Name: detection of human immunodeficiency virus type 1 (hiv-1) antisense protein (asp) rna transcripts in patients by strand-specific rt-pcr
Uploaded: 2019-11-27T14:00:00
Description: Watch this Scientific Journal Video about Detection of Human Immunodeficiency Virus Type 1 HIV-1 Antisense Protein ASP RNA Transcripts in Patients by Strand-Specific RT-PCR at JoVE.com

We thank Patrizia Amelio, Alessandra Noto, Craig Fenwick, and Matthieu Perreau for always being available to discuss our work and all the people in the Laboratory of AIDS Immunopathogenesis for their precious technical assistance. We also would like to thank John and Aaron Weddle from VSB Associated Inc. who contributed with excellent artwork. Finally, many special thanks to all the Patients, without whom this work would not have been possible. This work received no specific grant from any funding agency.

This study was approved by the Institutional Review Board of the Centre Hospitalier Universitaire Vaudois (CHUV).
1. Infection of peripheral blood mononuclear cells (PBMCs) with HIV-1HXB2 strain
<ol>
	<li>Day 1: PBMCs STIMULATION
	<ol>
		<li>Isolate PBMCs from a healthy donor buffy coat.</li>
		<li>Count and resuspend PBMCs at a concentration of 1x106/mL in complete Roswell Park Memorial Institute (RPMI) 1640 medium containing 10% fetal bovine serum (FB...

<ol>
	<li>Miller, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+immunodeficiency+virus+may+encode+a+novel+protein+on+the+genomic+DNA+plus+strand.">Human immunodeficiency virus may encode a novel protein on the genomic DNA plus strand.</a> Science. 239 (4846), 1420-1422 (1988).</li><li>Vanheebrossollet, C., 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=A+Natural+Antisense+Rna+Derived+from+the+Hiv-1+Env+Gene+Encodes+a+Protein+Which+Is+Recognized+by+Circulating+Antibodies+of+Hiv++Individuals.">A Natural Antisense Rna Derived from the Hiv-1 Env Gene Encodes a Protein Which Is Recognized by Circulating Antibodies of Hiv+ Individuals.</a> Virology. 206 (1), 196-202 (1995).</li><li>Briquet, S., Vaquero, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunolocalization+studies+of+an+antisense+protein+in+HIV-1-infected+cells+and+viral+particles.">Immunolocalization studies of an antisense protein in HIV-1-infected cells and viral particles.</a> Virology. 292 (2), 177-184 (2002).</li><li>Clerc, I., 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=Polarized+expression+of+the+membrane+ASP+protein+derived+from+HIV-1+antisense+transcription+in+T+cells.">Polarized expression of the membrane ASP protein derived from HIV-1 antisense transcription in T cells.</a> Retrovirology. 8, 74 (2011).</li><li>Landry, S., 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=Detection,+characterization+and+regulation+of+antisense+transcripts+in+HIV-1.">Detection, characterization and regulation of antisense transcripts in HIV-1.</a> Retrovirology. 4, 71 (2007).</li><li>Kobayashi-Ishihara, M., 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=HIV-1-encoded+antisense+RNA+suppresses+viral+replication+for+a+prolonged+period.">HIV-1-encoded antisense RNA suppresses viral replication for a prolonged period.</a> Retrovirology. 9, 38 (2012).</li><li>Barbagallo, M. S., Birch, K. E., Deacon, N. J., Mosse, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Potential+control+of+human+immunodeficiency+virus+type+1+asp+expression+by+alternative+splicing+in+the+upstream+untranslated+region.">Potential control of human immunodeficiency virus type 1 asp expression by alternative splicing in the upstream untranslated region.</a> DNA Cell Biol. 31 (7), 1303-1313 (2012).</li><li>Laverdure, S., 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=HIV-1+Antisense+Transcription+Is+Preferentially+Activated+in+Primary+Monocyte-Derived+Cells.">HIV-1 Antisense Transcription Is Preferentially Activated in Primary Monocyte-Derived Cells.</a> Journal of Virology. 86 (24), 13785-13789 (2012).</li><li>Zapata, J. C., 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+Human+Immunodeficiency+Virus+1+ASP+RNA+promotes+viral+latency+by+recruiting+the+Polycomb+Repressor+Complex+2+and+promoting+nucleosome+assembly.">The Human Immunodeficiency Virus 1 ASP RNA promotes viral latency by recruiting the Polycomb Repressor Complex 2 and promoting nucleosome assembly.</a> Virology. 506, 34-44 (2017).</li><li>Haist, K., Ziegler, C., Botten, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strand-Specific+Quantitative+Reverse+Transcription-Polymerase+Chain+Reaction+Assay+for+Measurement+of+Arenavirus+Genomic+and+Antigenomic+RNAs.">Strand-Specific Quantitative Reverse Transcription-Polymerase Chain Reaction Assay for Measurement of Arenavirus Genomic and Antigenomic RNAs.</a> PLoS One. 10 (5), 0120043 (2015).</li><li>Lerat, 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=Specific+detection+of+hepatitis+C+virus+minus+strand+RNA+in+hematopoietic+cells.">Specific detection of hepatitis C virus minus strand RNA in hematopoietic cells.</a> The Journal of Clinical Investigation. 97 (3), 845-851 (1996).</li><li>Tuiskunen, A., 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=Self-priming+of+reverse+transcriptase+impairs+strand-specific+detection+of+dengue+virus+RNA.">Self-priming of reverse transcriptase impairs strand-specific detection of dengue virus RNA.</a> J Gen Virol. 91, 1019-1027 (2010).</li><li>Mancarella, A., 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=Detection+of+antisense+protein+(ASP)+RNA+transcripts+in+individuals+infected+with+human+immunodeficiency+virus+type+1+(HIV-1).">Detection of antisense protein (ASP) RNA transcripts in individuals infected with human immunodeficiency virus type 1 (HIV-1).</a> Journal of General Virology. , (2019).</li><li>Peyrefitte, C. N., Pastorino, B., Bessaud, M., Tolou, H. J., Couissinier-Paris, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evidence+for+in+vitro+falsely-primed+cDNAs+that+prevent+specific+detection+of+virus+negative+strand+RNAs+in+dengue-infected+cells:+improvement+by+tagged+RT-PCR.">Evidence for in vitro falsely-primed cDNAs that prevent specific detection of virus negative strand RNAs in dengue-infected cells: improvement by tagged RT-PCR.</a> J Virol Methods. 113 (1), 19-28 (2003).</li><li>Boncristiani, H. F., Di Prisco, G., Pettis, J. S., Hamilton, M., Chen, Y. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+approaches+to+the+analysis+of+deformed+wing+virus+replication+and+pathogenesis+in+the+honey+bee,+Apis+mellifera.">Molecular approaches to the analysis of deformed wing virus replication and pathogenesis in the honey bee, Apis mellifera.</a> Virol J. 6, 221 (2009).</li><li>Boncristiani, H. F., Rossi, R. D., Criado, M. F., Furtado, F. M., Arruda, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+purification+of+biotinylated+cDNA+removes+false+priming+and+ensures+strand-specificity+of+RT-PCR+for+enteroviral+RNAs.">Magnetic purification of biotinylated cDNA removes false priming and ensures strand-specificity of RT-PCR for enteroviral RNAs.</a> J Virol Methods. 161 (1), 147-153 (2009).</li><li>Craggs, J. K., Ball, J. K., Thomson, B. J., Irving, W. L., Grabowska, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+strand-specific+RT-PCR+based+assay+to+detect+the+replicative+form+of+hepatitis+C+virus+RNA.">Development of a strand-specific RT-PCR based assay to detect the replicative form of hepatitis C virus RNA.</a> J Virol Methods. 94 (1-2), 111-120 (2001).</li><li>Barbeau, B., Mesnard, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Making+sense+out+of+antisense+transcription+in+human+T-cell+lymphotropic+viruses+(HTLVs).">Making sense out of antisense transcription in human T-cell lymphotropic viruses (HTLVs).</a> Viruses. 3 (5), 456-468 (2011).</li></ol>

