Wir danken der gesamten Sigma Life Science Mission Ziel-ID-Bibliothek Entwickler-Team, vor allem Kevin Gutshall für das Finden der Technologie und Verhandlung von Lizenz-und Vertragsbedingungen und Heather Holemon für ihre Unterstützung und Teilnahme an fruchtbaren Diskussionen zur Fehlerbehebung. Wir danken auch Dr. Joop Gäken von King &#39;s College London für den Austausch frei unveröffentlichte Ergebnisse und Anregungen, und Qazi Hamid von RxBiosciences zur Herstellung einer großen Charge von cDNA und seine Beharrlichkeit in immer es geklont. Wir möchten Nan Lin und Scott Bahr aus SAFC anerkennen, zur Durchführung von cDNA-Arrays und Datenanalyse. MISSION ist ein eingetragenes Warenzeichen von Sigma-Aldrich Biotechnology LP

<ol>
	<li>Huang, Q., Gumireddy, K., Schrier, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+microRNAs+miR-373+and+miR-520c+promote+tumour+invasion+and+metastasis.">The microRNAs miR-373 and miR-520c promote tumour invasion and metastasis.</a> Nat. Cell Biol. 10 (2), 202-210 (2008).</li><li>Lichner, Z., Pall, E., Kerekes, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+miR-290-295+cluster+promotes+pluripotency+maintenance+by+regulating+cell+cycle+phase+distribution+in+mouse+embryonic+stem+cells.">The miR-290-295 cluster promotes pluripotency maintenance by regulating cell cycle phase distribution in mouse embryonic stem cells.</a> Differentiation. 81 (1), 11-24 (2011).</li><li>Subramanyam, D., Lamouille, S., Judson, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiple+targets+of+miR-302+and+miR-372+promote+reprogramming+of+human+fibroblasts+to+induced+pluripotent+stem+cells.">Multiple targets of miR-302 and miR-372 promote reprogramming of human fibroblasts to induced pluripotent stem cells.</a> Nat. Biotechnol. 29 (5), 443-448 (2001).</li><li>Lim, L. P., Lau, N. C., Garrett-Engele, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microarray+analysis+shows+that+some+microRNAs+downregulate+large+numbers+of+target+mRNAs.">Microarray analysis shows that some microRNAs downregulate large numbers of target mRNAs.</a> Nature. 433 (7027), 769-773 (2005).</li><li>Huntzinger, E., Izaurralde, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+silencing+by+microRNAs:+contributions+of+translational+repression+and+mRNA+decay.">Gene silencing by microRNAs: contributions of translational repression and mRNA decay.</a> Nat. Rev. Genet. 12 (2), 99-110 (2011).</li><li>Thomas, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Desperately+seeking+microRNA+targets.">Desperately seeking microRNA targets.</a> Nat. Struc. Mol. Biol. 17 (10), 1169-1174 (2010).</li><li>Baek, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+impact+of+microRNAs+on+protein+output.">The impact of microRNAs on protein output.</a> Nature. 455 (7209), 71-71 (2008).</li><li>Guo, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mammalian+microRNAs+predominantly+act+to+decrease+target+mRNA+levels.">Mammalian microRNAs predominantly act to decrease target mRNA levels.</a> Nature. 466 (3708), 835-840 (2010).</li><li>Ma, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumour+invasion+and+metastasis+initiated+my+microRNA-10b+in+breast+cancer.">Tumour invasion and metastasis initiated my microRNA-10b in breast cancer.</a> Nature. 449 (7163), 682-688 (2007).</li><li>Visone, 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=MicroRNAs+miR-221+and+miR-222,+both+overexpressed+in+human+thyroid+papillary+carcinomas,+regulate+p27Kip1+protein+levels+and+cell+cycle.">MicroRNAs miR-221 and miR-222, both overexpressed in human thyroid papillary carcinomas, regulate p27Kip1 protein levels and cell cycle.</a> Endocrine-Related Cancer. 14 (3), 791-798 (2007).</li><li>Lu, Z., 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=MicroRNA-21+promotes+cell+transformation+by+targeting+the+programmed+cell+death+4+gene.">MicroRNA-21 promotes cell transformation by targeting the programmed cell death 4 gene.</a> Oncogene. 27 (31), 4373-4379 (2008).</li><li>Guo, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+noncoding+RNA,+miR-126,+suppresses+the+growth+of+neoplastic+cells+by+targeting+phosphatidylinositol+3-kinase+signaling+and+is+frequently+lost+in+colon+cancers.">The noncoding RNA, miR-126, suppresses the growth of neoplastic cells by targeting phosphatidylinositol 3-kinase signaling and is frequently lost in colon cancers.</a> Genes Chrom. Cancer. 47 (11), 939-946 (2008).</li><li>Yamakuchi, 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=miR-34a+repression+of+SIRT1+regulates+apoptosis.">miR-34a repression of SIRT1 regulates apoptosis.</a> Proc. Natl. Acad. Sci. U.S.A. 105 (36), 13421-13426 (2008).</li><li>Wickramasinghe, N. 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=Estradiol+downregulates+miR-21+expression+and+increases+miR-21+target+gene+expression+in+MCF-7+breast+cancer+cells.">Estradiol downregulates miR-21 expression and increases miR-21 target gene expression in MCF-7 breast cancer cells.</a> Nucleic Acid Res. 37 (8), 2584-2595 .</li><li>Ciaudo, 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=Highly+dynamic+and+sex-specific+expression+of+microRNAs+during+early+ES+cell+differentiation.">Highly dynamic and sex-specific expression of microRNAs during early ES cell differentiation.</a> PLoS Genetics. 5, e1000620 (2009).</li><li>Vallejo, D. 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=Targeting+Notch+signaling+by+the+conserved+miR-8/200+microRNA+family+in+development+and+cancer+cells.">Targeting Notch signaling by the conserved miR-8/200 microRNA family in development and cancer cells.</a> EMBO J. 30 (4), 756-769 (2011).</li><li>Jafarifar, 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=Repression+of+VEGFA+by+CA-rich+element-binding+microRNAs+is+modulated+by+hnRNAP.">Repression of VEGFA by CA-rich element-binding microRNAs is modulated by hnRNAP.</a> L. EMBO J. 30 (7), 1324-1334 (2011).</li><li>Clancy, J. L., 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=mRNA+isoform+diversity+can+obscure+detection+of+miRNA-mediated+control+of+translation.">mRNA isoform diversity can obscure detection of miRNA-mediated control of translation.</a> RNA. 17 (6), 1025-1033 (2011).</li></ol>

