Name: optimization for sequencing and analysis of degraded ffpe-rna samples
Uploaded: 2020-06-08T15:00:00
Description: Watch this Scientific Journal Video about Optimization for Sequencing and Analysis of Degraded FFPE-RNA Samples at JoVE.com

Vi er taknemmelige for at Dr. Danielle Carrick (Division of Cancer Control og Befolkning Sciences, National Cancer Institute) for fortsat hjælp, især for at indlede denne undersøgelse, der giver os prøverne, og for nyttige forslag under dataanalyse. Vi oprigtigt takke alle medlemmer af CCR Sekventering Facility på Frederick National Laboratory for Cancer Research for deres hjælp under prøve forberedelse og sekventering, især Brenda Ho for bistand i prøve QC, Oksana tysk for biblioteket QC, Tatyana Smirnova for at køre sequencers. Vi vil også gerne takke Tsai-wei Shen og Ashley Walton på Sequencing Facility Bioinformatics Group for at hjælpe med dataanalyse og implementering af RNA-seq-rørledning. Vi takker også CCBR og NCBR for hjælp med RNaseq analyse pipeline og bedste praksis udvikling.

1. RNA-kvantitet og kvalitetsvurdering
<ol><li>Udvælg FFPE-prøverne efter foruddefinerede kriterier, og ekstrakt RNA udeksembes ved hjælp af en passende metode (f.eks. FFPE-nukleinsyreekstraktionssæt, tabel over materialer). BEMÆRK: Der findes flere forskellige metoder til FFPE-RNA-ekstraktion, herunder de nyere mikrodissectionmetoder, der kan arbejde med meget lidt væv og udtrække RNA12,13,,14.</li>...

