The authors have no acknowledgements.

1. Kennzeichnung Reaktion <ol><li> Vor, Pre-Aliquot Cyanin 3 und 5-markierten dUTPs, unmarkierten Nukleotiden und Zufallsprimer an den Hersteller empfohlenen Konzentrationen verwenden in 96-Well-Platten und bei -20 C einsatzbereit. Für die Zwecke dieses Protokolls Aliquot von 10,5 &amp; mgr; l des geeigneten markiertem dUTP und 10,5 ul unmarkierter Nukleotide und Zufallsprimer in jede Vertiefung. </li><li> Auftauen ready-to-use Platte mit 96 Vertiefungen von Nukleotiden und Primern bei 4 ° C für etwa 1 Stunde, vor Licht geschützt. </li><li> Nach dem Auftauen Gleichgewicht dieser Platte bei Raumtemperatur für mindestens 30 Minuten, vor Licht geschützt. </li><li> Äquilibrieren DNA-Proben bei 60 ° C für mindestens 15 min. </li><li> Verwendung einer Flüssigkeit handhabenden Roboters, verzichtet Nuklease-freies Wasser zu jeder Vertiefung einer 96-Well-Platte. HINWEIS: Die Wassermenge hängt von der Konzentration jedes Eingangs DNA-Probe ab und sollte ausreichen, um in einer Endkonzentration von 50 ng / ul führt. </li><li> Verwendung eines flüssigen hanling Roboter-Pipette 1 ug DNA in eine Vertiefung der 96-Well-Platte (siehe 1.5), um das Gesamtvolumen auf 20 ul zu bringen. HINWEIS: Kleinere Mengen von DNA kann verwendet werden, obwohl die Qualität der resultierenden Daten beeinträchtigt sein kann (zum wertvollen Proben können Eingabe DNA Mengen bis 400 ng) verwendet werden. </li><li> Verwendung einer Flüssigkeit handhabenden Roboter, übertragen 20 ul äquilibrierten Nukleotide und Primer in jede Vertiefung der Platte verdünnt DNA. </li><li> Verschließen Sie die Platte mit 96 Vertiefungen mit Verschlussstreifen (a dicht ist entscheidend). </li><li> Die DNA zu denaturieren bei 99 ° C für 10 min in einer PCR-Maschine mit einem beheizten Deckel und rasten kühl auf Eis für 5 min auf Glühen Primer. </li><li> Mit einem Liquid-Handling-Roboter, fügen Sie 10 ul Klenow-Exo-DNA-Polymerase-Enzym zu jedem DNAs und Pipetten Mischung gründlich. HINWEIS: Das Gesamtvolumen sollte 50 ul sein. </li><li> Verschließen Sie die Platte mit 96 Vertiefungen und bei 37 ° C für 16 Stunden. ANMERKUNG: Eine kürzere Inkubationszeit von 4 h reicht jedoch ein O / Ncubation kann bequemer sein. </li><li> Verwendung eines Flüssigkeitshandhabungsroboter, mit 5 ul Stoppuffer zu jedem Well. ANMERKUNG: Eine Zusammenfassung der für die Markierungsreaktion verwendeten Reagenzien ist in Tabelle 1 gezeigt. </li></ol> 2. Entfernung von Nicht eingebaute Nukleotide <ol><li> Entfernen eingebauten Nukleotiden unter Verwendung von Silica-Membran von Spin-Säulen und eine dedizierte Spin-Säule Bearbeitungsroboter (die Spin-Säulen können auch manuell bearbeitet werden). Folgen Sie den Anweisungen des Herstellers. <ol><li> Den Inhalt jeder Vertiefung in