Autoren erklären, finanziellen Beziehungen zu Wirtschaftsunternehmen, die ein Interesse an der eingereichten Arbeit zu haben.

Mikro-RNAs sind 20-24 nt-RNAs die Genexpression regulieren posttranskriptional durch die Hemmung der mRNA-Translation und häufig, gezielte Destabilisierung der mRNA (Übersicht in [6]). Ein einzelner miRNA können regeln, mehrere hundert mRNAs einer Zelle Reaktion auf entwicklungs-und umweltpolitischen Signale steuern. Ermittlung und Validierung von Ziel-mRNAs ist von wesentlicher Bedeutung bei der Bestimmung einer miRNA die Rolle und Funktion in dieser Signalwege. Allerdings ist der Target-Identifizierung nicht einfach, weil, bei Tieren, miRNAs und deren Ziel-Seiten sind nicht vollständig komplementär. Der &quot;Seed&quot;-Region, Basen 2 bis 7 aus dem 5&#39;-Ende der miRNA, ist in der Regel komplementär zu seinen Zielen. Allerdings gibt es viele Ausnahmen von der Regel Saatgut, und nachgelagerten Basenpaarung kann für eine unvollkommene Samen Match auszugleichen. Eine Reihe von Computer-Algorithmen wurden entwickelt, um miRNA-Targets auf Seed-Matching-und nachgelagerten Ausgleich, Zielstruktur basiert prognostizieren eind Position, Sequenzkonservierung, und verschiedene andere Parameter, die für experimentell validierten Targets (Übersicht in [7]) beobachtet wurden. Während in silico Vorhersagen bequem sind und nicht identifizieren viele gültige miRNA-Targets, die meisten Gene vorhergesagt ausfallen experimentelle Validierung Tests und vielen tatsächlichen Ziele sind nicht vorhersehbar. Da außerdem Computer-Algorithmen auf vorher bestimmten Ziel-Funktionen basieren, erlauben sie nicht Entdeckung von Zielen, die von dem, was bereits bekannt abweichen. Eine Reihe von experimentellen Systemen wurden erfolgreich zu identifizieren oder zu entdecken funktionelle miRNA-Targets in lebenden Zellen eingesetzt. Diese globalen Screening-Methoden gehören Microarrays und RNA-Sequenzierung, RNA-Co-Immunopräzipitation (RIP) und Markierung mit stabilen Isotopen mit den Aminosäuren in der Zellkultur (SILAC), eine Proteomik-Verfahren (Übersicht in [7]). Jede Methode hat Vor-und Nachteile. Da miRNA-Targeting oft destabilisiert eine mRNA und führt zu dessen Abbau, Verlust or Gewinn an mRNA-Ebene nach der Vorstellung eines miRNA imitieren oder Inhibitor bzw. identifizieren können miRNA-Targets. Dieser Verlust oder Gewinn von mRNA wird leicht durch Microarray-oder tief-Sequenzierung nachgewiesen. Während mRNA Nachweismethoden einfacher und empfindlicher als Protein Nachweismethoden sind, wird mRNA-Nachweis verpassen keine miRNA-Targets, die nicht abgebaut werden. Jüngste Berichte aus dem Labor Bartell Vergleich miRNA Ziel ergibt sich aus RNA-Detektion mit denen aus SILAC [8] oder Ribosomen-Profiling [9] zeigen, dass miRNAs Säugetieren überwiegend durch Reduzierung Ziel-mRNA-Spiegel handeln. Allerdings haben viele andere Labore arbeiten mit einzelnen miRNA Targets Änderung Protein aber keine Änderung in der mRNA-Ebene nachgewiesen werden. Berichte von dem, was offenbar translationale Regulation ohne nachweisbare mRNA-Verlust sind: miR-10b auf HOXD10 [10], miR221/222 auf p27kip1 [11], miR-21 auf Pdcd4 [12], miR-126 auf p85β [13] , miR-34 auf SIRT1 [14], miR-21 auf PTEN [15], miR-302d auf Arid4b [16], miR-200c auf JAG1 [17], und miR-299, 297, 567, einemND 609 auf VEGFA [18]. Darüber hinaus Clancy et al [19] berichtete kürzlich, dass translationale Regulation von let-7 wurde nur erkannt, wenn einzelne mRNA-Isoformen, die die let-7-Ziel-Site enthalten, selektiv detektiert wurden. Letztere legt nahe, dass, zumindest in einigen Fällen, translationale Regulation in einem