<ol>
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D., Shyr, Y., Guo, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Utilization+of+Formalin+Fixed-Paraffin-Embedded+Specimens+in+High+Throughput+Genomic+Studies.">The Utilization of Formalin Fixed-Paraffin-Embedded Specimens in High Throughput Genomic Studies.</a> International Journal of Genomics. 2017, 1926304 (2017).</li><li>Srinivasan, M., Sedmak, D., Jewell, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+fixatives+and+tissue+processing+on+the+content+and+integrity+of+nucleic+acids.">Effect of fixatives and tissue processing on the content and integrity of nucleic acids.</a> American Journal of Pathology. 161 (6), 1961-1971 (2002).</li><li>von Ahlfen, S., Missel, A., Bendrat, K., Schlumpberger, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determinants+of+RNA+quality+from+FFPE+samples.">Determinants of RNA quality from FFPE samples.</a> PLoS One. 2 (12), 1261 (2007).</li><li>Esteve-Codina, 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=A+Comparison+of+RNA-Seq+Results+from+Paired+Formalin-Fixed+Paraffin-Embedded+and+Fresh-Frozen+Glioblastoma+Tissue+Samples.">A Comparison of RNA-Seq Results from Paired Formalin-Fixed Paraffin-Embedded and Fresh-Frozen Glioblastoma Tissue Samples.</a> PLoS One. 12 (1), 0170632 (2017).</li><li>Vukmirovic, 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=Identification+and+validation+of+differentially+expressed+transcripts+by+RNA-sequencing+of+formalin-fixed,+paraffin-embedded+(FFPE)+lung+tissue+from+patients+with+Idiopathic+Pulmonary+Fibrosis.">Identification and validation of differentially expressed transcripts by RNA-sequencing of formalin-fixed, paraffin-embedded (FFPE) lung tissue from patients with Idiopathic Pulmonary Fibrosis.</a> BMC Pulmonary Medicine. 17 (1), 15 (2017).</li><li>Adiconis, X., 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=Comparative+analysis+of+RNA+sequencing+methods+for+degraded+or+low-input+samples.">Comparative analysis of RNA sequencing methods for degraded or low-input samples.</a> Nature Methods. 10 (7), 623-629 (2013).</li><li>Sinicropi, D., 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=Whole+transcriptome+RNA-Seq+analysis+of+breast+cancer+recurrence+risk+using+formalin-fixed+paraffin-embedded+tumor+tissue.">Whole transcriptome RNA-Seq analysis of breast cancer recurrence risk using formalin-fixed paraffin-embedded tumor tissue.</a> PLoS One. 7 (7), 40092 (2012).</li><li>Altekruse, S. F., 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=SEER+cancer+registry+biospecimen+research:+yesterday+and+tomorrow.">SEER cancer registry biospecimen research: yesterday and tomorrow.</a> Cancer Epidemiology, Biomarkers &amp; Prevention. 23 (12), 2681-2687 (2014).</li><li>Zhao, Y., 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=Robustness+of+RNA+sequencing+on+older+formalin-fixed+paraffin-embedded+tissue+from+high-grade+ovarian+serous+adenocarcinomas.">Robustness of RNA sequencing on older formalin-fixed paraffin-embedded tissue from high-grade ovarian serous adenocarcinomas.</a> PLoS One. 14 (5), 0216050 (2019).</li><li>Amini, 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=An+optimised+protocol+for+isolation+of+RNA+from+small+sections+of+laser-capture+microdissected+FFPE+tissue+amenable+for+next-generation+sequencing.">An optimised protocol for isolation of RNA from small sections of laser-capture microdissected FFPE tissue amenable for next-generation sequencing.</a> BMC Molecular Biology. 18 (1), 22 (2017).</li><li>Amini, P., Nassiri, S., Ettlin, J., Malbon, A., Markkanen, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Next-generation+RNA+sequencing+of+FFPE+subsections+reveals+highly+conserved+stromal+reprogramming+between+canine+and+human+mammary+carcinoma.">Next-generation RNA sequencing of FFPE subsections reveals highly conserved stromal reprogramming between canine and human mammary carcinoma.</a> Disease Models and Mechanisms. 12 (8), (2019).</li><li>Wimmer, 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=Systematic+evaluation+of+RNA+quality,+microarray+data+reliability+and+pathway+analysis+in+fresh,+fresh+frozen+and+formalin-fixed+paraffin-embedded+tissue+samples.">Systematic evaluation of RNA quality, microarray data reliability and pathway analysis in fresh, fresh frozen and formalin-fixed paraffin-embedded tissue samples.</a> Scientific Reports. 8 (1), 6351 (2018).</li><li>. Babraham Bioinformatics Available from: <a target="_blank" href="https://www.bioinformatics.babraham.ac.uk/projects/fastqc/">https://www.bioinformatics.babraham.ac.uk/projects/fastqc/</a> (2019)</li><li>Martin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cutadapt+removes+adapter+sequences+from+high-throughput+sequencing+reads.">Cutadapt removes adapter sequences from high-throughput sequencing reads.</a> EMBnet.journal. 17 (1), 10-12 (2011).</li><li>Bolger, A. M., Lohse, M., Usadel, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trimmomatic:+a+flexible+trimmer+for+Illumina+sequence+data.">Trimmomatic: a flexible trimmer for Illumina sequence data.</a> Bioinformatics. 30 (15), 2114-2120 (2014).</li><li>. Babraham Bioinformatics Available from: <a target="_blank" href="https://www.bioinformatics.babraham.ac.uk/projects/fastq_screen/">https://www.bioinformatics.babraham.ac.uk/projects/fastq_screen/</a> (2019)</li><li>Wood, D. E., Salzberg, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kraken:+ultrafast+metagenomic+sequence+classification+using+exact+alignments.">Kraken: ultrafast metagenomic sequence classification using exact alignments.</a> Genome Biology. 15 (3), 46 (2014).</li><li>Dobin, 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=STAR:+ultrafast+universal+RNA-seq+aligner.">STAR: ultrafast universal RNA-seq aligner.</a> Bioinformatics. 29 (1), 15-21 (2013).</li><li>Wang, L., Wang, S., Li, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RSeQC:+quality+control+of+RNA-seq+experiments.">RSeQC: quality control of RNA-seq experiments.</a> Bioinformatics. 28 (16), 2184-2185 (2012).</li><li>Ewels, P., Magnusson, M., Lundin, S., Kaller, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MultiQC:+summarize+analysis+results+for+multiple+tools+and+samples+in+a+single+report.">MultiQC: summarize analysis results for multiple tools and samples in a single report.</a> Bioinformatics. 32 (19), 3047-3048 (2016).</li><li>Li, B., Dewey, C. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RSEM:+accurate+transcript+quantification+from+RNA-Seq+data+with+or+without+a+reference+genome.">RSEM: accurate transcript quantification from RNA-Seq data with or without a reference genome.</a> BMC Bioinformatics. 12, 323 (2011).</li><li>Son, K., Yu, S., Shin, W., Han, K., Kang, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Simple+Guideline+to+Assess+the+Characteristics+of+RNA-Seq+Data.">A Simple Guideline to Assess the Characteristics of RNA-Seq Data.</a> BioMed Research International. 2018, 2906292 (2018).</li><li>McCarthy, D. J., Chen, Y., Smyth, G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+expression+analysis+of+multifactor+RNA-Seq+experiments+with+respect+to+biological+variation.">Differential expression analysis of multifactor RNA-Seq experiments with respect to biological variation.</a> Nucleic Acids Research. 40 (10), 4288-4297 (2012).</li><li>Robinson, M. D., McCarthy, D. J., Smyth, G. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=edgeR:+a+Bioconductor+package+for+differential+expression+analysis+of+digital+gene+expression+data.">edgeR: a Bioconductor package for differential expression analysis of digital gene expression data.</a> Bioinformatics. 26 (1), 139-140 (2010).</li><li>Ritchie, M. 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=limma+powers+differential+expression+analyses+for+RNA-sequencing+and+microarray+studies.">limma powers differential expression analyses for RNA-sequencing and microarray studies.</a> Nucleic Acids Research. 43 (7), 47 (2015).</li><li>Subramanian, 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=Gene+set+enrichment+analysis:+a+knowledge-based+approach+for+interpreting+genome-wide+expression+profiles.">Gene set enrichment analysis: a knowledge-based approach for interpreting genome-wide expression profiles.</a> Proceedings of the National Academy of Sciences of the United States of America U S A. 102 (43), 15545-15550 (2005).</li><li>Mootha, V. 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=PGC-1alpha-responsive+genes+involved+in+oxidative+phosphorylation+are+coordinately+downregulated+in+human+diabetes.">PGC-1alpha-responsive genes involved in oxidative phosphorylation are coordinately downregulated in human diabetes.</a> Nature Genetics. 34 (3), 267-273 (2003).</li><li>Ashburner, 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=Gene+ontology:+tool+for+the+unification+of+biology.+The+Gene+Ontology+Consortium.">Gene ontology: tool for the unification of biology. The Gene Ontology Consortium.</a> Nature Genetics. 25 (1), 25-29 (2000).</li><li>Huang da, W., Sherman, B. T., Lempicki, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systematic+and+integrative+analysis+of+large+gene+lists+using+DAVID+bioinformatics+resources.">Systematic and integrative analysis of large gene lists using DAVID bioinformatics resources.</a> Nature Protocols. 4 (1), 44-57 (2009).</li><li>Huang da, W., Sherman, B. T., Lempicki, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioinformatics+enrichment+tools:+paths+toward+the+comprehensive+functional+analysis+of+large+gene+lists.">Bioinformatics enrichment tools: paths toward the comprehensive functional analysis of large gene lists.</a> Nucleic Acids Research. 37 (1), 1-13 (2009).</li><li>Evaluating RNA Quality from FFPE Samples. Illumina Available from: <a target="_blank" href="https://www.illumina.com/content/dam/illumina-marketing/documents/products/technotes/evaluating-rna-quality-from-ffpe-samples-technical-note-470-2014-001.pdf">https://www.illumina.com/content/dam/illumina-marketing/documents/products/technotes/evaluating-rna-quality-from-ffpe-samples-technical-note-470-2014-001.pdf</a> (2016)</li></ol>