ein 2-ml-Tube; Pre-Label diese mit gut-IDs. Anmerkung: Dieser Schritt kann manuell oder vorzugsweise mit Hilfe einer Flüssigkeitshandhabungsroboter durchgeführt werden. </li><li> Bei Verwendung einer Spin-Säule Bearbeitungsroboter, dann laden Sie den Roboter mit 2-ml-Röhrchen, die DNA-Reinigung Spin-Säulen und die damit verbundenen Puffer. </li><li> Nach Eintragen von 250 ul Hochsalz, DNA-Bindungspuffer (Puffer PB) an die Markierungsreaktion, um die markierten DNA an die Kieselsäure bindenMembran. </li><li> Verunreinigungen durch zweimaliges Waschen der Membran mit 500 ul Waschpuffer (Puffer PE). </li><li> Werden 15 ul niedrigen Salz Elutionspuffer (Puffer EB) auf die Membran, um die gereinigte markierte DNA in einem Volumen von ~ 12 &amp; mgr; l zu gewinnen. </li></ol></li></ol> 3. Kombinieren Hyb Paare <ol><li> Kombinieren Sie die entsprechenden Paare von Cyanin 3 und 5-markierte DNA, COT-1-DNA, ein Hersteller gelieferten blockieren-Mix und ein Hersteller gelieferten Hybridisierungspuffer unter Verwendung eines flüssigen Handhabungsroboter. Hinweis: Diese hyb Paare können eine Probe und eine Referenz oder Probe vs Probe, wenn gemeinsamen CNVs sind kein Thema (zB wir routinemäßig zu koppeln Phänotyp-übereinstimmende Muster, wie ein Nierendysplasie Patienten vs einer Kraniosynostose Patienten, da sie sehr sind unwahrscheinlich, dass die gleichen klinisch signifikanten CNV tragen). Bei Verwendung einer Referenz-DNA ist eine kommerzielle DNA Versorgung empfohlen und sollte zusammen mit der Probe verarbeitet werden. <ol><li> Mit ein Liquid-Handling-roBot Fügen COT-1 DNA (3333 ng / ul), die vom Hersteller gelieferten Sperrmischung und Hybridisierungspuffer in jede Vertiefung einer 96-Well-Platte, so dass jede Mulde 1,1 ul Cot-1-DNA, 4,95 &amp; mgr; l Blockierungs Mischung und 24.75 ul Hybridisierungspuffer. </li><li> Hinzufügen 9,35 ul des geeigneten Cyanin 3-markierter DNA in jede Kammer. Vornässen jede Spitze zu verbessern Pipettiergenauigkeit. </li><li> Hinzufügen 9,35 ul des geeigneten Cyanin5 markierten DNA in jede Kammer. Vornässen jede Spitze zu verbessern Pipettiergenauigkeit. </li><li> Verschließen Sie die Platte mit 96 Vertiefungen und Vortex für 1 min. Drehen Sie die Platte mit 96 Vertiefungen, um Inhalte auf den Boden jeder Vertiefung zu sammeln. </li></ol></li></ol> 4. Hybridisierung <ol><li> Heizen Sie eine Hybridisierungsofen auf 65 ° C vorwärmen und eine Trägerschlitten und einer Hybridisierungskammer für jedes Array Objektträger. <ol><li> Denaturieren der markierten DNA in einem vorge Hybridisierungsinkubation bevor Aufbringen auf den Arrays. Führen Sie die Hybridisierung in einem rotierenden Ofen für 24 Stunden. </li><li> Inkubiere die Platte mit 96 Vertiefungen bei 70 ° C für 30 min und dann lassen bei 37 ° C für