Funding was provided by the Deutsche Forschungsgemeinschaft (SPP1230, grant of the Tumor Center Heidelberg/Mannheim), by the Bundesministerium f&#252;r Bildung und Forschung (iGene), by the VIth + VIIth Framework Programs of the European Commission (CONSERT, CLINIGENE and PERSIST). We thank Ina Kutschera for demonstrating the protocol technique in the video.

1. Preparation of Linker Cassettes (LC)
<ol>
	<li>Mix 40 &#181;l of LC1 oligonucleotide (Table 1), 40 &#181;l of LC2 oligonucleotide (Table 1, with proper restriction enzyme overhang), 110 &#181;l Tris-HCl&#160;(100 mM, pH 7.5), and 10 &#181;l 250 mM MgCl2.</li>
	<li>Incubate at 95 &#176;C for 5min and let the reaction cool down slowly to room temperature. Add 300 &#181;l H2O and concentrate dsLinker-DNA on a centrifugation filter. Add 80 &#181;l H2O to the eluate and aliquot 10 &#181;l of prepared linker cassette in 0.2 PCR tubes.</li>
</ol>
2. Preamplification of Vector Genome Junctions
<ol>
	<li>For every sample to be analyzed prepare a 50 &#181;l PCR reaction.
	<ol>
		<li>Determine concentration of the DNA samples. Pipette x &#181;l (1-1,000 ng for LAM/100-1,000 ng for nrLAM) of DNA into a 0.2 ml PCR tube. Volume of DNA should be equal in each sample and in the range of 0.5 to 25 &#181;l.</li>
		<li>Prepare PCR master mix as described in Table 2. Mix (50 - x) &#181;l of the master mix with each DNA sample in 0.2 ml PCR tubes.</li>
	</ol>
	</li>
	<li>Preamplify vector genome junctions using PCR conditions exemplified in Table 2. After completion of PCR add 0.5 &#181;l Taq Polymerase to each PCR tube and rerun PCR program. PCR products can be stored at 4 &#176;C for up to 4 days or long term at -20 &#176;C.</li>
</ol>
3. Magnetic Separation of PCR Product
<ol>
	<li>Preparation of Magnetic Beads
	<ol>
		<li>Pipette 20 &#181;l (200 &#181;g) of streptavidin coated magnetic beads into a 1.5 ml tube and expose for 1 min on the magnetic particle separator (MPS) at room temperature. Discard supernatant.</li>
		<li>Remove tube from MPS and resuspend magnetic beads in 40 &#181;l PSB/ 0.1% BSA (pH 7.5). Expose to MPS for 1 min and discard supernatant. Repeat this step once.</li>
		<li>Wash beads with 20 &#181;l of 3 M LiCl solution (3 M LiCl, 10 mM Tris-HCl, 1 mM EDTA) expose to MPS for 1 min and discard supernatant. Resuspend beads in 50 &#181;l of 6 M LiCl solution (6 M LiCl, 10 mM Tris-HCl, 1 mM EDTA).</li>
	</ol>
	</li>
	<li>Mix entire PCR reaction from step 2.2 with 50 &#181;l of prepared magnetic beads. Incubate on a horizontal shaker (300 rpm) at least for 2 hr at room temperature. This step allows binding of biotinylated PCR product to streptavidin coated beads (DNA-Bead complex). DNA bead complex can be incubated on the shaker overnight or stored at 4 &#176;C for up to 4 days.</li>
	<li>Expose DNA-Bead complex to MPS for 1 min at room temperature, remove supernatant, and resuspend DNA-Bead complex in 100 &#181;l H2O. Immediately proceed with step 4 for LAM or step 5 for nrLAM.</li>
</ol>
4. LAM-Procedure
<ol>
	<li>Double Strand DNA (dsDNA) Synthesis (LAM only)
	<ol>
		<li>Expose DNA-Bead complex from step 3.3 to MPS for 1 min and discard supernatant. Add 8.25 &#181;l of H2O, 1 &#181;l 10x hexanucleotide buffer, 0.25 &#181;l dNTPs (10 mM) and 0.5 &#181;l (2 U) Klenow polymerase. Incubate at 37 &#176;C for 1 hr.</li>
		<li>Add 90 &#181;l of H2O and expose to MPS for 1 min. Discard supernatant and resuspend DNA-Bead complex in 100 &#181;l H2O.</li>
	</ol>
	</li>
	<li>Restriction Digest
	<ol>
		<li>Expose DNA-Bead complex to MPS for 1 min and discard supernatant. Add 8.5 &#181;l H2O, 1 &#181;l 10x restriction enzyme buffer and 0.5 &#181;l of restriction enzyme and incubate reaction for 1 hr. Repeat step 4.1.2. 
		NOTE: Incubate reaction at the temperature recommended by the manufacturer of the restriction enzyme. Make sure that there is no restriction site present within or downstream of the primer binding site used for preamplification in the DNA of interest. For choice of suitable restriction enzymes/restriction enzyme combinations refer to 9.</li>
	</ol>
	</li>
	<li>Ligation of ds Linker (LK)
	<ol>
		<li>Expose DNA-Bead complex to MPS for 1 min and discard supernatant. Add 5 &#181;l H2O, 1 &#181;l 10x FastLink buffer, 1 &#181;l ATP (10 mM), 2 &#181;l Linker cassette from step 1.2, and 1 &#181;l Fast-Link DNA Ligase (2 U/&#181;l). Incubate at room temperature for 5 min. Repeat step 4.1.2.</li>
	</ol>
	</li>
	<li>Denaturation of Synthesized dsDNA
	<ol>
		<li>Expose DNA-Bead complex to MPS for 1 min and discard supernatant. Resuspend DNA-Bead complex in 5 &#181;l 0.1 N NaOH. Incubate 5 min at room temperature on a horizontal shaker.</li>
		<li>Expose DNA-Bead complex to MPS for 1 min and collect preamplified vector-genome junction containing supernatant in new 1.5 ml tube. Immediately proceed with step 6 or store supernatant at -20 &#176;C.</li>
	</ol>
	</li>
</ol>
5. nrLAM-Procedure
<ol>
	<li>Ligation of single stranded linker (ssLC) (nrLAM only)
	<ol>
		<li>Expose DNA-Bead complex from step 3.3 to MPS for 1 min and discard supernatant. Add 6.5 &#181;l H2O, 1 &#181;l CircLigase 10x Reaction Buffer, 0.5 &#181;l MnCl2 (50 mM), 0.5 &#181;l ATP (1 mM), 1 &#181;l ssLinker oligonucleotide and 0.5 &#181;l CircLigase (100 U/&#181;l). Incubate at 60 &#176;C for 1 hr.</li>
		<li>Add 90 &#181;l of H2O and expose to MPS for 1 min. Discard supernatant and wash DNA-Bead complex in 100 &#181;l H2O. Again expose to MPS for 1 min, discard supernatant and resuspend DNA-Bead complex in 10 &#181;l H2O.</li>
	</ol>
	</li>
</ol>
6. Exponential Amplification I
<ol>
	<li>For every sample to be analyzed prepare a 50 &#181;l PCR reaction.
	<ol>
		<li>Pipette 2 &#181;l template DNA (from step 4.4.2 (LAM) or 5.1.2 (nrLAM)) into a 0.2 ml PCR tube.</li>
		<li>Prepare PCR master mix as described in Table 3. Add 48 &#181;l of master mix to each sample from step 6.1.1 and amplify vector genome junctions by PCR conditions exemplified in Table 3. PCR products can be stored at 4 &#176;C for up to 4 days or long term at -20 &#176;C.</li>
	</ol>
	</li>
</ol>
7. Magnetic Separation of PCR Product
<ol>