Den metode, der er beskrevet her, skitserer de vigtigste trin, der kræves for at opnå gode sekvensdata fra FFPE-RNA-prøver. De vigtigste punkter, der skal overvejes med denne metode, er: 1) Sørg for, at RNA'et bevares bedst muligt efter ekstraktionen ved at minimere prøvehåndteringen og fryse- og optøningscyklusserne. Separate QC aliquots er meget hjælpsomme. (2) Brug en QC-metrikværdi, der er bedst for det givne stikprøvesæt. RIN-værdier og DV200 er ofte ikke nyttige for nedbrudte prøver, og DV<s...

Brug af næste generations sekventeringsmetoder har gjort det muligt for os at indsamle et væld af oplysninger fra forskellige typer prøver. Gamle og dårligt bevarede prøver forbliver dog uigennemførlige for de almindeligt anvendte metoder til generering af sekvensdata og kræver ofte ændringer af veletablerede protokoller. FFPE-væv repræsenterer en sådan prøvetype , som er blevet anvendt i vid udstrækning til kliniske prøver1,2,3. Mens FFPE konservering fastholder væv morfologi, nukleinsyrer i FFPE væv normalt udviser en bred vifte af skader og nedbrydning, hvilket gør det vanskeligt at hente den genomiske oplysninger, der kan føre til vigtige indsigter om molekylære mekanismer, der ligger til grund for forskellige lidelser.
Genekspressionsdata genereret af RNA-sekvensering er ofte medvirkende til at studere sygdoms- og resistensmekanismer og supplerer DNA-mutationsanalyse. Men RNA er mere modtagelig for nedbrydning, hvilket gør det mere udfordrende at generere nøjagtige genekspressionsdata fra FFPE-væv. Da sekvensering er forholdsvis ny, blev ældre prøver desuden ofte ikke opbevaret under forhold, der var nødvendige for at bevare RNA-integriteten. Nogle af problemerne med FFPE-prøver omfatter nedbrydning af RNA på grund af indlejring i paraffin, kemisk modifikation af RNA, der fører til fragmentering eller refractoriness til enzymatiske processer, der kræves til sekventering, og tab af poly-A haler, begrænse anvendeligheden af oligo-dT som primer for omvendt transkription4. En anden udfordring er håndtering/opbevaring af FFPE-prøver under suboptimale forhold, hvilket kan føre til yderligere nedbrydning af labile molekyler som RNA i væv5. Dette er især relevant for ældre prøver, der kan være indsamlet på et tidspunkt, hvor der ikke blev forudset genekspressionsanalyse ved RNA-sekvensering for prøverne. Alle disse fører til nedsat kvalitet og kvantitet af det udtrukne RNA til rådighed til at generere nyttige sekvensdata. Den lave sandsynlighed for succes, kombineret med de høje omkostninger ved sekventering, har afskrækket mange forskere fra at forsøge at generere og analysere genekspressionsdata fra potentielt nyttige FFPE-prøver. Nogle undersøgelser i de senere år har vist, at FFPE-væv er anvendeligt til genekspressionsanalyse2,,6,7,8,9, om end for færre og/eller nyere prøver.
Som en forundersøgelse brugte vi RNA udvundet fra FFPE tumorvævsprøver fra tre residualvævslagre fra overvågning, epidemiologi og slutresultater (SEER) kræftregistre til RNA-sekventering og genekspressionsanalyse10. FFPE-væv fra højkvalitets ovarieserøse adenocarcinomer blev opbevaret fra 7-32 år under forskellige forhold før RNA-ekstraktion. Fordi disse blokke i de fleste tilfælde havde været opbevaret på forskellige steder i årevis uden forventning om nogen følsom genetisk analyse i fremtiden, var der ikke blevet taget megen hensyn til at bevare nukleinsyrerne. Således udviste de fleste prøver RNA af dårlig kvalitet, og en stor del af prøverne var forurenet med bakterier. Ikke desto mindre var vi i stand til at udføre gen kvantificering, måle ensartethed og kontinuitet i gendækning, og udføre Pearson korrelationsanalyse blandt biologiske replikater til at måle reproducerbarhed. Baseret på et sæt af centrale signatur gen panel, sammenlignede vi prøverne i vores undersøgelse med The Cancer Genome Atlas (TCGA) data og bekræftede, at ca 60% af prøverne havde sammenlignelige genekspression profiler11. Baseret på sammenhængen mellem forskellige QC-resultater og prøvemetadata identificerede vi vigtige QC-målinger, der har en god prædiktiv værdi til identifikation af prøver, der er mere tilbøjelige til at generere brugbare sekvensdata11.
Her beskriver vi den metode, der anvendes til FFPE-RNA-kvalitetsvurdering, generering af sekventeringsbiblioteker fra udvundet RNA-prøver og bioinformatikanalyse af sekventeringsdataene.