Verbundprofil übersehen werden - das heißt, wenn alle mRNA-Isoformen als eine mRNA nachgewiesen werden - wie bei vielen Mikroarray und Sequenzanalysen erhalten. Co-Immunpräzipitation von miRNA-mRNA-Komplexe über Argonaut (in der Regel Ago2) oder einem anderen assoziierten Protein (RNA Immunpräzipitation, oder RIP) wird unabhängig von miRNA-Targets Regulationsmechanismus zu isolieren. Darüber hinaus erkennt RIP endogenen und vermutlich biologisch relevante Wechselwirkungen. Es ist jedoch nicht bekannt, ob alle miRNA-mRNA Interaktionen funktionsfähig sind, und würde keine RIP-mRNA-Ziele, die nur vorübergehend zu verbinden oder auch schnell abgebaut zu verpassen. Darüber hinaus müssen spezifische miRNA-mRNA-Partnern geschlossen werden bioinformatitisch, weil alle miRNA-mRNA-Paare kogefällten zusammen. Schließlich SILAC direkt identifiziert das Endprodukt der miRNA-Verordnung, das Protein selbst, ist aber unempfindlich und daher verfehlt selten Proteinen und kleinen Falte Veränderungen im Protein-Spiegel. Vor dem Hintergrund der aktuellen Einschränkungen mit miRNA Target-Identifizierung Methoden, fühlten wir uns eine zusätzliche globale Test auf funktionelle miRNA Targets durch einen alternativen Mechanismus identifizieren, benötigt wurde. Um diesem Bedarf gerecht zu werden, lizenziert wir eine Technologie, die von Joop Gaken und Azim Mohamedali von King &#39;s College London erfunden. Die Erfindung ist ein Dual-Auswahl-Fusionsprotein, insbesondere ein Thymidinkinase-Zeocin-Fusion, reguliert von einem cDNA-Bibliothek potentieller miRNA-Zielsequenzen in der 3&#39;UTR. Zellen, die stabil mit und exprimieren TKzeo-cDNA transfiziert mit Zeocin ausgewählt werden, wie in 2 dargestellt. Nach dem Ausdruck einer miRNA von Interesse, kann, dass miRNA-Ziele ausgewählt werden, with Ganciclovir, wie in Abb. 3 dargestellt. Ganciclovir tötet Zellen, die Thymidinkinase, das heißt, alle Zellen wird TKzeo-cDNA exprimieren, fehlt ein Ziel für die miRNA von Interesse. Gezielte cDNA durch PCR-Amplifikation von DNA aus Zellen, die Ganciclovir unter Verwendung von Primern, die Flanke der cDNA, PCR-Produkte sequenziert und zur Identifizierung von Zielen kann überleben isoliert werden. Missionsziel ID-Bibliothek - Wir haben die King &#39;s College-Technologie in ein neues Tool für die globale Identifikation und Entdeckung der funktionellen humanen miRNA-Targets entwickelt. Mit dem Ziel-ID-Bibliothek kann der Benutzer Zieltranskripte durch eine Reihe von Säugerzellen Transfektion und Arzneimittelselektion Schritte zu isolieren. Die Bibliothek ist umfangreich und enthält 66-79% der menschlichen Gene. Erste Ergebnisse zeigen, dass beide zuvor entdeckt sowie neue Ziele können von der Mission Ziel-ID-Bibliothek isoliert werden. Obwohl das Protokoll ist von einiger Länge,Nutzung der Ziel-ID-Bibliothek erfordert Standard molekulargenetische Labor Techniken - Säugetier-Zellkultur, Transfektion, Medikamentenauswahl, PCR, Sequenzierung und - und sollte daher gut sein, im Rahmen der Möglichkeiten der meisten Biologen. Wir vermuten, dass genügend Aufmerksamkeit, um die ordnungsgemäße experimentelles Design bezahlt werden, die Optimierung der Kulturbedingungen, und am wichtigsten, Pre-Test jedes einzelnen neuen Zelltyp, um eine optimale Wirkstoffspiegel zur Auswahl Schritte (kill-Kurven), um Erfolg mit der Ziel-ID-Bibliothek gewährleisten zu bestimmen. Wie bei allen Ziel-miRNA-Identifikations-Methoden, ist es sehr empfehlenswert, dass die Ziele durch Screening der Ziel-ID identifiziert Bibliothek mit einer zweiten Methode, wie Microarray, qRT-PCR, Reporter-Assay (dh Luciferase) oder Western-Analyse bestätigt werden.