mindestens 5 min. </li><li> Die Arbeit an einem beheizten Plattform bei 42 ° C, laden jede Sicherung Rutsche in eine Hybridisierungskammer vor der Verwendung. Sicherzustellen, dass der transparente Teil der Dichtung Schieber fluchtet mit dem &quot;gefensterten&quot; Teil des Hybridisierungskammer. </li><li> Pipettieren Sie 42 ul des Hybridisierungsmischung vorbereitete (siehe Abschnitt 3) auf die entsprechende Position auf dem Array sichern Rutsche. Vornässen jede Spitze zu verbessern Pipettiergenauigkeit. Pipette langsam auf die Mitte jeder Position, so dass die Flüssigkeit nicht den Gummiring Grenze berühren. </li><li> Wenn alle Positionen auf dem Trägerschlitten gefüllt sind, lassen Sie das Array Rutsche auf sie und die Hybridisierungskammer zu montieren. Stellen Sie sicher, dass die Seite der Anordnung mit Schreiben auf es mit Blick auf die Unterlage Rutschbahn. Achten Sie darauf, die Hybridisierungskammer Schraube festdrehen. </li><li> Überprüfen Sie die zusammengebauten Hybridisierungskammer. ENSure daß es keine Leckage von Hybridisierungsmischung außerhalb der Gummiring Grenzen und jede Luftblase ~ 4 mm in der Höhe, wenn die Hybridisierungskammer ist an seinem Ende senkrecht ruhte. Drehen Sie die Hybridisierungskammer und überprüfen, dass sich keine Luftblasen, die in Position und bewegt sich nicht stecken. Wenn es irgendwelche von ihnen, geben dem Raum einen starken Schlag auf die Bank. Überprüfen Sie, ob alle Luftblasen in Bewegung sind. </li><li> Platzieren Sie die Hybridisierungskammer in den rotierenden Ofen bei 65 ° C für 24 Stunden. Sicherstellen, dass der Ofen Rotor ist ausgewogen; verwenden andere leere Kammern, falls erforderlich. </li></ol></li></ol> 5. Waschen und Scannen von Dias <ol><li> Waschen Sie Arrays, um überschüssige markierte DNA zu entfernen und dann scannen, um Fluoreszenz jeder Probe zu messen. <ol><li> Nehmen Hybridisierungskammern aus dem Ofen und zu demontieren. Die Array-und Dichtungsfolien werden miteinander verklebt werden; tauchen diese in Waschpuffer 1 und mit einem Paar aus Kunststoff, Flachzange eingefasst, sie auseinander zu hebeln. </li><li> Discard die Dichtung Rutsche und legen Sie das Array Rutsche in ein Rack in Puffer 1 getaucht. </li><li> Waschen Sie die Array-Folie in ~ 700 ml frischem Waschpuffer 1 für 5 Minuten, unter starkem Rühren (mit einem Floh und Magnetrührer). </li><li> Übertragen Sie die Array-Folie, um ~ 700 ml Waschpuffer 2 und waschen für 90 sec, unter kräftigem Rühren. Gently heben Sie die Array gleitet aus Waschpuffer 2, sollten sie trocken entstehen. </li><li> Laden Sie das Array Abgleiten in einen Objektträgerhalter aus dem Scanner, über einen Schiebeschutz. Legen Sie die Folie in das Array-Scanner und scannen folgenden des Arrays Herstellers. </li></ol></li></ol>