<table>
	<tbody>
		<tr>
			<td>2100 Bioanalyzer</td>
			<td>Agilent</td>
			<td>G2939BA</td>
			<td></td>
		</tr>
		<tr>
			<td>Agilent DNA 7500 Kit</td>
			<td>Agilent</td>
			<td>5067-1506</td>
			<td></td>
		</tr>
		<tr>
			<td>Agilent High Sensitivity DNA Kit</td>
			<td>Agilent</td>
			<td>5067-4626</td>
			<td></td>
		</tr>
		<tr>
			<td>Agilent RNA 6000 Nano Kit</td>
			<td>Agilent</td>
			<td>5067-1511</td>
			<td></td>
		</tr>
		<tr>
			<td>AllPrep DNA/RNA FFPE Kit</td>
			<td>Qiagen</td>
			<td>80234</td>
			<td></td>
		</tr>
		<tr>
			<td>CFX96 Touch System</td>
			<td>Bio-Rad</td>
			<td>1855195</td>
			<td></td>
		</tr>
		<tr>
			<td>Library Quantification kit v2-Illumina</td>
			<td>KapaBiosystems</td>
			<td>KK4824</td>
			<td></td>
		</tr>
		<tr>
			<td>NEBNext Ultra II Directional RNA Library Prep Kit for Illumina</td>
			<td>New England Biolabs</td>
			<td>E7765S</td>
			<td>https://www.neb.com/protocols/2017/02/07/protocol-for-use-with-ffpe-rna-nebnext-rrna-depletion-kit</td>
		</tr>
		<tr>
			<td>NEBNext rRNA Depletion Kit (Human/Mouse/Rat)</td>
			<td>New England Biolabs</td>
			<td>E6310L</td>
			<td></td>
		</tr>
		<tr>
			<td>NextSeq 500 Sequencing System</td>
			<td>Illumina</td>
			<td>SY-415-1001</td>
			<td>NextSeq 500 System guide: https://support.illumina.com/content/dam/illumina-support/documents/documentation/system_documentation/nextseq/nextseq-500-system-guide-15046563-06.pdf</td>
		</tr>
		<tr>
			<td>NextSeq PhiX Control Kit</td>
			<td>Illumina</td>
			<td>FC-110-3002</td>
			<td></td>
		</tr>
		<tr>
			<td>NSQ 500/550 Hi Output KT v2.5 (150 CYS)</td>
			<td>Illumina</td>
			<td>20024907</td>
			<td></td>
		</tr>
		<tr>
			<td>10X Genomics Magnetic Separator</td>
			<td>10X Genomics</td>
			<td>120250</td>
			<td></td>
		</tr>
		<tr>
			<td>Rotator Multimixer</td>
			<td>VWR</td>
			<td>13916-822</td>
			<td></td>
		</tr>
		<tr>
			<td>C1000 Touch Thermal Cycler</td>
			<td>Bio-Rad</td>
			<td>1851197</td>
			<td></td>
		</tr>
		<tr>
			<td>Sequencing reagent kit</td>
			<td>Illumina</td>
			<td>20024907</td>
			<td></td>
		</tr>
		<tr>
			<td>Flow cell package</td>
			<td>Illumina</td>
			<td>20024907</td>
			<td></td>
		</tr>
		<tr>
			<td>Buffer cartridge and the reagent cartridge</td>
			<td>Illumina</td>
			<td>20024907</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide solution (0.2N)</td>
			<td>Millipore Sigma</td>
			<td>SX0607D-6</td>
			<td></td>
		</tr>
		<tr>
			<td>TRIS-HCL Buffer 1.0M, pH 7.0</td>
			<td>Fisher Scientific</td>
			<td>50-151-871</td>
			<td></td>
		</tr>
	</tbody>
</table>

