This work was supported by grants from CONACyT-SEP (SEP-2008-84582; CB-2011-01-168497) and Promep-SEP for R.A.G.; P.H. received a scholarship from CONACyT (447442).

1. HFF Cell Culture and Ad-infection
<ol>
	<li>Propagate Ad5 WT virus in monolayers of HEK-293 cells and titer as fluorescent forming units (FFU) on HFF cells as described previously8.</li>
	<li>Grow Human Foreskin fibroblasts (HFF) in 10 ml of DMEM/10% Fetal Bovine Serum (FBS) in sterile culture 100 mm dishes at 37 &#186;C and 5% CO2 in a humidified incubator. Determine the cell number using a Neubauer chamber by counting cells in the four 16-square sets. The cell number per ml is obtained by cal...

<ol>
	<li>Doucas, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenovirus+replication+is+coupled+with+the+dynamic+properties+of+the+PML+nuclear+structure.">Adenovirus replication is coupled with the dynamic properties of the PML nuclear structure.</a> Genes &#38; Dev. 10, 196-207 (1996).</li><li>Schmid, M., Speiseder, T., Dobner, T., Gonzalez, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=DNA+virus+replication+compartments.">DNA virus replication compartments.</a> J. Virol. 88, 1404-1420 (2014).</li><li>Boon, J. A., Diaz, A., Ahlquist, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytoplasmic+viral+replication+complexes.">Cytoplasmic viral replication complexes.</a> Cell host microbe. 8, 77-85 (2010).</li><li>Paul, D., Hoppe, S., Saher, G., Krijnse-Locker, J., Bartenschlager, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphological+and+biochemical+characterization+of+the+membranous+hepatitis+C+virus+replication+compartment.">Morphological and biochemical characterization of the membranous hepatitis C virus replication compartment.</a> J. Virol. 87, 10612-10627 (2013).</li><li>Busch, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+Nucleoli.">Isolation of Nucleoli.</a> Exp Cell Res. 24, 150-163 (1963).</li><li>Lam, Y. W., Lyon, C. E., Lamond, A. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Large-scale+isolation+of+Cajal+bodies+from+HeLa+cells.">Large-scale isolation of Cajal bodies from HeLa cells.</a> Mol. Biol. Cell. 13, 2461-2473 (2002).</li><li>Lam, Y. W., Trinkle-Mulcahy, L., Lamond, A. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+nucleolus.">The nucleolus.</a> J Cell Sci. 118, 1335-1337 (2005).</li><li>Groitl, P., Dobner, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction+of+adenovirus+type+5+early+region+1+and+4+virus+mutants.">Construction of adenovirus type 5 early region 1 and 4 virus mutants.</a> Methods Mol Med. 130, 29-39 (2007).</li><li>Reich, N. C., Sarnow, P., Duprey, E., Levine, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monoclonal+antibodies+which+recognize+native+and+denatured+forms+of+the+adenovirus+DNA-binding+protein.">Monoclonal antibodies which recognize native and denatured forms of the adenovirus DNA-binding protein.</a> Virology. 128, 480-484 (1983).</li><li>Leppard, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+effects+on+adenovirus+late+gene+expression+of+deleting+the+E1b+55K+protein.">Selective effects on adenovirus late gene expression of deleting the E1b 55K protein.</a> J Gen Virol. 74 (Pt 4), 575-582 (1993).</li><li>Gonzalez, R., Huang, W., Finnen, R., Bragg, C., Flint, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenovirus+E1B+55-kilodalton+protein+is+required+for+both+regulation+of+mRNA+export+and+efficient+entry+into+the+late+phase+of+infection+in+normal+human+fibroblasts.">Adenovirus E1B 55-kilodalton protein is required for both regulation of mRNA export and efficient entry into the late phase of infection in normal human fibroblasts.</a> J. Virol. 80, 964-974 (2006).</li><li>Castillo-Villanueva, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Mre11+Cellular+Protein+Is+Modified+by+Conjugation+of+Both+SUMO-1+and+SUMO-2/3+during+Adenovirus+Infection.">The Mre11 Cellular Protein Is Modified by Conjugation of Both SUMO-1 and SUMO-2/3 during Adenovirus Infection.</a> ISRN Virology. 2014, 14 (2014).</li><li>Morris, S. J., Scott, G. E., Leppard, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenovirus+late-phase+infection+is+controlled+by+a+novel+L4+promoter.">Adenovirus late-phase infection is controlled by a novel L4 promoter.</a> J. Virol. 84, 7096-7104 (2010).</li><li>Wright, J., Leppard, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+human+adenovirus+5+L4+promoter+is+activated+by+cellular+stress+response+protein+p53.">The human adenovirus 5 L4 promoter is activated by cellular stress response protein p53.</a> J. Virol. 87, 11617-11625 (2013).</li></ol>