In this report we describe a strand-specific RT assay applied to the detection of ASP RNA in CD4+ T cells isolated from individuals infected with HIV-1. The occurrence of non-specific priming during RT hampers the detection of RNA transcripts with the right polarity, leading to misinterpretation of the results. Previous groups have developed several strategies aimed at preventing primer-independent cDNA synthesis during the RT reaction. Tagging the reverse primer at the 3&#39; end with sequences not related to HIV has pr...

The antisense protein (ASP) gene is an open reading frame (ORF) located on the negative strand of the human immunodeficiency virus type 1 (HIV-1) envelope (env) gene, spanning the junction gp120/gp411. Over the past 30 years, several reports have shown that the HIV ASP gene is indeed transcribed and translated2,3,4,5,6,7,8,9. Although ASP antisense transcripts have been fully characterized in vitro, until recently information about the actual production of ASP RNA in patients was still missing.
The sequence of ASP is reverse and complementary to env. This represents a major obstacle when trying to detect transcripts for ASP. Standard reverse transcription-polymerase chain reaction (RT-PCR) methods use gene-specific antisense primers to synthesize complementary DNAs (cDNAs) of the right polarity. This approach, however, does not allow to determine the orientation (sense or antisense) of the initial RNA template, since RNA hairpins or loops can prime RT in both directions in absence of primers10, a phenomenon known as RT self-priming. Most ASP investigators sidestep the problem of RT self-priming using primers tagged with sequences that are not related to HIV-111,12. This strategy, however, does not eliminate the occurrence of the phenomenon, and may lead to potential carry-over of non-specific cDNAs into the PCR11.
We have recently developed a novel strand-specific RT-PCR assay for the study of antisense RNA and we have used it for ASP RNA detection in a cohort of six HIV-infected patients, as shown in Table 1. The procedure described below has been previously published by Antonio Mancarella et al.13. In our protocol, we avoid the production of non-specific cDNAs by a dual approach. Firstly, we eliminate RNA secondary structures by denaturing RNA at high temperature (94 &#176;C), and secondly, we reverse transcribe ASP RNA using a biotinylated ASP-specific primer and affinity-purify the resulting cDNA. By this approach, we are able to amplify only our target cDNA, since other non-specific RT products are either prevented from being generated (high temperature denaturation of RNA) or eliminated prior to PCR (affinity purification).