<ol>
	<li>Miller, D. T., 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=Consensus+statement:+chromosomal+microarray+is+a+first-tier+clinical+diagnostic+test+for+individuals+with+developmental+disabilities+or+congenital+anomalies.">Consensus statement: chromosomal microarray is a first-tier clinical diagnostic test for individuals with developmental disabilities or congenital anomalies.</a> Am. J. Hum. Genet. 86, 749-764 (2010).</li><li>Ahn, J. W., 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=Array+CGH+as+a+first+line+diagnostic+test+in+place+of+karyotyping+for+postnatal+referrals+-+results+from+four+years'+clinical+application+for+over+8,700+patients.">Array CGH as a first line diagnostic test in place of karyotyping for postnatal referrals - results from four years' clinical application for over 8,700 patients.</a> Mol. Cytogenet. 6 (16), 1755-8166 (2013).</li><li>Ahn, J. W., 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=Validation+and+implementation+of+array+comparative+genomic+hybridisation+as+a+first+line+test+in+place+of+postnatal+karyotyping+for+genome+imbalance.">Validation and implementation of array comparative genomic hybridisation as a first line test in place of postnatal karyotyping for genome imbalance.</a> Mol. Cytogenet. 3 (9), 1755-8166 (2010).</li><li>Beaudet, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+utility+of+chromosomal+microarray+analysis+in+developmental+and+behavioral+pediatrics.">The utility of chromosomal microarray analysis in developmental and behavioral pediatrics.</a> Child Dev. 84, 121-132 (2013).</li><li>Park, S. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+implementation+of+whole-genome+array+CGH+as+a+first-tier+test+in+5080+pre+and+postnatal+cases.">Clinical implementation of whole-genome array CGH as a first-tier test in 5080 pre and postnatal cases.</a> Mol. Cytogenet. 4, 12 (2011).</li><li>Iafrate, A. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+large-scale+variation+in+the+human+genome.">Detection of large-scale variation in the human genome.</a> Nat. Genet. 36, 949-951 (2004).</li><li>Redon, 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=Global+variation+in+copy+number+in+the+human+genome.">Global variation in copy number in the human genome.</a> Nature. 444, 444-454 (2006).</li><li>Cafferkey, M., Ahn, J. W., Flinter, F., Ogilvie, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phenotypic+features+in+patients+with+15q11.2(BP1-BP2)+deletion:+Further+delineation+of+an+emerging+syndrome.">Phenotypic features in patients with 15q11.2(BP1-BP2) deletion: Further delineation of an emerging syndrome.</a> Am. J. Med. Genet. A. 164, 1916-1922 (2014).</li><li>Molin, A. 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=A+novel+microdeletion+syndrome+at+3q13.31+characterised+by+developmental+delay,+postnatal+overgrowth,+hypoplastic+male+genitals,+and+characteristic+facial+features.">A novel microdeletion syndrome at 3q13.31 characterised by developmental delay, postnatal overgrowth, hypoplastic male genitals, and characteristic facial features.</a> J. Med. Genet. 49, 104-109 (2012).</li><li>Tropeano, 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=Male-biased+autosomal+effect+of+16p13.11+copy+number+variation+in+neurodevelopmental+disorders.">Male-biased autosomal effect of 16p13.11 copy number variation in neurodevelopmental disorders.</a> PLoS One. 8, e61365 (2013).</li><li>Bon, B. W., 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=Further+delineation+of+the+15q13+microdeletion+and+duplication+syndromes:+a+clinical+spectrum+varying+from+non-pathogenic+to+a+severe+outcome.">Further delineation of the 15q13 microdeletion and duplication syndromes: a clinical spectrum varying from non-pathogenic to a severe outcome.</a> J. Med. Genet. 46, 511-523 (2009).</li></ol>