	<li>Prepare magnetic beads as exemplified in steps 3.1.1 - 3.1.3. Resuspend beads in 20 &#181;l (for LAM) or 50 &#181;l (for nrLAM) of 6 M LiCl solution (6 M LiCl, 10 mM Tris-HCl, 1 mM EDTA). Mix 20 &#181;l (LAM) or 50 &#181;l (nrLAM) of PCR reaction from step 6.1.2 with prepared magnetic beads (step 7.1) and incubate on a horizontal shaker (300 rpm) for 2 hr at room temperature. DNA bead complex can be incubated on the shaker overnight or stored at 4 &#176;C for up to 4 days.</li>
	<li>Expose DNA-Bead complex to MPS for 1 min, remove supernatant and resuspend DNA-Bead complex in 100 &#181;l H2O. Expose DNA-Bead complex to MPS for 1 min and discard supernatant.</li>
	<li>Resuspend DNA-Bead complex in 20 &#181;l (LAM) or 5 &#181;l (nrLAM) 0.1 N NaOH. Incubate for 10 min at room temperature on a horizontal shaker, expose to MPS for 1 min and collect amplified DNA containing supernatant in new 1.5 ml tube. Immediately proceed with step 8.1 or store supernatant at -20 &#176;C.</li>
</ol>
8. Exponential Amplification II
<ol>
	<li>For every sample to be analyzed prepare a 50 &#181;l PCR reaction.
	<ol>
		<li>Pipette 2 &#181;l template DNA (from step 7.3) into a 0.2 ml PCR tube.</li>
		<li>Prepare PCR master mix as described in Table 4. Add 48 &#181;l of master mix to each sample from step 8.1.1 and amplify vector genome junctions by PCR conditions exemplified in Table 4. PCR products can be stored at 4 &#176;C for up to 4 days or long term at -20 &#176;C.</li>
	</ol>
	</li>
	<li>To visualize (nr)LAM-PCR products, load 10 &#181;l of the PCR product from step 8.1.2 on a 2% agarose gel. If bands are visible, analyze 10 &#181;l of the LAM-PCR product on high-resolution gel. CAUTION: Ethidium bromide is mutagenic. Work very carefully and always wear appropriate gloves.</li>
</ol>
9. Preparation for High-throughput Sequencing
<ol>
	<li>Purification of (nr)LAM-PCR products
	<ol>
		<li>Mix 40 &#181;l PCR-Product from step 8.1.2 with 44 &#181;l of room temperature AMPure XP Magnetic Beads. Incubate 5 min at room temperature and expose to MPS for additional 2 min.</li>
		<li>Discard supernatant and wash twice with 200 &#181;l 70% EtOH on the MPS.</li>
		<li>Discard supernatant and resuspend DNA-Bead complex in 30 &#181;l H2O. Incubate 1 min and transfer supernatant to fresh 0.2 ml tube. Determine concentration of purified DNA.</li>
	</ol>
	</li>
	<li>Fusionprimer PCR to add sequencing specific adaptors.
	<ol>
		<li>For every sample to be analyzed prepare a 50 &#181;l PCR reaction.</li>
		<li>Pipette x &#181;l (40 ng) of DNA into a 0.2 ml PCR tube. Volume of DNA should be equal in each sample and in the range of 0.5 to 25 &#181;l.</li>
		<li>Prepare PCR master mix as described in table 5. Add (50 - x) &#181;l of master mix to each sample from step 9.2.2 and introduce Sequencing adaptors to (nr)LAM-PCR products by PCR conditions exemplified in Table 5. PCR products can be stored at 4 &#176;C for up to 4 days or long term at -20 &#176;C.</li>
		<li>To visualize Fusionprimer-PCR products load 10 &#181;l of the PCR product from step 9.2.3 on a 2% agarose gel. Purify remaining PCR product as described in steps 9.1.1 - 9.1.3. Analyze 1 &#181;l purified PCR product from step 9.4 on an automated high-resolution electrophoresis device to accurately quantify concentration and fragment size of Fusionprimer-PCR products.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Schmidt, 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=Detection+and+direct+genomic+sequencing+of+multiple+rare+unknown+flanking+DNA+in+highly+complex+samples.">Detection and direct genomic sequencing of multiple rare unknown flanking DNA in highly complex samples.</a> Hum Gene Ther. 12, 743-749 (2001).</li><li>Schmidt, 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=High-resolution+insertion-site+analysis+by+linear+amplification-mediated+PCR+(LAM-PCR).">High-resolution insertion-site analysis by linear amplification-mediated PCR (LAM-PCR).</a> Nat Methods. 4, 1051-1057 (2007).</li><li>Schroeder, A. R., 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+integration+in+the+human+genome+favors+active+genes+and+local+hotspots.">HIV-1 integration in the human genome favors active genes and local hotspots.</a> Cell. 110, 521-529 (2002).</li><li>Wu, X., Li, Y., Crise, B., Burgess, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcription+start+regions+in+the+human+genome+are+favored+targets+for+MLV+integration.">Transcription start regions in the human genome are favored targets for MLV integration.</a> Science. 300, 1749-1751 (2003).</li><li>Vigdal, T. J., Kaufman, C. D., Izsvak, Z., Voytas, D. F., Ivics, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Common+physical+properties+of+DNA+affecting+target+site+selection+of+sleeping+beauty+and+other+Tc1/mariner+transposable+elements.">Common physical properties of DNA affecting target site selection of sleeping beauty and other Tc1/mariner transposable elements.</a> J Mol Biol. 323, 441-452 (2002).</li><li>Lewinski, M. K., 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=Retroviral+DNA+integration:+viral+and+cellular+determinants+of+target-site+selection.">Retroviral DNA integration: viral and cellular determinants of target-site selection.</a> PLoS Pathog. 2, (2006).</li><li>Mueller, P. R., Wold, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+footprinting+of+a+muscle+specific+enhancer+by+ligation+mediated+PCR.">In vivo footprinting of a muscle specific enhancer by ligation mediated PCR.</a> Science. 246, 780-786 (1989).</li><li>Silver, J., Keerikatte, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+use+of+polymerase+chain+reaction+to+amplify+cellular+DNA+adjacent+to+an+integrated+provirus.">Novel use of polymerase chain reaction to amplify cellular DNA adjacent to an integrated provirus.</a> Journal of virology. 63, 1924-1928 (1989).</li><li>Gabriel, R., 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=Comprehensive+genomic+access+to+vector+integration+in+clinical+gene+therapy.">Comprehensive genomic access to vector integration in clinical gene therapy.</a> Nature medicine. 15, 1431-1436 (2009).</li><li>Harkey, M. 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=Multiarm+high-throughput+integration+site+detection:+limitations+of+LAM-PCR+technology+and+optimization+for+clonal+analysis.">Multiarm high-throughput integration site detection: limitations of LAM-PCR technology and optimization for clonal analysis.