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>BD LSR II</td>
			<td>Becton Dickinson</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>BigDye Terminator v1.1 Cycle Sequencing Kit</td>
			<td>Applied Biosystem, Thermo Fisher Scientific</td>
			<td>4337450</td>
			<td></td>
		</tr>
		<tr>
			<td>dNTP Set (100 mM)</td>
			<td>Invitrogen, Thermo Fisher Scientific</td>
			<td>10297018</td>
			<td></td>
		</tr>
		<tr>
			<td>Dynabeads M-280 Streptavidin</td>
			<td>Invitrogen, Thermo Fisher Scientific</td>
			<td>11205D</td>
			<td></td>
		</tr>
		<tr>
			<td>EasySep Human CD4+ T Cell Isolation Kit</td>
			<td>Stemcell Technologies</td>
			<td>19052</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Biowest</td>
			<td>S1010-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Fixation/Permeabilization Solution Kit</td>
			<td>Becton Dickinson</td>
			<td>554714</td>
			<td></td>
		</tr>
		<tr>
			<td>HIV Gag p24 flow cytometry antibody - Kc57-FITC</td>
			<td>Beckman Coulter</td>
			<td>6604665</td>
			<td></td>
		</tr>
		<tr>
			<td>Human IL-2</td>
			<td>Miltenyi Biotec</td>
			<td>130-097-743</td>
			<td></td>
		</tr>
		<tr>
			<td>Lectin from Phaseolus vulgaris (PHA)</td>
			<td>Sigma-Aldrich</td>
			<td>61764-1MG</td>
			<td></td>
		</tr>
		<tr>
			<td>LIVE/DEAD Fixable Yellow Dead Cell Stain Kit, for 405 nm excitation</td>
			<td>Invitrogen, Thermo Fisher Scientific</td>
			<td>L34967</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Anti-Human CD28</td>
			<td>Becton Dickinson</td>
			<td>55725</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Anti-Human CD3</td>
			<td>Becton Dickinson</td>
			<td>55329</td>
			<td></td>
		</tr>
		<tr>
			<td>Primers and Probes</td>
			<td>Integrated DNA Technologies (IDT)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin</td>
			<td>BioConcept</td>
			<td>4-01F00-H</td>
			<td></td>
		</tr>
		<tr>
			<td>Platinum Taq DNA Polymerase High Fidelity</td>
			<td>Invitrogen, Thermo Fisher Scientific</td>
			<td>11304011</td>
			<td></td>
		</tr>
		<tr>
			<td>Polybrene Infection / Transfection Reagent</td>
			<td>Sigma-Aldrich</td>
			<td>TR-1003-G</td>
			<td></td>
		</tr>
		<tr>
			<td>RNeasy Mini Kit</td>
			<td>Qiagen</td>
			<td>74104</td>
			<td></td>
		</tr>
		<tr>
			<td>Roswell Park Memorial Institute (RPMI) 1640 Medium</td>
			<td>Gibco, Thermo Fisher Scientific</td>
			<td>11875093</td>
			<td></td>
		</tr>
		<tr>
			<td>StepOnePlus Real-Time PCR System</td>
			<td>Applied Biosystem, Thermo Fisher Scientific</td>
			<td>4376600</td>
			<td></td>
		</tr>
		<tr>
			<td>SuperScript III Reverse Transcriptase</td>
			<td>Invitrogen, Thermo Fisher Scientific</td>
			<td>18080044</td>
			<td></td>
		</tr>
		<tr>
			<td>TaqMan Gene Expression Master Mix</td>
			<td>Applied Biosystem, Thermo Fisher Scientific</td>
			<td>4369016</td>
			<td></td>
		</tr>
		<tr>
			<td>TOPO TA Cloning Kit for Subcloning, with One Shot TOP10 chemically competent E. coli cells</td>
			<td>Invitrogen, Thermo Fisher Scientific</td>
			<td>K450001</td>
			<td></td>
		</tr>
		<tr>
			<td>TURBO DNase (2 U/&#181;L)</td>
			<td>Invitrogen, Thermo Fisher Scientific</td>
			<td>AM2238</td>
			<td></td>
		</tr>
		<tr>
			<td>Veriti Thermal Cycler</td>
			<td>Applied Biosystem, Thermo Fisher Scientific</td>
			<td>4375786</td>
			<td></td>
		</tr>
	</tbody>
</table>

detection of human immunodeficiency virus type 1 (hiv-1) antisense protein (asp) rna transcripts in patients by strand-specific rt-pcr