The authors have nothing to disclose.

In order to elucidate the molecular mechanisms that govern regulation of cellular activities by viral infection understanding the composition and activities associated with RC would be instrumental. Therefore, to make a detailed analysis of RC, we established a cell-free system that takes advantage of the size and biochemical composition of these virus-induced structures, to isolate subnuclear fractions enriched with RC using a simple procedure that relies on velocity gradients with sucrose cushions. Critical steps of th...

Adenoviruses contain a double-stranded DNA genome that replicates in the infected cell nucleus. When the viral DNA enters the nucleus, it localizes adjacent to PML nuclear bodies1. Following viral early gene expression, the nuclear architecture is dramatically reorganized, inducing formation of viral microenvironments, termed viral Replication Compartments (RC)2. Since adenovirus (Ad) RC are sites where viral genome replication and expression of viral late genes take place, they provide an environment for recruitment of all the necessary viral and cellular factors that participate in these processes. Interestingly, a variety of cellular proteins responsible for the cellular antiviral response, such as the DNA damage response, the innate immune response and tumor suppression are co-opted to these viral sites2. Hence, Ad RC can be considered regulatory hubs that promote efficient viral replication while concomitantly regulating the cellular antiviral response, indicating that these structures are key to the understanding of virus-host cell interactions. Nevertheless, the molecular mechanisms of RC formation, their composition and associated activities are poorly understood.
Adenoviral RC, as well as RC from other DNA viruses that replicate in the nucleus are not associated to membranes, in contrast to cytoplasmic RC3. Moreover, these virus-induced structures are likely to be composed entirely of proteins and nucleic acids. RC formed in cells infected with RNA viruses (usually termed viral factories) have been isolated, taking advantage of their cytoplasmic localization and membrane-bound status, which has facilitated their detailed morphological, functional and biochemical characterization4.
To our knowledge, nuclear viral RC have not been isolated, perhaps due to the complexity of the nuclear architecture and absence of intranuclear membranes that would facilitate their isolation. Their study has relied instead on immunofluorescence microscopy, FISH and transmission electron microscopy. However, despite complications inherent to isolating subnuclear structures, other nuclear domains such as nucleoli and Cajal Bodies have been isolated before 5,6. Since nucleoli and RC are both composed of proteins and nucleic acids, and have a diameter between 0.5 - 5 &#181;m, we hypothesized that RC should also be amenable to isolation. Therefore, in order to more precisely characterize the molecular composition and functions associated to RC, we established a novel method to isolate subnuclear fractions enriched with RC. To this end, we prepared sub-nuclear fractions using velocity gradients and sucrose cushions similar to procedures used to isolate nucleoli7 or other nuclear domains6 and established a cell-free system that allows the study of the molecular composition and associated activities of RC. This technique should therefore advance the understanding of virus-host cell interactions and represents a powerful tool that should also facilitate the detailed analysis of RC from other viruses that replicate in the nucleus and induce formation of replication compartments of similar dimensions to those formed in adenovirus-infected-cells, such as, herpesviruses, papillomaviruses or polyomaviruses.