</a> Stem Cells Dev. 16, 381-392 (2007).</li><li>Wang, G. P., 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=DNA+bar+coding+and+pyrosequencing+to+analyze+adverse+events+in+therapeutic+gene+transfer.">DNA bar coding and pyrosequencing to analyze adverse events in therapeutic gene transfer.</a> Nucleic acids research. 36, (2008).</li><li>Paruzynski, 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=Genome-wide+high-throughput+integrome+analyses+by+nrLAM-PCR+and+next-generation+sequencing.">Genome-wide high-throughput integrome analyses by nrLAM-PCR and next-generation sequencing.</a> Nat. Protocols. 5, 1379-1395 (2010).</li><li>Hacein-Bey-Abina, 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=Insertional+oncogenesis+in+4+patients+after+retrovirus-mediated+gene+therapy+of+SCID-X1.">Insertional oncogenesis in 4 patients after retrovirus-mediated gene therapy of SCID-X1.</a> J Clin Invest. , 3132-3142 (2008).</li><li>Hacein-Bey-Abina, 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=LMO2-associated+clonal+T+cell+proliferation+in+two+patients+after+gene+therapy+for+SCID-X1.">LMO2-associated clonal T cell proliferation in two patients after gene therapy for SCID-X1.</a> Science. 302, 415-419 (2003).</li><li>Howe, S. J., 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=Insertional+mutagenesis+combined+with+acquired+somatic+mutations+causes+leukemogenesis+following+gene+therapy+of+SCID-X1+patients.">Insertional mutagenesis combined with acquired somatic mutations causes leukemogenesis following gene therapy of SCID-X1 patients.</a> J Clin Invest. 118, 3143-3150 (2008).</li><li>Cartier, N., 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=Hematopoietic+stem+cell+gene+therapy+with+a+lentiviral+vector+in+X-linked+adrenoleukodystrophy.">Hematopoietic stem cell gene therapy with a lentiviral vector in X-linked adrenoleukodystrophy.</a> Science. 326, 818-823 (2009).</li><li>Matrai, J., 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=Hepatocyte-targeted+expression+by+integrase-defective+lentiviral+vectors+induces+antigen-specific+tolerance+in+mice+with+low+genotoxic+risk.">Hepatocyte-targeted expression by integrase-defective lentiviral vectors induces antigen-specific tolerance in mice with low genotoxic risk.</a> Hepatology. 53, 1696-1707 (2011).</li><li>Penaud-Budloo, 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=Adeno-associated+virus+vector+genomes+persist+as+episomal+chromatin+in+primate+muscle.">Adeno-associated virus vector genomes persist as episomal chromatin in primate muscle.</a> Journal of virology. 82, 7875-7885 (2008).</li><li>Kaeppel, 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+largely+random+AAV+integration+profile+after+LPLD+gene+therapy.">A largely random AAV integration profile after LPLD gene therapy.</a> Nature medicine. 19, 889-891 (2013).</li><li>Voigt, K., 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=Retargeting+sleeping+beauty+transposon+insertions+by+engineered+zinc+finger+DNA-binding+domains.">Retargeting sleeping beauty transposon insertions by engineered zinc finger DNA-binding domains.</a> Mol Ther. 20, 1852-1862 (2012).</li><li>Yanez-Munoz, R. J., 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=Effective+gene+therapy+with+nonintegrating+lentiviral+vectors.">Effective gene therapy with nonintegrating lentiviral vectors.</a> Nature medicine. 12, 348-353 (2006).</li><li>Boztug, K., 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=Stem-Cell+Gene+Therapy+for+the+Wiskott-Aldrich+Syndrome.">Stem-Cell Gene Therapy for the Wiskott-Aldrich Syndrome.</a> N Engl J Med. 363, 1918-1927 (2010).</li><li>Deichmann, 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=Vector+integration+is+nonrandom+and+clustered+and+influences+the+fate+of+lymphopoiesis+in+SCID-X1+gene+therapy.">Vector integration is nonrandom and clustered and influences the fate of lymphopoiesis in SCID-X1 gene therapy.</a> J Clin Invest. 117, 2225-2232 (2007).</li><li>Schwarzwaelder, K., 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=Gammaretrovirus-mediated+correction+of+SCID-X1+is+associated+with+skewed+vector+integration+site+distribution+in+vivo.">Gammaretrovirus-mediated correction of SCID-X1 is associated with skewed vector integration site distribution in vivo.</a> J Clin Invest. 117, 2241-2249 (2007).</li><li>Gabriel, R., 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=An+unbiased+genome-wide+analysis+of+zinc-finger+nuclease+specificity.">An unbiased genome-wide analysis of zinc-finger nuclease specificity.</a> Nat Biotechnol. 29, 816-823 (2011).</li><li>Dieter, S. 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=Distinct+types+of+tumor-initiating+cells+form+human+colon+cancer+tumors+and+metastases.">Distinct types of tumor-initiating cells form human colon cancer tumors and metastases.</a> Cell Stem Cell. 9, 357-365 (2011).</li><li>Montini, 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=Hematopoietic+stem+cell+gene+transfer+in+a+tumor-prone+mouse+model+uncovers+low+genotoxicity+of+lentiviral+vector+integration.">Hematopoietic stem cell gene transfer in a tumor-prone mouse model uncovers low genotoxicity of lentiviral vector integration.</a> Nature biotechnology. 24, 687-696 (2006).</li><li>Zavidij, O., 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=Stable+long-term+blood+formation+by+stem+cells+in+murine+steady-state+hematopoiesis.">Stable long-term blood formation by stem cells in murine steady-state hematopoiesis.</a> Stem Cells. 30, 1961-1970 (2012).</li><li>Martins, V. 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=Thymus-autonomous+T+cell+development+in+the+absence+of+progenitor+import.">Thymus-autonomous T cell development in the absence of progenitor import.</a> J Exp Med. 209, 1409-1417 (2012).</li><li>Arens, 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=Bioinformatic+clonality+analysis+of+next-generation+sequencing-derived+viral+vector+integration+sites.">Bioinformatic clonality analysis of next-generation sequencing-derived viral vector integration sites.</a> Hum Gene Ther Methods. 23, 111-118 (2012).</li></ol>