In retroviruses, antisense transcription has been described in both human immunodeficiency virus type 1 (HIV-1) and human T-lymphotropic virus 1 (HTLV-1). In HIV-1, the antisense protein ASP gene is located on the negative strand of env, in the reading frame -2, spanning the junction gp120/gp41. In the sense orientation, the 3&#39; end of the ASP open reading frame overlaps with gp120 hypervariable regions V4 and V5. The study of ASP RNA has been thwarted by a phenomenon known as RT-self-priming, whereby RNA secondary structures have the ability to prime RT in absence of the specific primer, generating non-specific cDNAs. The combined use of high RNA denaturation with biotinylated reverse primers in the RT reaction, together with affinity purification of the cDNA onto streptavidin-coated magnetic beads, has allowed us to selectively amplify ASP RNA in CD4+ T cells derived from individuals infected with HIV-1. Our method is relatively low-cost, simple to perform, highly reliable, and easily reproducible. In this respect, it represents a powerful tool for the study of antisense transcription not only in HIV-1 but also in other biological systems.

High temperature RNA denaturation coupled to affinity purification of biotinylated cDNA prevents amplification of non-specific ASP products during PCR in PBMCs infected in vitro and in CD4+ T cells isolated from patients. RT self-priming has been shown to occur during reverse transcription of antisense RNAs10,14,15,16,17. In order to prevent this phen...

Watch this Scientific Journal Video about Detection of Human Immunodeficiency Virus Type 1 HIV-1 Antisense Protein ASP RNA Transcripts in Patients by Strand-Specific RT-PCR at JoVE.com

Detection of Human Immunodeficiency Virus Type 1 HIV-1 Antisense Protein ASP RNA Transcripts in Patients by Strand-Specific RT-PCR

RNA hairpins and loops can function as primers for reverse transcription (RT) in absence of sequence-specific primers, interfering with the study of overlapping antisense transcripts. We have developed a technique able to identify strand-specific RNA, and we have used it to study HIV-1 antisense protein ASP.

Detection of Human Immunodeficiency Virus Type 1 (HIV-1) Antisense Protein (ASP) RNA Transcripts in Patients by Strand-Specific RT-PCR

In retroviruses, antisense transcription has been described in both human immunodeficiency virus type 1 (HIV-1) and human T-lymphotropic virus 1 (HTLV-1). ...

Conventional RT-PCRs do not allow for discrimination between the sense and anti-sense sequences when used to detect RNAs encoded by overlapping genes. This protocol makes it possible to detect specifically anti-sense RNAs. The use of a biotynylated primers along with high RNA denaturation temperatures allows for amplification of anti-sense cDNAs, preventing the formation of non-specific RT products.We have used this method to demonstrate that ASP either as an RNA anti-sense or a protein precursor, it's a new HIV antigen, does it potentially a novel HIV target for therapy. This method can be applied to any system, in which anti-sense RNAs from overlapping genes can be detected. Start by designing patient specific primers using the pro-viral DNA sequence internal to the PanASP primers.Next, quantify the RNA and eliminate DNA contamination by treating samples with DNase. Transfer between 0.1 and one microgram of total RNA into the appropriate wells on a 96 well PCR plate. Then set up the reverse transcription, or RT reaction, according to manuscript directions.Prepare the endogenous RT controls by adding five microliters of nuclease free water instead of the ASP reverse primer. Put the plate into the thermocycler and heat the RNA to 94 degrees Celsius for five minutes. Then immediately cool it in iced water for at least one minute.Prepare the reaction mixture in a 1.5 milliliter tube as described in the text manuscript, then transfer 17.5 microliters to each of the RNA containing wells. RNA denaturation must be performed at 94 degrees Centigrade. Without total denaturation, syntheses of non-specific products from sense RNA may occur, leading to amplification of non-specific cDNAs.Mix the contents of the wells gently and incubate the plate at 55 degrees Celsius for 60 minutes. Then, inactivate the reactions by heating the plate to 70 degrees Celsius for 15 minutes. Prepare one liter of 2X washing and binding buffer according to manuscript directions and filter the solution.Next, prepare 50 milliliters of 1X washing and binding buffer using PCR grade water. Transfer the appropriate number of streptavidin-conjugated magnetic beads to a 1.5 milliliter tube then wash them by adding an equal volume of 2X washing and binding buffer and vortexing the tube for 15 seconds. Place the tube into a magnetic separation rack and incubate it for three minutes at room temperature.Then, carefully remove the supernatant without disturbing the beads and add the same volume of the 2X washing and binding buffer as the initial volume of the beads. Vortex the beads for 30 seconds and transfer 10 microliters of the suspension to an appropriate number of 1.5 milliliter tubes. Place the tubes in the magnetic separation rack and incubate them for three minutes at room temperature.Then, discard the supernatant and add 50 microliters of 2X washing and binding buffer. Add 50 microliters of biotynylated cDNA to the corresponding tubes with the beads and incubate them for 30 minutes while gently rotating. After the incubation, place the tubes on the magnetic separation rack for three minutes then wash the beads with 200 microliters of 1X washing and binding buffer, followed by a three minute incubation on the separation rack.Discard the supernatant and repeat the wash twice. Then, resuspend the beads in 10 microliters of PCR grade water. Prepare an appropriate volume of PCR Master Mix according to the manuscript directions.Mix it well and quickly spin it down, then transfer 49 microliters per well to a 96 well PCR plate. Carefully vortex the tubes with the purified cDNA for 15 seconds and add one microliter of the suspension to the corresponding wells. Run the PCR and separate the products on a 1%agarose gel.Cut the bands from the gel and clone the amplified products into a PCR 2.1 plasmid. Then sequence the clones and analyze each sequence. The initial RT reactions were performed with the regular non-biotynylated anti-sense primer and resulted in successful amplification of ASP.However, a band of the same molecular weight and primer minus controls was also amplified. To bypass this problem, the specific anti-sense primer was labeled with biotyn and the resulting anti-sense cDNA was purified prior to PCR. This made it possible to amplify the ASP sequence with greatly reduced contamination from the non-specific cDNA in the primer minus controls.Further optimization of this method was achieved by complete denaturation of RNA at 94 degrees Celsius prior to RT, followed by immediate cooling on ice water, which resulted in effective amplification of the ASP band and no non-specific products. The kinetics of ASP RNA were measured and CD4 cells isolated from three HIV positive subjects with detectable viremia and an absence of therapy following stimulation with anti-CD3/CD28. Quantification of ASP RNA was also possible in patients undergoing ART, with non-detectable viremia.In two out of three patients, ASP RNA was detected in low levels at three to five days post stimulation. Two patients were analyzed for ASP and env RNAs, one untreated and one treated. For the untreated patient, both RNAs could be detected.For the treated patient, ASP and env were barely detectable after several days of stimulation. When attempting this procedure, it is important to remember that denaturation linearizes RNA so that secondary structures able to prime RT are destroyed. Whereas, washing of the beads flushes away non-biotynylated cDNAs.After purification of the cDNAs with the correct polarity, qPCR can be performed to analyze gene expression. Moreover, cDNAs can also be cloned and used for sequence analysis. This method allows studying genes overlapping in opposite orientation and may be useful in elucidating regulation and pathogenesis of a bacteria and a virus-related diseases including some types of cancer.