<table border="1" ><tbody><tr><td> Name des Reagenzes </td><td> Firma </td><td> Katalog-Zahl </td><td> Kommentare </td></tr><tr><td> JumpStart REDTaq ReadyMix </td><td> Sigma-Aldrich </td><td> P0982 </td><td></td></tr><tr><td> Ganciclovir </td><td> Sigma-Aldrich </td><td> G2536 </td><td></td></tr><tr><td> G418 </td><td> Sigma-Aldrich </td><td> G8168 </td><td></td></tr><tr><td> Puromycin </td><td> Sigma-Aldrich </td><td> P9620 </td><td></td></tr><tr><td> TOPO TA </td><td> Invitrogen </td><td> KNM4500-01 </td><td></td></tr><tr><td> GenElute genomische Säuger-DNA-Miniprep-Kit </td><td> Sigma-Aldrich </td><td> G1N10 </td><td></td></tr><tr><td> Zellspezifische Nucleofection kes </td><td> Lonza </td><td></td><td></td></tr><tr><td> Nucleofector </td><td> Lonza </td><td> AAD-1001 </td><td></td></tr><tr><td> Zeocin </td><td> Invitrogen </td><td> <a href="http://products.invitrogen.com/ivgn/en/US/adirect/invitrogen?cmd=catProductDetail&amp;productID=R25001">R250-01</a> </td><td></td></tr><tr><td height="1"> Ziel-ID-Bibliothek </td><td> Sigma-Aldrich </td><td> MREH01 </td><td></td></tr></tbody></table>

genome-wide screen for mirna targets using the mission target id library

Die Ziel-ID-Bibliothek wurde entwickelt, um zur Entdeckung und Identifizierung von microRNA (miRNA)-Ziele zu unterstützen. Die Ziel-ID-Bibliothek ist ein Plasmid-basierte, genomweiten cDNA-Bibliothek in der 3&#39;UTR hinter der Dual-Auswahl-Fusionsprotein, Thymidinkinase-Zeocin (TKzeo) kloniert. Die erste Runde der Wahl ist für eine stabile Transformanten, gefolgt mit Einführung einer miRNA von Interesse, und schließlich die Auswahl für die cDNAs mit der miRNA-Ziel. Ausgewählte cDNAs werden durch Sequenzierung (siehe Abbildung 1-3 für die Ziel-ID-Bibliothek und Workflow-Details) identifiziert. Um eine breite Abdeckung des menschlichen Transkriptom zu gewährleisten, wurden Ziel-ID-Bibliothek cDNAs über Oligo-dT-Priming mit einem Pool von Gesamt-RNA aus verschiedenen menschlichen Geweben und Zelllinien hergestellt generiert. Die resultierende cDNA Bereich von 0,5 bis 4 kb, mit einer durchschnittlichen Größe von 1,2 kb, und wurden in die p3TKzeo Dual-Auswahl Plasmid kloniert (siehe 4 für Plasmid-Karte). Die Gen-Targets in der Li vertretenthek kann auf der Sigma-Aldrich Webseite. Ergebnisse von Illumina Sequenzierung (Tabelle 3) zeigen, dass die Bibliothek 16.922 der 21.518 Gene, die in einzigartiger UCSC RefGene (79%) oder 14.000 Genen, die mit 10 oder mehr liest (66%) enthält.

Watch this Scientific Journal Video about Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library at JoVE.com

Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library

Die Ziel-ID-Bibliothek ist ein Plasmid-basierte, Genom-weiten Sammlung von klonierten cDNA verwendet werden, um miRNA-Targets zu identifizieren. Hier zeigen wir, ihre Nutzung und Anwendung.

Genomweiten Screen für miRNA-Targets mit dem Missionsziel ID-Bibliothek

The Target ID Library is designed to assist in discovery and identification of microRNA (miRNA) targets. The Target ID Library is a plasmid-based, ...

genome-wide-screen-for-mirna-targets-using-mission-target-id

Nanyang Technological University

Research

JoVE Journal

Biology

17.5K Aufrufe.  Sigma-Aldrich. Die Ziel-ID-Bibliothek ist ein Plasmid-basierte, Genom-weiten Sammlung von klonierten cDNA verwendet werden, um miRNA-Targets zu identifizieren. Hier zeigen wir, ihre Nutzung und Anwendung.

Serie: Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library

Genome-wide Analysis of Aminoacylation (Charging) Levels of tRNA Using Microarrays

tRNA aminoacylation, or charging, levels can rapidly change within a cell in response to the environment[1]. Changes in tRNA charging levels in both prokaryotic and eukaryotic cells lead to translational regulation which is a major cellular mechanism of stress response. Familiar examples are the stringent response in E. coli and the Gcn2 stress response pathway in yeast ([2-6]). Recent work in E. coli and S. cerevisiae have shown that tRNA charging patterns are highly dynamic and depends on the type of stress experienced by cells [1, 6, 7]. The highly dynamic, variable nature of tRNA charging makes it essential to determine changes in tRNA charging levels at the genomic scale, in order to fully elucidate cellular response to environmental variations. In this review we present a method for simultaneously measuring the relative charging levels of all tRNAs in S. cerevisiae . While the protocol presented here is for yeast, this protocol has been successfully applied for determining relative charging levels in a wide variety of organisms including E. coli and human cell cultures[7, 8].