The authors have nothing to disclose.

The LAM-PCR technique allows identifying unknown DNA sequences that flank a known DNA region. Because of the high sensitivity resulting from preamplification of the junctions with specific primers hybridizing in the known DNA sequence, it is possible to amplify and detect even rare junctions down to the single cell level. Contrary, in a polyclonal situation LAM-PCR is able to amplify thousands of different junctions in one single reaction.
However, due to the use of restriction enzymes only a ...

Linear-amplification mediated PCR (LAM-PCR) allows identifying and characterizing unknown flanking DNA adjacent to known DNA of any origin. More specifically, LAM-PCR has been developed to localize viral vector integration sites (IS) within the host genome1,2. Genetic elements like retroviruses or transposons integrate their genome into the host genome in a (semi-) random manner3-6. In many cases it is decisive to know exactly the position where these vectors integrated. LAM-PCR has been proven to be superior to alternative techniques like ligation-mediated PCR7 and its variants or inverse PCR8. The sensitivity and robustness of this method arises from the initial preamplification of the vector-genome junctions and magnetic selection of amplified PCR products. Like the alternative methods mentioned, LAM-PCR relies on the use of restriction enzymes, introducing a bias into retrieval capacity of IS9-11. Thus, only a subset of the IS repertoire (the integrome) can be detected in one reaction. This bias is minimized by the parallel analysis of a given sample using optimal combinations of restriction enzymes9. Recently, a variant of the technology termed non-restrictive LAM-PCR (nrLAM-PCR) has been developed that circumvents the use of restriction enzymes and allows unbiased genome-wide analysis of a sample in a single reaction9,12.
In the past, LAM-PCR has been used to identify the causative retroviral IS giving rise to leukemia in a few patients in clinical gene therapy trials13-15. Since then, LAM-PCR has been adapted to identify IS from other integrating vectors (lentiviral vectors, transposons) and also to identify integration patterns of passively integrating vectors like adeno-associated vectors (AAV) or integrase-defective lentiviral vectors (IDLV)16-21. Applications of LAM-PCR are wide spread: traditionally, the technique is widely used to study the clonal composition of gene modified cells in patients that have undergone gene therapy or to assess the biosafety of novel vector systems by unraveling their integration behavior15,16,22-24. Recently, LAM-PCR enabled determining specificity and off-target activity of designer nucleases by an IDLV trapping assay25.
Moreover, LAM-PCR allows to easily follow the fate of a transduced cell over time in an organism. This allows to identify proto-oncogenes as well as tumor suppressor genes and also to study hematopoiesis or cancer stem cell biology26-28. Last but not least, LAM-PCR was adapted to study T-cell receptor diversity in humans29 (and unpublished data).
The intrinsic power of the technology is reinforced by linking the method to deep sequencing technologies that allow characterizing millions of unknown flanking DNA with single nucleotide resolution in whole genomes. In the following protocol, we describe step-by step the amplification and identification of flanking unknown DNA exemplarily to identify lentiviral vector IS. Oligonucleotides used in the protocol are listed in Table 1. Extracted DNA or cDNA of any source can be used as DNA template for LAM-PCR and nrLAM-PCR.