optimization for sequencing and analysis of degraded ffpe-rna samples

Genekspressionsanalyse ved RNA-sekventering (RNA-seq) giver unik indsigt i kliniske prøver, der potentielt kan føre til mekanistisk forståelse af grundlaget for forskellige sygdomme samt resistens- og/eller modtagelighedsmekanismer. FFPE-væv, som repræsenterer den mest almindelige metode til konservering af vævsmorfologi i kliniske prøver, er imidlertid ikke de bedste kilder til analyse af genekspressionsprofilering. RNA fremstillet af sådanne prøver er ofte nedbrudt, fragmenteret og kemisk modificeret, hvilket fører til suboptimale sekventering biblioteker. Til gengæld genererer disse sekvensdata af dårlig kvalitet, som måske ikke er pålidelige til genekspressionsanalyse og mutationsopdagelse. For at få mest muligt ud af FFPE-prøver og få de bedst mulige data fra prøver af lav kvalitet er det vigtigt at tage visse forholdsregler, mens man planlægger eksperimentelt design, forbereder sekventeringsbiblioteker og under dataanalyse. Dette omfatter brug af relevante målinger til præcis stikprøvekvalitetskontrol (QC), identificere de bedste metoder til forskellige trin under sekvensering bibliotek generation, og omhyggelig bibliotek QC. Desuden er det afgørende at anvende korrekte softwareværktøjer og parametre til sekvensdataanalyse for at identificere artefakter i RNA-seq-data, bortfiltrere forurening og lavkvalitetsaflæsninger, vurdere ensartetheden af gendækningen og måle reproducerbarheden af genekspressionsprofiler blandt biologiske replikater. Disse trin kan sikre høj nøjagtighed og reproducerbarhed til profilering af meget heterogene RNA-prøver. Her beskriver vi de forskellige trin til prøve QC, bibliotek forberedelse og QC, sekventering, og dataanalyse, der kan bidrage til at øge mængden af nyttige data fra lav kvalitet RNA, som den, der opnås fra FFPE-RNA væv.

Den ovenfor beskrevne metode blev anvendt på 67 FFPE-prøver, der havde været opbevaret under en række forskellige betingelser i 7-32 år (medianprøvelagringstiden var 17,5 år). De datasæt og analyseresultater, der præsenteres her , er tidligere beskrevet og offentliggjort i Zhao et al.11. Ved kontrol af prøvekvaliteten som beskrevet tidligere (dvs. eksempelspor i figur 2) blev DV100 anset for at være mere nyttig end DV200, fordi den er ...

Watch this Scientific Journal Video about Optimization for Sequencing and Analysis of Degraded FFPE-RNA Samples at JoVE.com

Optimization for Sequencing and Analysis of Degraded FFPE-RNA Samples

Denne metode beskriver de trin til at forbedre kvaliteten og kvantiteten af sekvensdata, der kan fås fra formalin-faste paraffin-indlejrede (FFPE) RNA-prøver. Vi beskriver metoden til mere præcist at vurdere kvaliteten af FFPE-RNA-prøver, udarbejde sekventeringsbiblioteker og analysere data fra FFPE-RNA-prøver.

Optimering til sekventering og analyse af forringede FFPE-RNA-prøver

Gene expression analysis by RNA sequencing (RNA-seq) enables unique insights into clinical samples that can potentially lead to mechanistic understanding ...

Vores protokol kan bruges til at forbedre kvaliteten og kvantiteten af genudfoldelsesdata genereret fra FFPE-afledte RNA-prøver, især i suboptimale kvalitetsprøver. Denne teknik vurderer RNA-kvaliteten i FFPE-vævsprøver og gør det muligt at optimere deres downstream-behandling for at forbedre mængden og kvaliteten af stikprøvesekventeringsdataene. Denne metode gør det muligt at beskrive en udskrift i biologisk og klinisk prøve og kan give indsigt i funktionelle elementer af genomet i udvikling og sygdom.FFPE-RNA nedbrydning og udvælgelse af metoder til prøve QC, bibliotek forberedelse, og dataanalyse kan alle være meget vanskelig. Vær omhyggelig, når du vælger de rigtige metoder og passende kontroller. Visuel demonstration giver seerne mulighed for at observere de små subtile ændringer og forholdsregler, der er nødvendige under planlægningen, vurderingen og sekventeringsprocessen, især for dårligt bevarede FFPE-prøver.For at kontrollere kvaliteten af RNA-prøven skal du køre prøven på et RNA QC-system i henhold til producentens anvisninger og bruge den relevante bioanalysesoftware til at analysere distributionen af RNA-fragmenterne i prøven og til at beregne andelen af fragmenter, der er længere end 100 og 200 nukleotider. Baseret på QC-målingerne skal du identificere prøverne med mindre end 40 % af fragmenterne på over 100 nukleotider for at udelukke disse prøver fra behandling. For sekvensering optø de relevante reagenssæt i rækkefølge i henhold til kørselsparametrene i et rumtemperaturvandbad, og reagensbakken sættes på fire grader Celsius efter optøning.Flowcellepakken skal være placeret ved stuetemperatur i 30 minutter. Mens pakken er opvarmning, skal du åbne Illumina Experiment Manager-programmet og vælge Opret eksempelark. Vælg den sequencer, der skal bruges, og klik på Næste.Angiv stregkoden på reagenssættet og de andre relevante arbejdsgangsparametre. Overfør derefter et eksempelark, der er oprettet i henhold til Illumina-sekvenskriterierne. For at forberede prøvebiblioteket og kontrolbiblioteket PhiX skal bibliotekerne dule og fortyndes til de relevante koncentrationer og blande prøven og PhiX-kontrolbibliotekerne for at opnå et 5% PhiX kontrolvolumenforhold.Når flowcellerne er klar, fjernes indpakningen, glasoverfladen rengør den med en fnugfri alkoholtørning, og glasset tørres med et lavt fnuglaboratorium. Fjern reagenspatronen fra fire grader Celsius-opbevaring, og inverter patronen fem gange for at blande reagenserne. Bank forsigtigt på patronen på bænken for at reducere luftboblerne, og læg den denaturerede og fortyndede prøve i reagenspatronen i den angivne beholder.Læg flowcellen, bufferpatronen og reagenspatronen på systemet. Udfør derefter en automatisk kontrol, og gennemgå outputtet for at sikre, at kørselsparametrene består systemkontrollen. Når den automatiske kontrol er fuldført, skal du vælge start for at starte sekvenskørslen.Hvis du vil visualisere QC-resultaterne for forbehandling og QC efter justeringen, skal du køre multi-QC for at generere en aggregeret rapport i HTML-format. Hvis du vil bestemme batcheffekter og vurdere kvalitetskortet for det givne datasæt, skal du bruge et R-script til at udføre en hovedkomponentanalyse. Prøve korrelationsanalyse kan derefter udføres ved hjælp af Pearson korrelation mellem forskellige prøver.Vurderingen af andelen af fragmenter, der er længere end 100 nukleotider, er mere nyttigt end et skøn over fragmenterne længere end 200 nukleotider, fordi det er mere følsomt til nøjagtig måling af andelen af mindre fragmentstørrelser for stærkt nedbrudte RNA-prøver. I betragtning af den høje grad af nedbrydning i prøvesættet anbefales en samlet RNA-biblioteksforberedelsesmetode. For eksempel vises sekventeringsbiblioteker, der er udarbejdet ud fra fire forskellige eksempler.Her vises oversigter over rå FastQ-filsekventeringskvalitet og eksempeladapterindhold. FastQC screening kan hjælpe med at opdage forurening såsom bakteriel eller mus forurening i prøverne. STAR-justering kan bruges til at bestemme andelen af læsninger, der er knyttet til referencegenomet, procentdelen af læsninger, der entydigt er knyttet til referencegenomet, og andelen af læsninger, der ikke er tilknyttet, eller som er knyttet til flere loci.Kortet og RSeQC statistikker kan bruges til at bestemme procentdelen af messenger RNAs, intronic og intergene baser til stede i den kortlagte læser. For disse repræsentative analyser, nogle forringede biblioteker havde en tre prime bias, hvor flere læser blev kortlagt tættere på de tre prime end til de fem primære ende. Desuden kan der udføres hovedkomponentanalyse for at bestemme procentdelen af den samlede variation, der er registreret af de vigtigste komponenter for de biologiske replikater af hver prøve.Pas på for at undgå prøveforringelse, forberede replikater og flere lag for hver prøve, bruge de relevante målinger til at vurdere prøvens kvalitet og bruge den rigtige biblioteksforberedelsesmetode. Ved hjælp af denne metode, større NGS undersøgelser kan udføres med tidligere ubrugelige FFPE prøver med varierende opbevaringstider og betingelser for at få indsigt i en række forskellige sygdom stater. Denne teknik banede vejen for forskere at studere eksisterende store arkiver FFPE prøve med rige kliniske oplysninger og kan i høj grad forbedre befolkningsbaserede kræftundersøgelser.