The authors have nothing to disclose.

Array-CGH wird ausgewogenen Umlagerungen oder Ploidie Anomalien wie Triploidie nicht erkennen. Ferner können geringe mosaic Ungleichgewichte nicht erkannt werden. Hat Array-CGH jedoch eine höhere Auflösung für CNV Erkennung als G-gebändert Chromosomenanalyse, die es in vielen Labors Zytogenetik ersetzt hat. Es ist daher der derzeitige Goldstandard für die genomweite CNV-Erkennung. Sie kann von der nächsten Generation Sequenziertechnologien in der Zukunft ersetzt werden, aber derzeit, ihre Kosten und die technisch...

Es ist seit vielen Jahren, dass Deletionen oder zusätzliche Kopien von Chromosomensegmente verursachen geistiger Behinderung, Dysmorphien und congentical Fehlbildungen bekannt, und in einigen Fällen dazu führen, genetische Syndrome 1. Doch die einzige Technologie zur Verfügung, bis Mitte der 2000er Jahre für die genomweite Erfassung dieser Veränderungen war, G-gebändert Chromosomenanalyse, die eine Auflösung von rund 5-10MB hat, je nach Region und Art des Ungleichgewichts und welche nicht abnorme Chromosomen, wo Material wurde von einer Region aus einem anderen Chromosom mit der gleichen Bandenmuster ersetzt. Neben zytogenetischen Techniken wie Fluoreszenz in situ Hybridisierung und Multiplex Ligation-spezifischen Sonde Verstärkung wurden für die Abfrage bestimmter Loci vorhanden, bei Verdacht auf bestimmte syndromale Ungleichgewicht, aber es war nicht bis zur Einführung der Array Comparative Genomic Hybridization (Array-CGH) in der klinischen Routinediagnose service 2-5, die genomweite Erfassung der Kopienzahl-Varianten (CNVs) wurde zu einem stark erhöhten Auflösung (typischerweise um 120kb) möglich. Klinische Servicearbeiten neben Studien haben gezeigt, dass CNVs für einige Regionen in der Normalbevölkerung 6-7 weit verbreitet, während andere CNVs, die zuvor nicht nachweisbar, werden mit neurodisabilities wie Autismus und Epilepsie 8-11 verbunden. Die in diesem Dokument beschriebenen Protokoll wird in unserem UK National Health Service (NHS) klinisch-diagnostischen Labor; wir neuartige Hybridisierung Strategien, Chargenprüfung und Robotik zu Kosten in diesem staatlich finanzierten Dienst minimieren. Vor dem unten beschriebenen Protokoll sollte hochwertige DNA aus dem entsprechenden Ausgangsmaterial, meist Blut, kultivierten Zellen oder Gewebeproben entnommen werden. Spektrophotometrie verwendet werden, um Konzentration zu messen (sollte&gt; 50 ng / ul) und prüfen 260: 280 Absorptionsverhältnisse (zu be von 1,8 bis 2,0). Die Gelelektrophorese kann kontrolliert werden, dass die DNA mit hohem Molekulargewicht ohne signifikanten Abbau werden. Dieses Protokoll wird für einen höheren Durchsatz Laboratorien, Kennzeichnung 96 Proben pro Lauf mit automatisierten Liquid-Handling-Robotik sollen. Es kann jedoch für niedrigere Durch Labors ohne Automatisierung angepaßt werden.

<table border="0" cellpadding="0" cellspacing="0" width="573">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Name of Material/ Equipment</td>
			<td style="width:71px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:167px;">Comments/Description</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">CGH microarray 8 x 60K</td>
			<td style="width:71px;">Agilent</td>
			<td style="width:119px;">G4126</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Array CGH wash buffers</td>
			<td style="width:71px;">Agilent</td>
			<td style="width:119px;">5188-5226</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Array CGH hybridisation buffer</td>
			<td style="width:71px;">Agilent</td>
			<td style="width:119px;">5188-5380</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Minelute purification kit</td>
			<td style="width:71px;">Qiagen</td>
			<td align="right" style="width:119px;">28006</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Array CGH labelling kit</td>
			<td style="width:71px;">Enzo</td>
			<td style="width:119px;">ENZ-42672-0000</td>
			<td></td>
		</tr>
	</tbody>
</table>

array comparative genomic hybridization (array cgh) for detection of genomic copy number variants

Array CGH for the detection of genomic copy number variants has replaced G-banded karyotype analysis. This paper describes the technology and its application in a clinical diagnostic service laboratory. DNA extracted from a patient&#8217;s sample (blood, saliva or other tissue types) is labeled with a fluorochrome (either cyanine 5 or cyanine 3). A reference DNA sample is labeled with the opposite fluorochrome. There follows a cleanup step to remove unincorporated nucleotides before the labeled DNAs are mixed and resuspended in a hybridization buffer and applied to an array comprising ~60,000 oligonucleotide probes from loci across the genome, with high probe density in clinically important areas. Following hybridization, the arrays are washed, then scanned and the resulting images are analyzed to measure the red and green fluorescence for each probe. Software is used to assess the quality of each probe measurement, calculate the ratio of red to green fluorescence and detect potential copy number variants.

Jede Sonde auf einem Array hybridisiert wird als eine Mischung aus roten und grünen Fluorochrome visualisiert (siehe Abbildung 1). Das Verhältnis von rot nach grün fluoreszierenden Signals für jede Sonde wird vom Scanner quantifiziert und die zugehörige Software zeichnet diese als log2 Verhältnisse entsprechend ihrer genomischen Position und identifiziert Bereiche, die außerhalb voreingestellten Grenzen. Die resultierende Array Spuren ermöglichen Interpretation der Regionen als genomisch unsymme...