<table border="0" cellpadding="0" cellspacing="0" width="1209">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Name of Material/ Equipment</td>
			<td style="width:203px;">Company</td>
			<td style="width:120px;">Catalog Number</td>
			<td style="width:527px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Taq DNA Polymerase</td>
			<td style="width:203px;">Genaxxon Bioscience GmbH</td>
			<td style="width:120px;">M3001.5000</td>
			<td>Alternative Taq Polymerases may be used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">PCR Buffer</td>
			<td style="width:203px;">Qiagen</td>
			<td style="width:120px;">201203</td>
			<td>Use of this buffer is recommended</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">dNTP-Mixture</td>
			<td style="width:203px;">Genaxxon Bioscience GmbH</td>
			<td style="width:120px;">M3015.4020</td>
			<td>or any other dNTPs</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Oligonucleotides (Primers)</td>
			<td style="width:203px;">MWG Biotech</td>
			<td style="width:120px;"></td>
			<td>HPLC purified</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Dynabeads M-280 Streptavidin&#160;</td>
			<td style="width:203px;">Invitrogen</td>
			<td style="width:120px;">11206D</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">PBS</td>
			<td style="width:203px;">Gibco</td>
			<td style="width:120px;">14190-086</td>
			<td>0.1 % wt/vol BSA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">6M LiCl</td>
			<td style="width:203px;">Roth</td>
			<td style="width:120px;">3739.1</td>
			<td>10 mM Tris-HCl&#160; (pH 7.5)/1 mM EDTA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Tris-HCl, pH 7.5</td>
			<td style="width:203px;">USB Corporation&#160;</td>
			<td style="width:120px;">22637</td>
			<td>or any other supplier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">EDTA</td>
			<td style="width:203px;">Applichem</td>
			<td style="width:120px;">A1103,0250</td>
			<td>or any other supplier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Klenow Polymerase</td>
			<td style="width:203px;">Roche Diagnostics</td>
			<td style="width:120px;">10104523001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Hexanucleotide mixture</td>
			<td style="width:203px;">Roche Diagnostics</td>
			<td style="width:120px;">11277081001</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Restriction endonuclease</td>
			<td style="width:203px;">NEB</td>
			<td style="width:120px;"></td>
			<td>or any other supplier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Fast-Link DNA ligation kit</td>
			<td style="width:203px;">Epicentre Biotechnologies</td>
			<td style="width:120px;">LK11025</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">CircLigase ssDNA Ligase Kit</td>
			<td style="width:203px;">Epicentre Biotechnologies</td>
			<td style="width:120px;">CL4111K</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">NaOH</td>
			<td style="width:203px;">Sigma-Aldrich</td>
			<td style="width:120px;">72068</td>
			<td>or any other supplier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Agarose LE</td>
			<td style="width:203px;">Roche Diagnostics</td>
			<td style="width:120px;">11685660001</td>
			<td>or any other supplier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">TBE buffer</td>
			<td style="width:203px;">Amresco</td>
			<td style="width:120px;">0658</td>
			<td>or any other supplier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Ethidium bromide</td>
			<td style="width:203px;">Applichem</td>
			<td style="width:120px;">A2273,0005</td>
			<td>Ethidium bromide is mutagenic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">100 bp DNA Ladder</td>
			<td style="width:203px;">Invitrogen</td>
			<td style="width:120px;">15628-050</td>
			<td>or any other DNA ladder</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">20 mM NaCl</td>
			<td style="width:203px;">Sigma-Aldrich</td>
			<td style="width:120px;">71393-1L</td>
			<td>or any other supplier</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Magna-Sep Magnetic Particle Separator&#160;</td>
			<td style="width:203px;">Life Technologies</td>
			<td style="width:120px;">K158501</td>
			<td>for use with 1.5 ml Tubes</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Magna-Sep Magnetic Particle Separator&#160;</td>
			<td style="width:203px;">Life Technologies</td>
			<td style="width:120px;">K158696</td>
			<td>for use with 96 well plates</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Amicon Ultra-0.5, Ultracel-30 membrane</td>
			<td style="width:203px;">Millipore</td>
			<td>UFC503096</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">PerfectBlue Gelsystem Midi S</td>
			<td style="width:203px;">PeqLab</td>
			<td style="width:120px;">40-1515</td>
			<td>or other electrophoresis system&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">TProfessional 96</td>
			<td style="width:203px;">Biometra</td>
			<td style="width:120px;">050-551</td>
			<td>or other Thermocycler for 96-well plates</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Orbital shaker KS 260 basic</td>
			<td style="width:203px;">IKA</td>
			<td style="width:120px;">2980200</td>
			<td>or other horizontal shaker</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">PCR softtubes 0.2 ml</td>
			<td style="width:203px;">Biozym Scientific GmbH</td>
			<td style="width:120px;">711082</td>
			<td>or other 0.2 ml PCR tubes</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">1.5 ml tubes</td>
			<td style="width:203px;">Eppendorf</td>
			<td style="width:120px;">12682</td>
			<td>or other 1.5 ml tubes</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Gel documentation system</td>
			<td style="width:203px;">PeqLab</td>
			<td style="width:120px;"></td>
			<td>or any other gel documentation system</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Nanodrop ND-1000 spectrophotometer</td>
			<td style="width:203px;">Thermo Scientific</td>
			<td style="width:120px;">ND-1000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">Spreadex EL1200 precast gel</td>
			<td style="width:203px;">Elchrom Scientific</td>
			<td style="width:120px;">3497</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:360px;">Submerged gel electrophoresis apparatus SEA 2000&#160;</td>
			<td style="width:203px;">Elchrom Scientific</td>
			<td style="width:120px;">2001E</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:360px;">2100 Electrophoresis Bioanalyzer</td>
			<td style="width:203px;">Agilent Technologies</td>
			<td>G2939AA</td>
			<td></td>
		</tr>
	</tbody>
</table>

linear amplification mediated pcr &#8211; localization of genetic elements and characterization of unknown flanking dna