detection-human-immunodeficiency-virus-type-1-hiv-1-antisense-protein

Research

JoVE Journal

Genetics

Analysis of Termination of Transcription Using BrUTP-strand-specific Transcription Run-on (TRO) Approach

This manuscript describes a protocol for detecting transcription termination defect in vivo. The strand-specific TRO protocol using BrUTP described here is a powerful experimental approach for analyzing the transcription termination defect under physiological conditions. Like the traditional TRO assay, it relies on the presence of a transcriptionally active polymerase beyond the 3&#8242; end of the gene as an indicator of a transcription termination defect1. It overcomes two major problems encountered with the traditional TRO assay. First, it can detect if the polymerase reading through the termination signal is the one that initiated transcription from the promoter-proximal region, or if it is simply representing a pervasively transcribing polymerase that initiated non-specifically from somewhere in the body or the 3&#8242; end of the gene. Secondly, it can distinguish if the transcriptionally active polymerase signal beyond the terminator region is truly the readthrough sense mRNA transcribing polymerase or a terminator-initiated non-coding anti-sense RNA signal. Briefly, the protocol involves permeabilizing the exponentially growing yeast cells, allowing the transcripts that initiated in vivo to elongate in the presence of the BrUTP nucleotide, purifying BrUTP-labelled RNA by the affinity approach, reverse transcribing the purified nascent RNA and amplifying the cDNA using strand-specific primers flanking the promoter and the terminator regions of the gene2.

Analysis of Termination of Transcription Using BrUTP-strand-specific Transcription Run-on TRO Approach

We describe a basic experimental approach for analysis of termination of transcription by RNA polymerase II in vivo using BrUTP by the strand-specific transcription run-on (TRO) approach in budding yeast. This protocol can be extended to study transcription termination by other RNA polymerases both in yeast and higher eukaryotes.

This manuscript describes a protocol for detecting transcription termination defect in vivo. The strand-specific TRO protocol using BrUTP described here ...

Semi-quantitative Detection of RNA-dependent RNA Polymerase Activity of Human Telomerase Reverse Transcriptase Protein

Human telomerase reverse transcriptase (TERT) is the catalytic subunit of telomerase, and it elongates telomere through RNA-dependent DNA polymerase activity. Although TERT is named as a reverse transcriptase, structural and phylogenetic analyses of TERT demonstrate that TERT is a member of right-handed polymerases, and relates to viral RNA-dependent RNA polymerases (RdRPs) as well as viral reverse transcriptase. We firstly identified RdRP activity of human TERT that generates complementary RNA stand to a template non-coding RNA and contributes to RNA silencing in cancer cells. To analyze this non-canonical enzymatic activity, we developed RdRP assay with recombinant TERT in 2009, thereafter established in vitro RdRP assay for endogenous TERT. In this manuscript, we describe the latter method. Briefly, TERT immune complexes are isolated from cells, and incubated with template RNA and rNTPs including radioactive rNTP for RdRP reaction. To eliminate single-stranded RNA, reaction products are treated with RNase I, and the final products are analyzed with polyacrylamide gel electrophoresis. Radiolabeled RdRP products can be detected by autoradiography after overnight exposure.