Genome-wide Analysis of Aminoacylation Charging Levels of tRNA Using Microarrays

We describe a method for microarray analysis to determine relative aminoacylation levels of all tRNAs from S. cerivisiae.

Genomweite Analyse der Aminoacylierung (Charging) Ebenen der tRNA mittels Microarrays

tRNA aminoacylation, or charging, levels can rapidly change within a cell in response to the environment[1]. Changes in tRNA charging levels in both ...

Forschung

Biologie

Genome-wide Analysis using ChIP to Identify Isoform-specific Gene Targets

Recruitment of transcriptional and epigenetic factors to their targets is a key step in their regulation. Prominently featured in recruitment are the protein domains that bind to specific histone modifications. One such domain is the plant homeodomain (PHD), found in several chromatin-binding proteins. The epigenetic factor RBP2 has multiple PHD domains, however, they have different functions (Figure 4). In particular, the C-terminal PHD domain, found in a RBP2 oncogenic fusion in human leukemia, binds to trimethylated lysine 4 in histone H3 (H3K4me3)1. The transcript corresponding to the RBP2 isoform containing the C-terminal PHD accumulates during differentiation of promonocytic, lymphoma-derived, U937 cells into monocytes2. Consistent with both sets of data, genome-wide analysis showed that in differentiated U937 cells, the RBP2 protein gets localized to genomic regions highly enriched for H3K4me33. Localization of RBP2 to its targets correlates with a decrease in H3K4me3 due to RBP2 histone demethylase activity and a decrease in transcriptional activity. In contrast, two other PHDs of RBP2 are unable to bind H3K4me3. Notably, the C-terminal domain PHD of RBP2 is absent in the smaller RBP2 isoform4. It is conceivable that the small isoform of RBP2, which lacks interaction with H3K4me3, differs from the larger isoform in genomic location. The difference in genomic location of RBP2 isoforms may account for the observed diversity in RBP2 function. Specifically, RBP2 is a critical player in cellular differentiation mediated by the retinoblastoma protein (pRB). Consistent with these data, previous genome-wide analysis, without distinction between isoforms, identified two distinct groups of RBP2 target genes: 1) genes bound by RBP2 in a manner that is independent of differentiation; 2) genes bound by RBP2 in a differentiation-dependent manner.
To identify differences in localization between the isoforms we performed genome-wide location analysis by ChIP-Seq. Using antibodies that detect both RBP2 isoforms we have located all RBP2 targets. Additionally we have antibodies that only bind large, and not small RBP2 isoform (Figure 4). After identifying the large isoform targets, one can then subtract them from all RBP2 targets to reveal the targets of small isoform. These data show the contribution of chromatin-interacting domain in protein recruitment to its binding sites in the genome.

Here we are presenting a chromatin immunoprecipitation (ChIP) procedure for genome-wide location analysis of protein isoforms that differ in a histone-binding domain. We are applying it to ChIP-Seq analysis to identify the targets of the KDM5A/JARID1A/RBP2 histone demethylase.

Genomweite Analyse mittels ChIP zu Isoform-spezifische Gene-Targets zu identifizieren

Recruitment of transcriptional and epigenetic factors to their targets is a key step in their regulation. Prominently featured in recruitment are the ...

MISSION LentiPlex Pooled shRNA Library Screening in Mammalian Cells

RNA interference (RNAi) is an intrinsic cellular mechanism for the regulation of gene expression. Harnessing the innate power of this system enables us to knockdown gene expression levels in loss of gene function studies.
There are two main methods for performing RNAi. The first is the use of small interfering RNAs (siRNAs) that are chemically synthesized, and the second utilizes short-hairpin RNAs (shRNAs) encoded within plasmids 1. The latter can be transfected into cells directly or packaged into replication incompetent lentiviral particles. The main advantages of using lentiviral shRNAs is the ease of introduction into a wide variety of cell types, their ability to stably integrate into the genome for long term gene knockdown and selection, and their efficacy in conducting high-throughput loss of function screens. To facilitate this we have created the LentiPlex pooled shRNA library.
The MISSION LentiPlex Human shRNA Pooled Library is a genome-wide lentiviral pool produced using a proprietary process. The library consists of over 75,000 shRNA constructs from the TRC collection targeting 15,000+ human genes 2. Each library is tested for shRNA representation before product release to ensure robust library coverage. The library is provided in a ready-to-use lentiviral format at titers of at least 5 x 108 TU/ml via p24 assay and is pre-divided into ten subpools of approximately 8,000 shRNA constructs each. Amplification and sequencing primers are also provided for downstream target identification.
Previous studies established a synergistic antitumor activity of TRAIL when combined with Paclitaxel in A549 cells, a human lung carcinoma cell line 3, 4. In this study we demonstrate the application of a pooled LentiPlex shRNA library to rapidly conduct a positive selection screen for genes involved in the cytotoxicity of A549 cells when exposed to TRAIL and Paclitaxel. One barrier often encountered with high-throughput screens is the cost and difficulty in deconvolution; we also detail a cost-effective polyclonal approach utilizing traditional sequencing.

Here we use a human LentiPlex pooled library and traditional sequencing methods to identify gene targets promoting cell survival. We demonstrate how to set up and deconvolute a LentiPlex screen and validate the results.