Linear-amplification mediated PCR (LAM-PCR) has been developed to study hematopoiesis in gene corrected cells of patients treated by gene therapy with integrating vector systems. Due to the stable integration of retroviral vectors, integration sites can be used to study the clonal fate of individual cells and their progeny. LAM- PCR for the first time provided evidence that leukemia in gene therapy treated patients originated from provirus induced overexpression of a neighboring proto-oncogene. The high sensitivity and specificity of LAM-PCR compared to existing methods like inverse PCR and ligation mediated (LM)-PCR is achieved by an initial preamplification step (linear PCR of 100 cycles) using biotinylated vector specific primers which allow subsequent reaction steps to be carried out on solid phase (magnetic beads). LAM-PCR is currently the most sensitive method available to identify&#160;unknown DNA which is located in the proximity of known DNA. Recently, a variant of LAM-PCR has been developed that circumvents restriction digest thus abrogating retrieval bias of integration sites and enables a comprehensive analysis of provirus locations in host genomes. The following protocol explains step-by-step the amplification of both 3&#8217;- and 5&#8217;- sequences adjacent to the integrated lentiviral vector.

LAM-PCR results in amplification of vector genome junctions with a defined fragment size for each junction. The size of individual PCR fragments depends on the distance between the location of the known DNA in the genome and the closest restriction enzyme recognition site. This allows visualizing the diversity of amplified junctions in analyzed samples by gel electrophoresis, e.g., if only single (monoclonal), several (oligoclonal), or multiple (polyclonal) bands are present on the gel. The results of LAM-PCR ar...

Watch this Scientific Journal Video about Linear Amplification Mediated PCR â€“ Localization of Genetic Elements and Characterization of Unknown Flanking DNA at JoVE.com

Linear Amplification Mediated PCR &amp;#8211; Localization of Genetic Elements and Characterization of Unknown Flanking DNA

Linear-amplification mediated (LAM)-PCR is a method developed to identify the exact positions of integrating viral vectors in the genome. The technique has evolved to be the superior method to study clonal dynamics in gene therapy patients, biosafety of novel vector technologies, T-cell diversity, cancer stem cell models, etc.

Linear Amplification Mediated PCR &#8211; Localization of Genetic Elements and Characterization of Unknown Flanking DNA

Linear-amplification mediated PCR (LAM-PCR) has been developed to study hematopoiesis in gene corrected cells of patients treated by gene therapy with ...

linear-amplification-mediated-pcr-localization-genetic-elements

Research

JoVE Journal

Biology

30.0K Views.  National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ). Linear-amplification mediated (LAM)-PCR is a method developed to identify the exact positions of integrating viral vectors in the genome. The technique has evolved to be the superior method to study clonal dynamics in gene therapy patients, biosafety of novel vector technologies, T-cell diversity, cancer stem cell models, etc.

Video: Linear Amplification Mediated PCR &#8211; Localization of Genetic Elements and Characterization of Unknown Flanking DNA

Method for Culture of Early Chick Embryos ex vivo (New Culture)

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying  the formation and patterning of brain, neural tube, somite and heart primordia. Applications of chick embryo culture include electroporation of DNA or RNA constructs in order to analyze gene function, grafts of growth factor coated beads such as FGFs and BMPs , as well as whole mount in situ hybridization and immunohistochemistry. This video demonstrates the different steps in chick embryo culture; First, the embryo is explanted in saline. Then, the embryo is centered on a glass ring. The membranes surrounding the embryo are lifted along the walls of the ring. The ring is then placed in a culture dish containing a pool of albumine. The culture dish is sealed and placed in a humid chamber, where the embryo is cultured for up to 24 hrs. Finally, the embryo is removed from the ring, fixed and processed for further applications. A troubleshooting guide is also presented.

Method for Culture of Early Chick Embryos ex vivo New Culture

This video demonstrates New culture, a method by which chick embryos are cultured outside the egg for up to 24 hr. This method enables one to study early development (primitive streak to 14 som.), a period corresponding to E7-9 in mouse. Applications of this technique include electroporation, in situ hybridization and immunohistochemistry.

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ...

Double Whole Mount in situ Hybridization of Early Chick Embryos

The chick embryo is a valuable tool in the study of early embryonic development. Its transparency, accessibility and ease of manipulation, make it an ideal tool for studying  gene expression in brain, neural tube, somite and heart primordia formation. This video demonstrates the different steps in 2-color whole mount in situ hybridization; First, the embryo is dissected from the egg and fixed in paraformaldehyde. Second, the embryo is processed for prehybridization. The embryo is then hybridized with two different probes, one coupled to DIG, and one coupled to FITC.  Following overnight hybridization, the embryo is incubated with DIG coupled antibody. Color reaction for DIG substrate is performed, and the region of interest appears blue. The embryo is then incubated with FITC coupled antibody. The embryo is processed for color reaction with FITC, and the region of interest appears red. Finally, the embryo is fixed and processed for phtograph and sectioning. A troubleshooting guide is also presented.

This video demonstrates 2-color whole mount in situ hybridization, a method by which the spatial and temporal expression pattern of 2 different genes can be visualized in young chick embryos. This method was originally introduced by David Wilkinson, Domingos Henrique, Phil Ingham and David Ish -Horowicz.

Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System 

Understanding the roles of human DNA repair proteins in genetic pathways is a formidable challenge to many researchers. Genetic studies in mammalian systems have been limited due to the lack of readily available tools including defined mutant genetic cell lines, regulatory expression systems, and appropriate selectable markers. To circumvent these difficulties, model genetic systems in lower eukaryotes have become an attractive choice for the study of functionally conserved DNA repair proteins and pathways. We have developed a model yeast system to study the poorly defined genetic functions of the Werner syndrome helicase-nuclease (WRN) in nucleic acid metabolism. Cellular phenotypes associated with defined genetic mutant backgrounds can be investigated to clarify the cellular and molecular functions of WRN through its catalytic activities and protein interactions. The human WRN gene and associated variants, cloned into DNA plasmids for expression in yeast, can be placed under the control of a regulatory plasmid element. The expression construct can then be transformed into the appropriate yeast mutant background, and genetic function assayed by a variety of methodologies. Using this approach, we determined that WRN, like its related RecQ family members BLM and Sgs1, operates in a Top3-dependent pathway that is likely to be important for genomic stability. This is described in our recent publication [1] at <a href="http://www.impactaging.com">www.impactaging.com</a>. Detailed methods of specific assays for genetic complementation studies in yeast are provided in this paper.

Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System

Genetic studies in yeast can be employed to investigate the molecular and cellular functions of human genes in cellular DNA metabolism. Methods are described for the genetic characterization of the human WRN gene product defective in the premature aging disorder Werner syndrome in functionally conserved pathways using yeast as a tractable model system.

Understanding the roles of human DNA repair proteins in genetic pathways is a formidable challenge to many researchers.  Genetic studies in mammalian ...

Combining Single-molecule Manipulation and Imaging for the Study of Protein-DNA Interactions

The paper describes the combination of optical tweezers and single molecule fluorescence detection for the study of protein-DNA interaction. The method offers the opportunity of investigating interactions occurring in solution (thus avoiding problems due to closeby surfaces as in other single molecule methods), controlling the DNA extension and tracking interaction dynamics as a function of both mechanical parameters and DNA sequence. The methods for establishing successful optical trapping and nanometer localization of single molecules are illustrated. We illustrate the experimental conditions allowing the study of interaction of lactose repressor (lacI), labeled with Atto532, with a DNA molecule containing specific target sequences (operators) for LacI binding. The method allows the observation of specific interactions at the operators, as well as one-dimensional diffusion of the protein during the process of target search. The method is broadly applicable to the study of protein-DNA interactions but also to molecular motors, where control of the tension applied to the partner track polymer (for example actin or microtubules) is desirable.

Here we describe the instrumentation and methods for detecting single fluorescently-labeled protein molecules interacting with a single DNA molecule suspended between two optically trapped microspheres.

The paper describes the combination of optical tweezers and single molecule fluorescence detection for the study of protein-DNA interaction. The method ...

DNA Electroporation, Isolation and Imaging of Myofibers

Mature muscle has a unique structure that is amenable to live cell imaging. Herein, we describe the experimental protocol for expressing fluorescently labeled proteins in the flexor digitorum brevis (FDB) muscle. Conditions have been optimized to provide a large number of high quality myofibers expressing the electroporated plasmid while minimizing muscle damage. The method employs fluorescent tags on various proteins. Combining this expression method with high resolution confocal microscopy permits live cell imaging, including imaging after laser-induced damage. Fluorescent dyes combined with imaging of fluorescently-tagged proteins provides information regarding the basic structure of muscle and its response to stimuli.

This protocol utilizes electroporation to introduce and express fluorescently labeled proteins in mouse muscle fibers. Following recovery after electroporation, fibers are isolated. Individual fibers are then imaged using high resolution confocal microscopy to visualize muscle structure.

Mature muscle has a unique structure that is amenable to live cell imaging. Herein, we describe the experimental protocol for expressing fluorescently ...

In Vivo Alkaline Comet Assay and Enzyme-modified Alkaline Comet Assay for Measuring DNA Strand Breaks and Oxidative DNA Damage in Rat Liver

Unrepaired DNA damage can lead to genetic instability, which in turn may enhance cancer development. Therefore, identifying potential DNA damaging agents is important for protecting public health. The in vivo alkaline comet assay, which detects DNA damage as strand breaks, is especially relevant for assessing the genotoxic hazards of xenobiotics, as its responses reflect the in vivo absorption, tissue distribution, metabolism and excretion (ADME) of chemicals, as well as DNA repair process. Compared to other in vivo DNA damage assays, the assay is rapid, sensitive, visual and inexpensive, and, by converting oxidative DNA damage into strand breaks using specific repair enzymes, the assay can measure oxidative DNA damage in an efficient and relatively artifact-free manner. Measurement of DNA damage with the comet assay can be performed using both acute and subchronic toxicology study designs, and by integrating the comet assay with other toxicological assessments, the assay addresses animal welfare requirements by making maximum use of animal resources. Another major advantage of the assays is that they only require a small amount of cells, and the cells do not have to be derived from proliferating cell populations. The assays also can be performed with a variety of human samples obtained from clinically or occupationally exposed individuals.

In Vivo Alkaline Comet Assay and Enzyme-modified Alkaline Comet Assay for Measuring DNA Strand Breaks and Oxidative DNA Damage in Rat Liver

The alkaline comet assay measures DNA strand breaks in eukaryotic cells. By adding an Endonuclease III or human 8-oxoguanine-DNA-N-glycosylase digestion step, the assay can efficiently detect oxidative DNA damage. We describe methods for using these assays to detect DNA damage in rat liver.

Unrepaired DNA damage can lead to genetic instability, which in turn may enhance cancer development. Therefore, identifying potential DNA damaging agents ...