Human telomerase reverse transcriptase (TERT) synthesizes not only telomeric DNA but also double-stranded RNA through RNA-dependent RNA polymerase activity. Here, we describe a newly established assay to detect RNA-dependent RNA polymerase activity of endogenous TERT.

Human telomerase reverse transcriptase (TERT) is the catalytic subunit of telomerase, and it elongates telomere through RNA-dependent DNA polymerase ...

Adapting 3' Rapid Amplification of CDNA Ends to Map Transcripts in Cancer

Maturation of eukaryotic mRNAs involves 3&#39; end formation, which involves the addition of a poly(A) tail. In order to map the 3&#39; end of a gene, the traditional method of choice is 3&#39; rapid amplification of cDNA ends (3&#39; RACE). Protocols for 3&#39; RACE require the careful design and selection of nested primers within the 3&#39; untranslated region (3&#39; UTR) of the target gene of interest. However, with a few modifications the protocol can be used to include the entire 3&#39; UTR and sequences within the open reading frame (ORF), providing a more comprehensive picture of the relationship between the ORF and the 3&#39; UTR. This is in addition to identification of the polyadenylation signal (PAS), as well as the cleavage and polyadenylation site provided by conventional 3&#39; RACE. Expanded 3&#39; RACE can detect unusual 3&#39; UTRs, including gene fusions within the 3&#39; UTR, and the sequence information can be used to predict potential miRNA binding sites as well as AU rich destabilizing elements that may affect the stability of the transcript.

The two different 3&#39; rapid amplification of cDNA ends (3&#39; RACE) protocols described here make use of two different DNA polymerases to map sequences that include a segment of the open reading frame (ORF), the stop codon, and the entire 3&#39; UTR of a transcript using RNA obtained from different cancer cell lines.

Maturation of eukaryotic mRNAs involves 3&#39; end formation, which involves the addition of a poly(A) tail. In order to map the 3&#39; end of a gene, the ...

CRISPR-Mediated Reorganization of Chromatin Loop Structure

Recent studies have clearly shown that long-range, three-dimensional chromatin looping interactions play a significant role in the regulation of gene expression, but whether looping is responsible for or a result of alterations in gene expression is still unknown. Until recently, how chromatin looping affects the regulation of gene activity and cellular function has been relatively ambiguous, and limitations in existing methods to manipulate these structures prevented in-depth exploration of these interactions. To resolve this uncertainty, we engineered a method for selective and reversible chromatin loop re-organization using CRISPR-dCas9 (CLOuD9). The dynamism of the CLOuD9 system has been demonstrated by successful localization of CLOuD9 constructs to target genomic loci to modulate local chromatin conformation. Importantly, the ability to reverse the induced contact and restore the endogenous chromatin conformation has also been confirmed. Modulation of gene expression with this method establishes the capacity to regulate cellular gene expression and underscores the great potential for applications of this technology in creating stable de novo chromatin loops that markedly affect gene expression in the contexts of cancer and development.

Chromatin looping plays a significant role in gene regulation; however, there have been no technological advances that allow for selective and reversible modification of chromatin loops. Here we describe a powerful system for chromatin loop re-organization using CRISPR-dCas9 (CLOuD9), demonstrated to selectively and reversibly modulate gene expression at targeted loci.

Recent studies have clearly shown that long-range, three-dimensional chromatin looping interactions play a significant role in the regulation of gene ...

Rare Event Detection Using Error-corrected DNA and RNA Sequencing

Conventional next-generation sequencing techniques (NGS) have allowed for immense genomic characterization for over a decade. Specifically, NGS has been used to analyze the spectrum of clonal mutations in malignancy. Though far more efficient than traditional Sanger methods, NGS struggles with identifying rare clonal and subclonal mutations due to its high error rate of ~0.5&#8211;2.0%. Thus, standard NGS has a limit of detection for mutations that are &#62;0.02 variant allele fraction (VAF). While the clinical significance for mutations this rare in patients without known disease remains unclear, patients treated for leukemia have significantly improved outcomes when residual disease is &#60;0.0001 by flow cytometry. In order to mitigate this artefactual background of NGS, numerous methods have been developed. Here we describe a method for Error-corrected DNA and RNA Sequencing (ECS), which involves tagging individual molecules with both a 16 bp random index for error-correction and an 8 bp patient-specific index for multiplexing. Our method can detect and track clonal mutations at variant allele fractions (VAFs) two orders of magnitude lower than the detection limit of NGS and as rare as 0.0001 VAF.