optimization-for-sequencing-and-analysis-of-degraded-ffpe-rna-samples

Research

JoVE Journal

Genetics

Flow-sorting and Exome Sequencing of the Reed-Sternberg Cells of Classical Hodgkin Lymphoma

The Hodgkin Reed-Sternberg cells of classical Hodgkin lymphoma are sparsely distributed within a background of inflammatory lymphocytes and typically comprise less than 1% of the tumor mass. Material derived from bulk tumor contains tumor content at a concentration insufficient for characterization. Therefore, fluorescence activated cell sorting using eight antibodies, as well as side- and forward-scatter, is described here as a method of rapidly separating and concentrating with high purity thousands of HRS cells from the tumor for subsequent study. At the same time, because standard protocols for exome sequencing typically require 100-1,000 ng of input DNA, which is often too high, even with flow sorting, we also provide an optimized, low-input library construction protocol capable of producing high-quality data from as little as 10 ng of input DNA. This combination is capable of producing next-generation libraries suitable for hybridization capture of whole-exome baits or more focused targeted panels, as desired. Exome sequencing of the HRS cells, when compared against healthy intratumor T or B cells, can identify somatic alterations, including mutations, insertions and deletions, and copy number alterations. These findings elucidate the molecular biology of HRS cells and may reveal avenues for targeted drug treatments.

Here, we describe a combined flow cytometric cell sorting and low-input, next-generation library construction protocol designed to produce high-quality, whole-exome data from the Hodgkin Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (CHL).

Flowsortering og Exome-sekventering af Reed-Sternberg-cellerne af klassisk Hodgkin-lymfom

The Hodgkin Reed-Sternberg cells of classical Hodgkin lymphoma are sparsely distributed within a background of inflammatory lymphocytes and typically ...

Detection of Copy Number Alterations Using Single Cell Sequencing

Detection of genomic changes at single cell resolution is important for characterizing genetic heterogeneity and evolution in normal tissues, cancers, and microbial populations. Traditional methods for assessing genetic heterogeneity have been limited by low resolution, low sensitivity, and/or low specificity. Single cell sequencing has emerged as a powerful tool for detecting genetic heterogeneity with high resolution, high sensitivity and, when appropriately analyzed, high specificity. Here we provide a protocol for the isolation, whole genome amplification, sequencing, and analysis of single cells. Our approach allows for the reliable identification of megabase-scale copy number variants in single cells. However, aspects of this protocol can also be applied to investigate other types of genetic alterations in single cells.

Single cell sequencing is an increasingly popular and accessible tool for addressing genomic changes at high resolution. We provide a protocol that uses single cell sequencing to identify copy number alterations in single cells.