Amplification, Next-generation Sequencing, and Genomic DNA Mapping of Retroviral Integration Sites

Retroviruses exhibit signature integration preferences on both the local and global scales. Here, we present a detailed protocol for (1) generation of diverse libraries of retroviral integration sites using ligation-mediated PCR (LM-PCR) amplification and next-generation sequencing (NGS), (2) mapping the genomic location of each virus-host junction using BEDTools, and (3) analyzing the data for statistical relevance. Genomic DNA extracted from infected cells is fragmented by digestion with restriction enzymes or by sonication. After suitable DNA end-repair, double-stranded linkers are ligated onto the DNA ends, and semi-nested PCR is conducted using primers complementary to both the long terminal repeat (LTR) end of the virus and the ligated linker DNA. The PCR primers carry sequences required for DNA clustering during NGS, negating the requirement for separate adapter ligation. Quality control (QC) is conducted to assess DNA fragment size distribution and adapter DNA incorporation prior to NGS. Sequence output files are filtered for LTR-containing reads, and the sequences defining the LTR and the linker are cropped away. Trimmed host cell sequences are mapped to a reference genome using BLAT and are filtered for minimally 97% identity to a unique point in the reference genome. Unique integration sites are scrutinized for adjacent nucleotide (nt) sequence and distribution relative to various genomic features. Using this protocol, integration site libraries of high complexity can be constructed from genomic DNA in three days. The entire protocol that encompasses exogenous viral infection of susceptible tissue culture cells to integration site analysis can therefore be conducted in approximately one to two weeks. Recent applications of this technology pertain to longitudinal analysis of integration sites from HIV-infected patients.

We describe a protocol for amplifying retroviral integration sites from the genomic DNA of infected cells, sequencing the amplified virus-host junctions, and then mapping these sequences to a reference genome. We also describe techniques to quantify the distribution of integration sites relative to various genomic annotations using BEDTools.

Retroviruses exhibit signature integration preferences on both the local and global scales. Here, we present a detailed protocol for (1) generation of ...

High-throughput CRISPR Vector Construction and Characterization of DNA Modifications by Generation of Tomato Hairy Roots

Targeted DNA mutations generated by vectors with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 technology have proven useful for functional genomics studies. While most cloning strategies are simple to perform, they generally use multiple steps and can require several days to generate the ultimate constructs. The method presented here is based on DNA assembly and can produce fully functional CRISPR vectors in a single cloning reaction. Vector construction can also be pooled, further increasing the efficiency and utility of the process. A modification of the method is used to create CRISPR vectors with multiple gene targets. CRISPR vectors are then transformed into tomato hairy roots to generate transgenic materials with targeted DNA modifications. Hairy roots are a useful system for testing vector functionality as they are technically simple to generate and amenable to large-scale production. The methods presented here will have wide application as they can be used to generate a variety of CRISPR vectors and be used in a wide range of plant species.

Using DNA assembly, multiple CRISPR vectors can be constructed in parallel in a single cloning reaction, making the construction of large numbers of CRISPR vectors a simple task. Tomato hairy roots are an excellent model system to validate CRISPR vectors and generate mutant materials.

Targeted DNA mutations generated by vectors with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 technology have proven useful for ...

Characterization of MLKL-mediated Plasma Membrane Rupture in Necroptosis

Necroptosis is a programmed cell death pathway triggered by activation of receptor interacting protein kinase 3 (RIPK3), which phosphorylates and activates the mixed lineage kinase-like domain pseudokinase, MLKL, to rupture or permeabilize the plasma membrane. Necroptosis is an inflammatory pathway associated with multiple pathologies including autoimmunity, infectious and cardiovascular diseases, stroke, neurodegeneration, and cancer. Here, we describe protocols that can be used to characterize MLKL as the executioner of plasma membrane rupture in necroptosis. We visualize the process of necroptosis in cells using live-cell imaging with conventional and confocal fluorescence&#160;microscopy, and in fixed cells using electron microscopy, which together revealed the redistribution of MLKL from the cytosol to the plasma membrane prior to induction of large holes in the plasma membrane. We present in vitro nuclear magnetic resonance (NMR) analysis using lipids to identify putative modulators of MLKL-mediated necroptosis. Based on this method, we identified quantitative lipid-binding preferences and phosphatidyl-inositol phosphates (PIPs) as critical binders of MLKL that are required for plasma membrane targeting and permeabilization in necroptosis.

We report methods for characterization of MLKL-mediated plasma membrane rupture in necroptosis including conventional and confocal live-cell microscopy imaging, scanning electron microscopy, and NMR-based lipid binding.

Necroptosis is a programmed cell death pathway triggered by activation of receptor interacting protein kinase 3 (RIPK3), which phosphorylates and ...

Loop-Mediated Isothermal Amplification for Screening Salmonella in Animal Food and Confirming Salmonella from Culture Isolation

Loop-mediated isothermal amplification (LAMP) has emerged as a powerful nucleic acid amplification test for the rapid detection of numerous bacterial, fungal, parasitic, and viral agents. Salmonella is a bacterial pathogen of worldwide food safety concern, including food for animals. Presented here is a multi-laboratory-validated Salmonella LAMP protocol that can be used to rapidly screen animal food for the presence of Salmonella contamination and can also be used to confirm presumptive Salmonella isolates recovered from all food categories. The LAMP assay specifically targets the Salmonella invasion gene (invA) and is rapid, sensitive, and highly specific. Template DNAs are prepared from enrichment broths of animal food or pure cultures of presumptive Salmonella isolates. The LAMP reagent mixture is prepared by combining an isothermal master mix, primers, DNA template, and water. The LAMP assay runs at a constant temperature of 65 &#176;C for 30 min. Positive results are monitored via real-time fluorescence and can be detected as early as 5 min. The LAMP assay exhibits high tolerance to inhibitors in animal food or culture medium, serving as a rapid, reliable, robust, cost-effective, and user-friendly method for screening and confirming Salmonella. The LAMP method has recently been incorporated into the U.S. Food and Drug Administration&#8217;s Bacteriological Analytical Manual (BAM) Chapter 5.

Loop-Mediated Isothermal Amplification for Screening Salmonella in Animal Food and Confirming Salmonella from Culture Isolation

Loop-mediated isothermal amplification (LAMP) is an isothermal nucleic acid amplification test (iNAAT) that has attracted broad interest in the pathogen detection field. Here, we present a multi-laboratory-validated Salmonella LAMP protocol as a rapid, reliable, and robust method for screening Salmonella in animal food and confirming presumptive Salmonella from culture isolation.

Loop-mediated isothermal amplification (LAMP) has emerged as a powerful nucleic acid amplification test for the rapid detection of numerous bacterial, ...