Next-generation sequencing (NGS) is a powerful tool for genomic characterization that is limited by the high error rate of the platform (~0.5&#8211;2.0%). We describe our methods of error-corrected sequencing that allow us to obviate the NGS error rate and detect mutations at variant allele fractions as rare as 0.0001.

Conventional next-generation sequencing techniques (NGS) have allowed for immense genomic characterization for over a decade. Specifically, NGS has been ...

Amplification of Near Full-length HIV-1 Proviruses for Next-Generation Sequencing

The Full-Length Individual Proviral Sequencing (FLIPS) assay is an efficient and high-throughput method designed to amplify and sequence single, near full-length (intact and defective), HIV-1 proviruses. FLIPS allows determination of the genetic composition of integrated HIV-1 within a cell population. Through identifying defects within HIV-1 proviral sequences that arise during reverse transcription, such as large internal deletions, deleterious stop codons/hypermutation, frameshift mutations, and mutations/deletions in cis acting elements required for virion maturation, FLIPS can identify integrated proviruses incapable of replication. The FLIPS assay can be utilized to identify HIV-1 proviruses that lack these defects and are&#160;therefore potentially replication-competent. The FLIPS protocol involves: lysis of HIV-1 infected cells, nested PCR of near full-length HIV-1 proviruses (using primers targeted to the HIV-1 5&#39; and 3&#39; LTR), DNA purification and quantification, library preparation for Next-generation Sequencing (NGS), NGS, de novo assembly of proviral contigs, and a simple process of elimination for identifying replication-competent proviruses. FLIPS provides advantages over traditional methods designed to sequence integrated HIV-1 proviruses, such as single-proviral sequencing. FLIPS amplifies and sequences near full-length proviruses enabling replication competency to be determined, and also uses fewer amplification primers, preventing the consequences of primer mismatches. FLIPS is a useful tool for understanding the genetic landscape of integrated HIV-1 proviruses, especially within the latent reservoir, however, its utilization can extend to any application in which the genetic composition of integrated HIV-1 is required.

Full-length individual proviral sequencing (FLIPS) provides an efficient and high-throughput method for the amplification and sequencing of single, near full-length (intact and defective) HIV-1 proviruses and allows for determination of their potential replication-competency. FLIPS overcomes limitations of previous assays designed to sequence the latent HIV-1 reservoir.

The Full-Length Individual Proviral Sequencing (FLIPS) assay is an efficient and high-throughput method designed to amplify and sequence single, near ...

Determining 3'-Termini and Sequences of Nascent Single-Stranded Viral DNA Molecules during HIV-1 Reverse Transcription in Infected Cells

Monitoring of nucleic acid intermediates during virus replication provides insights into the effects and mechanisms of action of antiviral compounds and host cell proteins on viral DNA synthesis. Here we address the lack of a cell-based, high-coverage, and high-resolution assay that is capable of defining retroviral reverse transcription intermediates within the physiological context of virus infection. The described method captures the 3'-termini of nascent complementary DNA (cDNA) molecules within HIV-1 infected cells at single nucleotide resolution. The protocol involves harvesting of whole cell DNA, targeted enrichment of viral DNA via hybrid capture, adaptor ligation, size fractionation by gel purification, PCR amplification, deep sequencing, and data analysis. A key step is the efficient and unbiased ligation of adaptor molecules to open 3'-DNA termini. Application of the described method determines the abundance of reverse transcripts of each particular length in a given sample. It also provides information about the (internal) sequence variation in reverse transcripts and thereby any potential mutations. In general, the assay is suitable for any questions relating to DNA 3'-extension, provided that the template sequence is known.

Here we present a deep sequencing approach that provides an unbiased determination of nascent 3&#39;-termini as well as mutational profiles of single-stranded DNA molecules. The main application is the characterization of nascent retroviral complementary DNAs (cDNAs), the intermediates generated during the process of retroviral reverse transcription.

Monitoring of nucleic acid intermediates during virus replication provides insights into the effects and mechanisms of action of antiviral compounds and ...

An Assay for Quantifying Protein-RNA Binding in Bacteria

In the initiation step of protein translation, the ribosome binds to the initiation region of the mRNA. Translation initiation can be blocked by binding of an RNA binding protein (RBP) to the initiation region of the mRNA, which interferes with ribosome binding. In the presented method, we utilize this blocking phenomenon to quantify the binding affinity of RBPs to their cognate and non-cognate binding sites. To do this, we insert a test binding site in the initiation region of a reporter mRNA and induce the expression of the test RBP. In the case of RBP-RNA binding, we observed a sigmoidal repression of the reporter expression as a function of RBP concentration. In the case of no-affinity or very low affinity between binding site and RBP, no significant repression was observed. The method is carried out in live bacterial cells, and does not require expensive or sophisticated machinery. It is useful for quantifying and comparing between the binding affinities of different RBPs that are functional in bacteria to a set of designed binding sites. This method may be inappropriate for binding sites with high structural complexity. This is due to the possibility of repression of ribosomal initiation by complex mRNA structure in the absence of RBP, which would result in lower basal reporter gene expression, and thus less-observable reporter repression upon RBP binding.