MISSION LentiPlex Pooled shRNA Bibliothek Screening in Säugerzellen

RNA interference (RNAi) is an intrinsic cellular mechanism for the regulation of gene expression. Harnessing the innate power of this system enables us to ...

Quantitative and Automated High-throughput Genome-wide RNAi Screens in C. elegans

RNA interference is a powerful method to understand gene function, especially when conducted at a whole-genome scale and in a quantitative context. In C. elegans, gene function can be knocked down simply and efficiently by feeding worms with bacteria expressing a dsRNA corresponding to a specific gene 1. While the creation of libraries of RNAi clones covering most of the C. elegans genome 2,3 opened the way for true functional genomic studies (see for example 4-7), most established methods are laborious. Moy and colleagues have developed semi-automated protocols that facilitate genome-wide screens 8. The approach relies on microscopic imaging and image analysis. 
	Here we describe an alternative protocol for a high-throughput genome-wide screen, based on robotic handling of bacterial RNAi clones, quantitative analysis using the COPAS Biosort (Union Biometrica (UBI)), and an integrated software: the MBioLIMS (Laboratory Information Management System from Modul-Bio) a technology that provides increased throughput for data management and sample tracking. The method allows screens to be conducted on solid medium plates. This is particularly important for some studies, such as those addressing host-pathogen interactions in C. elegans, since certain microbes do not efficiently infect worms in liquid culture.
	We show how the method can be used to quantify the importance of genes in anti-fungal innate immunity in C. elegans. In this case, the approach relies on the use of a transgenic strain carrying an epidermal infection-inducible fluorescent reporter gene, with GFP under the control of the promoter of the antimicrobial peptide gene nlp 29 and a red fluorescent reporter that is expressed constitutively in the epidermis. The latter provides an internal control for the functional integrity of the epidermis and nonspecific transgene silencing9. When control worms are infected by the fungus they fluoresce green. Knocking down by RNAi a gene required for nlp 29 expression results in diminished fluorescence after infection. Currently, this protocol allows more than 3,000 RNAi clones to be tested and analyzed per week, opening the possibility of screening the entire genome in less than 2 months.

Quantitative and Automated High-throughput Genome-wide RNAi Screens in C. elegans

We describe a protocol using C. elegans and RNAi feeding libraries that allows automated measurement of multiple parameters such as fluorescence, size and opacity of individual worms in a population. We give one example of a screen to identify genes involved in anti-fungal innate immunity in C. elegans.

Quantitative und automatisierte Hochdurchsatz-genomweiten RNAi-Screens in C elegans</em

RNA interference is a powerful method to understand gene function, especially when conducted at a whole-genome scale and in a quantitative context. In C. ...

A Novel Bayesian Change-point Algorithm for Genome-wide Analysis of Diverse ChIPseq Data Types

ChIPseq is a widely used technique for investigating protein-DNA interactions. Read density profiles are generated by using next-sequencing of protein-bound DNA and aligning the short reads to a reference genome. Enriched regions are revealed as peaks, which often differ dramatically in shape, depending on the target protein1. For example, transcription factors often bind in a site- and sequence-specific manner and tend to produce punctate peaks, while histone modifications are more pervasive and are characterized by broad, diffuse islands of enrichment2. Reliably identifying these regions was the focus of our work.
Algorithms for analyzing ChIPseq data have employed various methodologies, from heuristics3-5 to more rigorous statistical models, e.g. Hidden Markov Models (HMMs)6-8. We sought a solution that minimized the necessity for difficult-to-define, ad hoc parameters that often compromise resolution and lessen the intuitive usability of the tool. With respect to HMM-based methods, we aimed to curtail parameter estimation procedures and simple, finite state classifications that are often utilized.
Additionally, conventional ChIPseq data analysis involves categorization of the expected read density profiles as either punctate or diffuse followed by subsequent application of the appropriate tool. We further aimed to replace the need for these two distinct models with a single, more versatile model, which can capably address the entire spectrum of data types.
To meet these objectives, we first constructed a statistical framework that naturally modeled ChIPseq data structures using a cutting edge advance in HMMs9, which utilizes only explicit formulas-an innovation crucial to its performance advantages. More sophisticated then heuristic models, our HMM accommodates infinite hidden states through a Bayesian model. We applied it to identifying reasonable change points in read density, which further define segments of enrichment. Our analysis revealed how our Bayesian Change Point (BCP) algorithm had a reduced computational complexity-evidenced by an abridged run time and memory footprint. The BCP algorithm was successfully applied to both punctate peak and diffuse island identification with robust accuracy and limited user-defined parameters. This illustrated both its versatility and ease of use. Consequently, we believe it can be implemented readily across broad ranges of data types and end users in a manner that is easily compared and contrasted, making it a great tool for ChIPseq data analysis that can aid in collaboration and corroboration between research groups. Here, we demonstrate the application of BCP to existing transcription factor10,11 and epigenetic data12 to illustrate its usefulness.

Our Bayesian Change Point (BCP) algorithm builds on state-of-the-art advances in modeling change-points via Hidden Markov Models and applies them to chromatin immunoprecipitation sequencing (ChIPseq) data analysis. BCP performs well in both broad and punctate data types, but excels in accurately identifying robust, reproducible islands of diffuse histone enrichment.