Påvisning af Copy Number Ændringer Brug Single Cell Sequencing

Detection of genomic changes at single cell resolution is important for characterizing genetic heterogeneity and evolution in normal tissues, cancers, and ...

Optimization and Comparative Analysis of Plant Organellar DNA Enrichment Methods Suitable for Next-generation Sequencing

Plant organellar genomes contain large, repetitive elements that may undergo pairing or recombination to form complex structures and/or sub-genomic fragments. Organellar genomes also exist in admixtures within a given cell or tissue type (heteroplasmy), and an abundance of subtypes may change throughout development or when under stress (sub-stoichiometric shifting). Next-generation sequencing (NGS) technologies are required to obtain deeper understanding of organellar genome structure and function. Traditional sequencing studies use several methods to obtain organellar DNA: (1) If a large amount of starting tissue is used, it is homogenized and subjected to differential centrifugation and/or gradient purification. (2) If a smaller amount of tissue is used (i.e., if seeds, material, or space is limited), the same process is performed as in (1), followed by whole-genome amplification to obtain sufficient DNA. (3) Bioinformatics analysis can be used to sequence the total genomic DNA and to parse out organellar reads. All these methods have inherent challenges and tradeoffs. In (1), it may be difficult to obtain such a large amount of starting tissue; in (2), whole-genome amplification could introduce a sequencing bias; and in (3), homology between nuclear and organellar genomes could interfere with assembly and analysis. In plants with large nuclear genomes, it is advantageous to enrich for organellar DNA to reduce sequencing costs and sequence complexity for bioinformatics analyses. Here, we compare a traditional differential centrifugation method with a fourth method, an adapted CpG-methyl pulldown approach, to separate the total genomic DNA into nuclear and organellar fractions. Both methods yield sufficient DNA for NGS, DNA that is highly enriched for organellar sequences, albeit at different ratios in mitochondria and chloroplasts. We present the optimization of these methods for wheat leaf tissue and discuss major advantages and disadvantages of each approach in the context of sample input, protocol ease, and downstream application.

The comparison and optimization of two plant organellar DNA enrichment methods are presented: traditional differential centrifugation and fractionation of the total gDNA based on methylation status. We assess the resulting DNA quantity and quality, demonstrate performance in short-read next-generation sequencing, and discuss the potential for use in long-read single-molecule sequencing.

Optimering og sammenligningsanalyse af planteorganell DNA-berigelsesmetoder egnet til næste generations sekventering

Plant organellar genomes contain large, repetitive elements that may undergo pairing or recombination to form complex structures and/or sub-genomic ...

Generation of Native Chromatin Immunoprecipitation Sequencing Libraries for Nucleosome Density Analysis

We present a modified native chromatin immunoprecipitation sequencing (ChIP-seq) experimental protocol compatible with a Gaussian mixture distribution based analysis methodology (nucleosome density ChIP-seq; ndChIP-seq) that enables the generation of combined measurements of micrococcal nuclease (MNase) accessibility with histone modification genome-wide. Nucleosome position and local density, and the posttranslational modification of their histone subunits, act in concert to regulate local transcription states. Combinatorial measurements of nucleosome accessibility with histone modification generated by ndChIP-seq allows for the simultaneous interrogation of these features. The ndChIP-seq methodology is applicable to small numbers of primary cells inaccessible to cross-linking based ChIP-seq protocols. Taken together, ndChIP-seq enables the measurement of histone modification in combination with local nucleosome density to obtain new insights into shared mechanisms that regulate RNA transcription within rare primary cell populations.

We present a modified native chromatin immunoprecipitation sequencing (ChIP-seq) methodology for the generation of sequence datasets suitable for a nucleosome density ChIP-seq analytical framework integrating micrococcal nuclease (MNase) accessibility with histone modification measurements.

Generation af indfødte kromatin Immunoprecipitation sekventering biblioteker for Nucleosome tæthed analyse

We present a modified native chromatin immunoprecipitation sequencing (ChIP-seq) experimental protocol compatible with a Gaussian mixture distribution ...

Chromatin Immunoprecipitation (ChIP) Protocol for Low-abundance Embryonic Samples

Chromatin immunoprecipitation (ChIP) is a widely-used technique for mapping the localization of post-translationally modified histones, histone variants, transcription factors, or chromatin-modifying enzymes at a given locus or on a genome-wide scale. The combination of ChIP assays with next-generation sequencing (i.e., ChIP-Seq) is a powerful approach to globally uncover gene regulatory networks and to improve the functional annotation of genomes, especially of non-coding regulatory sequences. ChIP protocols normally require large amounts of cellular material, thus precluding the applicability of this method to investigating rare cell types or small tissue biopsies. In order to make the ChIP assay compatible with the amount of biological material that can typically be obtained in vivo during early vertebrate embryogenesis, we describe here a simplified ChIP protocol in which the number of steps required to complete the assay were reduced to minimize sample loss. This ChIP protocol has been successfully used to investigate different histone modifications in various embryonic chicken and adult mouse tissues using low to medium cell numbers (5 x 104 - 5 x 105 cells). Importantly, this protocol is compatible with ChIP-seq technology using standard library preparation methods, thus providing global epigenomic maps in highly relevant embryonic tissues.

Chromatin Immunoprecipitation ChIP Protocol for Low-abundance Embryonic Samples

Here, we describe a chromatin immunoprecipitation (ChIP) and ChIP-seq library preparation protocol to generate global epigenomic profiles from low-abundance chicken embryonic samples.