In this method, we quantify the binding affinity of RNA binding proteins (RBPs) to cognate and non-cognate binding sites using a simple, live, reporter assay in bacterial cells. The assay is based on repression of a reporter gene.

In the initiation step of protein translation, the ribosome binds to the initiation region of the mRNA. Translation initiation can be blocked by binding ...

Identification of Footprints of RNA:Protein Complexes via RNA Immunoprecipitation in Tandem Followed by Sequencing (RIPiT-Seq)

RNA immunoprecipitation in tandem (RIPiT) is a method for enriching RNA footprints of a pair of proteins within an RNA:protein (RNP) complex. RIPiT employs two purification steps. First, immunoprecipitation of a tagged RNP subunit is followed by mild RNase digestion and subsequent non-denaturing affinity elution. A second immunoprecipitation of another RNP subunit allows for enrichment of a defined complex. Following a denaturing elution of RNAs and proteins, the RNA footprints are converted into high-throughput DNA sequencing libraries. Unlike the more popular ultraviolet (UV) crosslinking followed by immunoprecipitation (CLIP) approach to enrich RBP binding sites, RIPiT is UV-crosslinking independent. Hence RIPiT can be applied to numerous proteins present in the RNA interactome and beyond that are essential to RNA regulation but do not directly contact the RNA or UV-crosslink poorly to RNA. The two purification steps in RIPiT provide an additional advantage of identifying binding sites where a protein of interest acts in partnership with another cofactor. The double purification strategy also serves to enhance signal by limiting background. Here, we provide a step-wise procedure to perform RIPiT and to generate high-throughput sequencing libraries from isolated RNA footprints. We also outline RIPiT&#39;s advantages and applications and discuss some of its limitations.

Identification of Footprints of RNA:Protein Complexes via RNA Immunoprecipitation in Tandem Followed by Sequencing RIPiT-Seq

Here, we present a protocol to enrich endogenous RNA binding sites or &#34;footprints&#34;&#160;of RNA:protein (RNP) complexes from mammalian cells. This approach involves two immunoprecipitations of RNP subunits and is therefore dubbed RNA immunoprecipitation in tandem (RIPiT).

RNA immunoprecipitation in tandem (RIPiT) is a method for enriching RNA footprints of a pair of proteins within an RNA:protein (RNP) complex. RIPiT ...

Discrimintion and Mapping of the Primary and Processed Transcripts in Maize Mitochondrion Using a Circular RT-PCR-based Strategy

In plant mitochondria, some steady-state transcripts have 5&#39; triphosphate derived from transcription initiation (primary transcripts), while the others contain 5&#39; monophosphate generated post-transcriptionally (processed transcripts). To discriminate between the two types of transcripts, several strategies have been developed, and most of them depend on presence/absence of 5&#39; triphosphate. However, the triphosphate at primary 5&#39; termini is unstable, and it hinders a clear discrimination of the two types of transcripts. To systematically differentiate and map the primary and processed transcripts stably accumulated in maize mitochondrion, we have developed a circular RT-PCR (cRT-PCR)-based strategy by combining cRT-PCR, RNA 5&#39; polyphoshpatase treatment, quantitative RT-PCR (RT-qPCR), and Northern blot. As an improvement, this strategy includes an RNA normalization step to minimize the influence of unstable 5&#39; triphosphate.
In this protocol, the enriched mitochondrial RNA is pre-treated by RNA 5&#39; polyphosphatase, which converts 5&#39; triphsophate to monophosphate. After circularization and reverse transcription, the two cDNAs derived from 5&#39; polyphosphatase-treated and non-treated RNAs are normalized by maize 26S mature rRNA, which has a processed 5&#39; end and is insensitive to 5&#39; polyphosphatase. After normalization, the primary and processed transcripts are discriminated by comparing cRT-PCR and RT-qPCR products obtained from the treated and non-treated RNAs. The transcript termini are determined by cloning and sequencing of the cRT-PCR products, and then verified by Northern blot.
By using this strategy, most steady-state transcripts in maize mitochondrion have been determined. Due to the complicated transcript pattern of some mitochondrial genes, a few steady-state transcripts were not differentiated and/or mapped, though they were detected in a Northern blot. We are not sure whether this strategy is suitable to discriminate and map the steady-state transcripts in other plant mitochondria or in plastids.

We present a circular RT-PCR-based strategy by combining circular RT-PCR, quantitative RT-PCR, RNA 5&#39; polyphosphatase-treatment, and Northern blot. This protocol includes a normalization step to minimize the influence of unstable 5&#39; triphosphate, and it is suitable for discriminating and mapping the primary and processed transcripts stably accumulated in maize mitochondrion.

In plant mitochondria, some steady-state transcripts have 5&#39; triphosphate derived from transcription initiation (primary transcripts), while the ...