile of IN complex II in infected cells. However, in cells depleted for LEDGF/p75 IN complex II shifted to a lower molecular weight complex (IN complex III, ~150 KDa) containing multimers of IN. Notably, cell fractionation experiments indicated that both IN complex II and III were exclusively nuclear. Finally, IN complex II was not detected in cells infected with a virus harboring a mutated IN defective for LEDGF/p75 interaction and tetramerization. CONCLUSIONS: Our findings indicate that, shortly after viral entry, a significant portion of DNA–free IN that is distinct from active pre-integration complexes accumulates in the nucleus. BioMed Central 2013-02-01 /pmc/articles/PMC3571920/ /pubmed/23369367 http://dx.doi.org/10.1186/1742-4690-10-13 Text en Copyright ©2013 Gérard et al.; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 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. |
spellingShingle | Research Gérard, Annabelle Soler, Nicolas Ségéral, Emmanuel Belshan, Michael Emiliani, Stéphane Identification of low molecular weight nuclear complexes containing integrase during the early stages of HIV-1 infection |
title | Identification of low molecular weight nuclear complexes containing integrase during the early stages of HIV-1 infection |
title_full | Identification of low molecular weight nuclear complexes containing integrase during the early stages of HIV-1 infection |
title_fullStr | Identification of low molecular weight nuclear complexes containing integrase during the early stages of HIV-1 infection |
title_full_unstemmed | Identification of low molecular weight nuclear complexes containing integrase during the early stages of HIV-1 infection |
title_short | Identification of low molecular weight nuclear complexes containing integrase during the early stages of HIV-1 infection |
title_sort | identification of low molecular weight nuclear complexes containing integrase during the early stages of hiv-1 infection |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3571920/ https://www.ncbi.nlm.nih.gov/pubmed/23369367 http://dx.doi.org/10.1186/1742-4690-10-13 |
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