A Novel Bayesian Change-Punkt Algorithmus für genomweite Analyse Diverse ChIPseq Datentypen

ChIPseq is a widely used technique for investigating protein-DNA interactions. Read density profiles are generated by using next-sequencing of ...

Genome-wide Gene Deletions in Streptococcus sanguinis by High Throughput PCR

Transposon mutagenesis and single-gene deletion are two methods applied in genome-wide gene knockout in bacteria 1,2. Although transposon mutagenesis is less time consuming, less costly, and does not require completed genome information, there are two weaknesses in this method: (1) the possibility of a disparate mutants in the mixed mutant library that counter-selects mutants with decreased competition; and (2) the possibility of partial gene inactivation whereby genes do not entirely lose their function following the insertion of a transposon. Single-gene deletion analysis may compensate for the drawbacks associated with transposon mutagenesis. To improve the efficiency of genome-wide single gene deletion, we attempt to establish a high-throughput technique for genome-wide single gene deletion using Streptococcus sanguinis as a model organism. Each gene deletion construct in S. sanguinis genome is designed to comprise 1-kb upstream of the targeted gene, the aphA-3 gene, encoding kanamycin resistance protein, and 1-kb downstream of the targeted gene. Three sets of primers F1/R1, F2/R2, and F3/R3, respectively, are designed and synthesized in a 96-well plate format for PCR-amplifications of those three components of each deletion construct. Primers R1 and F3 contain 25-bp sequences that are complementary to regions of the aphA-3 gene at their 5' end. A large scale PCR amplification of the aphA-3 gene is performed once for creating all single-gene deletion constructs. The promoter of aphA-3 gene is initially excluded to minimize the potential polar effect of kanamycin cassette. To create the gene deletion constructs, high-throughput PCR amplification and purification are performed in a 96-well plate format. A linear recombinant PCR amplicon for each gene deletion will be made up through four PCR reactions using high-fidelity DNA polymerase. The initial exponential growth phase of S. sanguinis cultured in Todd Hewitt broth supplemented with 2.5% inactivated horse serum is used to increase competence for the transformation of PCR-recombinant constructs. Under this condition, up to 20% of S. sanguinis cells can be transformed using ~50 ng of DNA. Based on this approach, 2,048 mutants with single-gene deletion were ultimately obtained from the 2,270 genes in S. sanguinis excluding four gene ORFs contained entirely within other ORFs in S. sanguinis SK36 and 218 potential essential genes. The technique on creating gene deletion constructs is high throughput and could be easy to use in genome-wide single gene deletions for any transformable bacteria.

Genome-wide Gene Deletions in Streptococcus sanguinis by High Throughput PCR

An efficient genome-wide single gene mutation method has been established using Streptococcus sanguinis as a model organism. This method has achieved via high throughput recombinant PCRs and transformations.

Genomweiten Gen-Deletionen in<em&gt; Streptococcus sanguinis</em&gt; Von High Throughput PCR

Transposon  mutagenesis and single-gene deletion are two methods applied in genome-wide  gene knockout in bacteria 1,2. Although transposon mutagenesis is ...

Polysome Fractionation and Analysis of Mammalian Translatomes on a Genome-wide Scale

mRNA translation plays a central role in the regulation of gene expression and represents the most energy consuming process in mammalian cells. Accordingly, dysregulation of mRNA translation is considered to play a major role in a variety of pathological states including cancer. Ribosomes also host chaperones, which facilitate folding of nascent polypeptides, thereby modulating function and stability of newly synthesized polypeptides. In addition, emerging data indicate that ribosomes serve as a platform for a repertoire of signaling molecules, which are implicated in a variety of post-translational modifications of newly synthesized polypeptides as they emerge from the ribosome, and/or components of translational machinery. Herein, a well-established method of ribosome fractionation using sucrose density gradient centrifugation is described. In conjunction with the in-house developed &#8220;anota&#8221; algorithm this method allows direct determination of differential translation of individual mRNAs on a genome-wide scale. Moreover, this versatile protocol can be used for a variety of biochemical studies aiming to dissect the function of ribosome-associated protein complexes, including those that play a central role in folding and degradation of newly synthesized polypeptides.

Ribosomes play a central role in protein synthesis. Polyribosome (polysome) fractionation by sucrose density gradient centrifugation allows direct determination of translation efficiencies of individual mRNAs on a genome-wide scale. In addition, this method can be used for biochemical analysis of ribosome- and polysome-associated factors such as chaperones and signaling molecules.

Polysomprofile Fraktionierung und Analyse von Säuger Translatomes auf einer Genom-weite Skala

mRNA translation plays a central role in the regulation of gene expression and represents the most energy consuming process in mammalian cells. ...

Detection of miRNA Targets in High-throughput Using the 3'LIFE Assay

Luminescent Identification of Functional Elements in 3&#8217;UTRs (3&#8217;LIFE) allows the rapid identification of targets of specific miRNAs within an array of hundreds of queried 3&#8217;UTRs. Target identification is based on the dual-luciferase assay, which detects binding at the mRNA level by measuring translational output, giving a functional readout of miRNA targeting. 3&#8217;LIFE uses non-proprietary buffers and reagents, and publically available reporter libraries, making genome-wide screens feasible and cost-effective. 3&#8217;LIFE can be performed either in a standard lab setting or scaled up using liquid handling robots and other high-throughput instrumentation. We illustrate the approach using a dataset of human 3&#8217;UTRs cloned in 96-well plates, and two test miRNAs, let-7c and miR-10b. We demonstrate how to perform DNA preparation, transfection, cell culture and luciferase assays in 96-well format, and provide tools for data analysis. In conclusion 3&#39;LIFE is highly reproducible, rapid, systematic, and identifies high confidence targets.