Kromatin Immunoprecipitation (ChIP) protokol for lav-overflod embryonale prøver

Chromatin immunoprecipitation (ChIP) is a widely-used technique for mapping the localization of post-translationally modified histones, histone variants, ...

Robust DNA Isolation and High-throughput Sequencing Library Construction for Herbarium Specimens

Herbaria are an invaluable source of plant material that can be used in a variety of biological studies. The use of herbarium specimens is associated with a number of challenges including sample preservation quality, degraded DNA, and destructive sampling of rare specimens. In order to more effectively use herbarium material in large sequencing projects, a dependable and scalable method of DNA isolation and library preparation is needed. This paper demonstrates a robust, beginning-to-end protocol for DNA isolation and high-throughput library construction from herbarium specimens that does not require modification for individual samples. This protocol is tailored for low quality dried plant material and takes advantage of existing methods by optimizing tissue grinding, modifying library size selection, and introducing an optional reamplification step for low yield libraries. Reamplification of low yield DNA libraries can rescue samples derived from irreplaceable and potentially valuable herbarium specimens, negating the need for additional destructive sampling and without introducing discernible sequencing bias for common phylogenetic applications. The protocol has been tested on hundreds of grass species, but is expected to be adaptable for use in other plant lineages after verification. This protocol can be limited by extremely degraded DNA, where fragments do not exist in the desired size range, and by secondary metabolites present in some plant material that inhibit clean DNA isolation. Overall, this protocol introduces a fast and comprehensive method that allows for DNA isolation and library preparation of 24 samples in less than 13 h, with only 8 h of active hands-on time with minimal modifications.

This article demonstrates a detailed protocol for DNA isolation and high-throughput sequencing library construction from herbarium material including rescue of exceptionally poor-quality DNA.

Robust DNA isoleret og høj overførselshastighed sekventering bibliotek konstruktion til Herbarium prøver

Herbaria are an invaluable source of plant material that can be used in a variety of biological studies. The use of herbarium specimens is associated with ...

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.

Sjælden begivenhed registrering ved hjælp af fejl-korrigeret DNA og RNA sekventering

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.

Forstærkning af nær fuld længde HIV-1 provirus for næste Generation Sequencing

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

Semiconductor Sequencing for Preimplantation Genetic Testing for Aneuploidy

Chromosomal aneuploidy, one of the main causes leading to embryonic development arrest, implantation failure, or pregnancy loss, has been well documented in human embryos. Preimplantation genetic testing for aneuploidy (PGT-A) is a genetic test that significantly improves reproductive outcomes by detecting chromosomal abnormalities of embryos. Next-generation sequencing (NGS) provides a high-throughput and cost-effective approach for genetic analysis and has shown clinical applicability in PGT-A. Here, we present a rapid and low-cost semiconductor sequencing-based NGS method for screening of aneuploidy in embryos. The first step of the workflow is whole genome amplification (WGA) of the biopsied embryo specimen, followed by construction of sequencing library, and subsequent sequencing on the semiconductor sequencing system. Generally, for a PGT-A application, 24 samples can be loaded and sequenced on each chip generating 60&#8722;80 million reads at an average read length of 150 base pairs. The method provides a refined protocol for performing template amplification and enrichment of sequencing library, making the PGT-A detection reproducible, high-throughput, cost-efficient, and timesaving. The running time of this semiconductor sequencer is only 2&#8722;4 hours, shortening the turnaround time from receiving samples to issuing reports into 5 days. All these advantages make this assay an ideal method to detect chromosomal aneuploidies from embryos and thus, facilitate its wide application in PGT-A.

Here, we introduce a semiconductor sequencing method for preimplantation genetic testing for aneuploidy (PGT-A) with the advantages of short turnaround time, low cost, and high throughput.

Halvleder sekvensering for præimplantations genetisk testning for Aneuploidy

Chromosomal aneuploidy, one of the main causes leading to embryonic development arrest, implantation failure, or pregnancy loss, has been well documented ...

Sequencing of mRNA from Whole Blood using Nanopore Sequencing

Sequencing in remote locations and resource-poor settings presents unique challenges. Nanopore sequencing can be successfully used under such conditions, and was deployed to West Africa during the recent Ebola virus epidemic, highlighting this possibility. In addition to its practical advantages (low cost, ease of equipment transport and use), this technology also provides fundamental advantages over second-generation sequencing approaches, particularly the very long read length, ability to directly sequence RNA, and real-time availability of data. Raw read accuracy is lower than with other sequencing platforms, which represents the main limitation of this technology; however, this can be partially mitigated by the high read depth generated. Here, we present a field-compatible protocol for sequencing of the mRNAs encoding for Niemann-Pick C1, which is the cellular receptor for ebolaviruses. This protocol encompasses extraction of RNA from animal blood samples, followed by RT-PCR for target enrichment, barcoding, library preparation, and the sequencing run itself, and can be easily adapted for use with other DNA or RNA targets.

Nanopore sequencing is a novel technology that allows cost-effective sequencing in remote locations and resource-poor settings. Here, we present a protocol for sequencing of mRNAs from whole blood that is compatible with such conditions.

Sekvensering af mRNA fra fuldblod ved hjælp af Nanopmalm sekvensering

Sequencing in remote locations and resource-poor settings presents unique challenges. Nanopore sequencing can be successfully used under such conditions, ...