<table border="0">
	<tbody>
		<tr>
			<td>DMEM</td>
			<td>Gibco</td>
			<td>12100-046</td>
			<td>Warm in 37 &#186;C water bath before use</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Gibco</td>
			<td>12484-028</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose, Ultra Pure</td>
			<td>Research Organics</td>
			<td>0928S</td>
			<td>Prepare a 2.55 M stock solution and store at 4 &#186;C</td>
		</tr>
		<tr>
			<td>Dounce homogenizer</td>
			<td>Kontess Glass Company</td>
			<td>884900-0000</td>
			<td></td>
		</tr>
		<tr>
			<td>Branson 1800 Ultrasonic Bath</td>
			<td>Branson</td>
			<td>Z769533&#160;SIGMA</td>
			<td>Turn on 15 min before use.</td>
		</tr>
		<tr>
			<td>Peroxidase AffiniPure F(ab&#39;)&#8322; Fragment Goat Anti-Mouse IgG (H+L)</td>
			<td>Jackson ImmunoResearch</td>
			<td>115-036-003</td>
			<td>Use at a 1:10,000 dilution in PBS/0.03% non-fat milk</td>
		</tr>
		<tr>
			<td>Goat anti-Mouse IgG1 Secondary Antibody, Alexa Fluor 488 conjugate</td>
			<td>Life Technologies</td>
			<td>A-21121</td>
			<td>Use at a 1:2,000 dilution in PBS</td>
		</tr>
		<tr>
			<td>Silane-Prep Slides</td>
			<td>Sigma</td>
			<td>S4651-72EA</td>
			<td>Open in a laminar flow cabinet</td>
		</tr>
		<tr>
			<td>SuperSignal West Pico Chemiluminescent Substrate</td>
			<td>Pierce ThermoScientific</td>
			<td>34080</td>
			<td></td>
		</tr>
	</tbody>
</table>

isolation of viral replication compartment-enriched sub-nuclear fractions from adenovirus-infected normal human cells

During infection of human cells by adenovirus (Ad), the host cell nucleus is dramatically reorganized, leading to formation of nuclear microenvironments through the recruitment of viral and cellular proteins to sites occupied by the viral genome. These sites, called replication compartments (RC), can be considered viral-induced nuclear domains where the viral genome is localized and viral and cellular proteins that participate in replication, transcription and post-transcriptional processing are recruited. Moreover, cellular proteins involved in the antiviral response, such as tumor suppressor proteins, DNA damage response (DDR) components and innate immune response factors are also co-opted to RC. Although RC seem to play a crucial role to promote an efficient and productive replication cycle, a detailed analysis of their composition and associated activities has not been made. To facilitate the study of adenoviral RC and potentially those from other DNA viruses that replicate in the cell nucleus, we adapted a simple procedure based on velocity gradients to isolate Ad RC and established a cell-free system amenable to conduct morphological, functional and compositional studies of these virus-induced subnuclear structures, as well as to study their impact on host-cell interactions.

Since viral replication compartments (RC) are subnuclear viral-induced structures composed of proteins and nucleic acids, similar to other nuclear domains, they proved to be amenable to isolation by velocity gradients based on biochemical features. Critical steps in the fractionation protocol are illustrated in Figure 1. At each step the samples need to be monitored by bright field microscopy to ensure integrity of the different sub-cellular fractions. For example, when swelling the cells, incubation tim...

Watch this Scientific Journal Video about Isolation of Viral Replication Compartment-enriched Sub-nuclear Fractions from Adenovirus-infected Normal Human Cells at JoVE.com

Isolation of Viral Replication Compartment-enriched Sub-nuclear Fractions from Adenovirus-infected Normal Human Cells

We provide a novel strategy to isolate viral replication compartments (RC) from adenovirus (Ad)-infected human cells. This approach represents a cell-free system that can help to elucidate the molecular mechanisms regulating viral genome replication and expression as well as regulation of viral-host interactions established at the RC.

During infection of human cells by adenovirus (Ad), the host cell nucleus is dramatically reorganized, leading to formation of nuclear microenvironments ...

isolation-viral-replication-compartment-enriched-sub-nuclear

Research

JoVE Journal

Immunology and Infection

8.7K visualizações.  Universidad Autónoma del Estado de Morelos. We provide a novel strategy to isolate viral replication compartments (RC) from adenovirus (Ad)-infected human cells. This approach represents a cell-free system that can help to elucidate the molecular mechanisms regulating viral genome replication and expression as well as regulation of viral-host interactions established at the RC. 