Luminescent identification of functional elements in 3&#8217; untranslated regions (3&#8217;UTRs) (3&#8217;LIFE) is a technique to identify functional regulation in 3&#8217;UTRs by miRNAs or other regulatory factors. This protocol utilizes high-throughput methodology such as 96-well transfection and luciferase assays to screen hundreds of putative interactions for functional repression.

Nachweis von miRNA Targets in Hochdurchsatz-Verwendung des 3&#39;LIFE Assay

Luminescent Identification of Functional Elements in 3&#8217;UTRs (3&#8217;LIFE) allows the rapid identification of targets of specific miRNAs within an ...

Genome-wide Mapping of Drug-DNA Interactions in Cells with COSMIC (Crosslinking of Small Molecules to Isolate Chromatin)

The genome is the target of some of the most effective chemotherapeutics, but most of these drugs lack DNA sequence specificity, which leads to dose-limiting toxicity and many adverse side effects. Targeting the genome with sequence-specific small molecules may enable molecules with increased therapeutic index and fewer off-target effects. N-methylpyrrole/N-methylimidazole polyamides are molecules that can be rationally designed to target specific DNA sequences with exquisite precision. And unlike most natural transcription factors, polyamides can bind to methylated and chromatinized DNA without a loss in affinity. The sequence specificity of polyamides has been extensively studied in vitro with cognate site identification (CSI) and with traditional biochemical and biophysical approaches, but the study of polyamide binding to genomic targets in cells remains elusive. Here we report a method, the crosslinking of small molecules to isolate chromatin (COSMIC), that identifies polyamide binding sites across the genome. COSMIC is similar to chromatin immunoprecipitation (ChIP), but differs in two important ways: (1) a photocrosslinker is employed to enable selective, temporally-controlled capture of polyamide binding events, and (2) the biotin affinity handle is used to purify polyamide&#8211;DNA conjugates under semi-denaturing conditions to decrease DNA that is non-covalently bound. COSMIC is a general strategy that can be used to reveal the genome-wide binding events of polyamides and other genome-targeting chemotherapeutic agents.

Genome-wide Mapping of Drug-DNA Interactions in Cells with COSMIC Crosslinking of Small Molecules to Isolate Chromatin

Identifying the direct targets of genome-targeting molecules remains a major challenge. To understand how DNA-binding molecules engage the genome, we developed a method that relies on crosslinking of small molecules to isolate chromatin (COSMIC).

Genomweite Kartierung der Drug-DNA-Wechselwirkungen in Zellen mit COSMIC (Vernetzung von kleinen Molekülen, um Chromatin isolieren)

The genome is the target of some of the most effective chemotherapeutics, but most of these drugs lack DNA sequence specificity, which leads to ...

Genome-wide Purification of Extrachromosomal Circular DNA from Eukaryotic Cells

Extrachromosomal circular DNAs (eccDNAs) are common genetic elements in Saccharomyces cerevisiae and are reported in other eukaryotes as well. EccDNAs contribute to genetic variation among somatic cells in multicellular organisms and to evolution of unicellular eukaryotes. Sensitive methods for detecting eccDNA are needed to clarify how these elements affect genome stability and how environmental and biological factors&#160;induce their formation in eukaryotic cells. This video presents a sensitive eccDNA-purification method called Circle-Seq. The method encompasses column purification of circular DNA, removal of remaining linear chromosomal DNA, rolling-circle amplification of eccDNA, deep sequencing, and mapping. Extensive exonuclease treatment&#160;was&#160;required for sufficient linear chromosomal DNA degradation. The rolling-circle amplification step by &#966;29 polymerase enriched for circular DNA over linear DNA. Validation of the Circle-Seq method on three S. cerevisiae CEN.PK populations of 1010 cells detected hundreds of eccDNA profiles in sizes larger than 1 kilobase. Repeated findings of ASP3-1, COS111, CUP1, RSC30,&#160;HXT6, HXT7 genes on circular DNA in both S288c and CEN.PK suggests that DNA circularization is conserved between strains at these loci. In sum, the Circle-Seq method has broad applicability for genome-scale screening for eccDNA in eukaryotes as well as for detecting specific eccDNA types.

This paper presents a sensitive method called Circle-Seq for purifying extrachromosomal circular DNA (eccDNA). The method encompasses column purification, removal of remaining linear chromosomal DNA, rolling-circle amplification and high-throughput sequencing. Circle-Seq is applicable to genome-scale screening of eukaryotic eccDNA and studying genome instability and copy-number variation.

Genomweite Reinigung von extrachromosomale zirkuläre DNA aus eukaryotischen Zellen

Extrachromosomal circular DNAs (eccDNAs) are common genetic elements in Saccharomyces cerevisiae and are reported in other eukaryotes as well. EccDNAs ...