Watch this Scientific Journal Video about Array Comparative Genomic Hybridization Array CGH for Detection of Genomic Copy Number Variants at JoVE.com

Array Comparative Genomic Hybridization Array CGH for Detection of Genomic Copy Number Variants

Array-CGH für den Nachweis von genomischer Kopienzahl-Varianten hat G-gebändert Karyotypanalyse ersetzt. Dieses Papier beschreibt die Technologie und ihre Anwendung in einem Diagnose-Service-Labor.

Array Comparative Genomic Hybridization (Array-CGH) zum Nachweis von Genomic Copy Number Varianten

Array CGH for the detection of genomic copy number variants has replaced G-banded karyotype analysis. This paper describes the technology and its ...

array-comparative-genomic-hybridization-array-cgh-for-detection

Research

JoVE Journal

Biology

Array Comparative Genomic Hybridization (Array CGH) for Detection of Genomic Copy Number Variants

19.4K Aufrufe.  Guy's & St Thomas' NHS Foundation Trust.  Array-CGH für den Nachweis von genomischer Kopienzahl-Varianten hat G-gebändert Karyotypanalyse ersetzt. Dieses Papier beschreibt die Technologie und ihre Anwendung in einem Diagnose-Service-Labor. 

Serie: Array Comparative Genomic Hybridization Array CGH for Detection of Genomic Copy Number Variants

Isolation of Genomic DNA from Mouse Tails

Isolierung genomischer DNA aus Maus-Tails

Forschung

Biologie

Technical Demonstration of Whole Genome Array Comparative Genomic Hybridization

Array comparative genomic hybridization (array CGH) is a method for detecting gains and losses of DNA segments or gene dosage in the genome 1. Recent advances in this technology have enabled high resolution comparison of whole genomes for the identification of genetic alterations in cancer and other genetic diseases 2. The Sub-Megabase Resolution Tiling-set array (or SMRT) array is comprised of a set of approximately thirty thousand overlapping bacterial artificial chromosome (BAC) clones that span the human genome in ~100 kilobase pair (kb) segments 2. These BAC targets are individually synthesized and spotted in duplicate on a single glass slide 2-4. Array CGH is based on the principle of competitive hybridization. Sample and reference DNA are differentially labeled with Cyanine-3 and Cyanine-5 fluorescent dyes, and co-hybridized to the array. After an incubation period the unbound samples are washed from the slide and the array is imaged. A freely available custom software package called SeeGH (www.flintbox.ca) is used to process the large volume of data collected - a single experiment generates 53,892 data points. SeeGH visualizes the log2 signal intensity ratio between the 2 samples at each BAC target which is vertically aligned with chromosomal position 5,6. The SMRT array can detect alterations as small as 50 kb in size 7. The SMRT array can detect a variety of DNA rearrangement events including DNA gains, losses, amplifications and homozygous deletions. A unique advantage of the SMRT array is that one can use DNA isolated from formalin fixed paraffin embedded samples. When combined with the low input requirements of unamplified DNA (25-100ng) this allows profiling of precious samples such as those produced by microdissection 7,8. This is attributed to the large size of each BAC hybridization target that allows the binding of sufficient labeled samples to produce signals for detection. Another advantage of this platform is the tolerance of tissue heterogeneity, decreasing the need for tedious tissue microdissection 8. This video protocol is a step-by-step tutorial from labeling the input DNA through to signal acquisition for the whole genome tiling path SMRT array.

This video is a technical demonstration of the hybridization protocol for whole genome tiling path array CGH, which scans the entire human genome using only 25-100 ng of DNA that can be isolated from a variety of sources, including archival formalin fixed material.

Technische Demonstration von Whole Genome Array Comparative Genomic Hybridization

Array comparative genomic hybridization (array CGH) is a method for detecting gains and losses of DNA segments or gene dosage in the genome 1.  Recent ...

Micro-drive Array for Chronic in vivo Recording: Drive Fabrication

Chronic recording of large populations of neurons is a valuable technique for studying the function of neuronal circuits in awake behaving rats. Lightweight recording devices carrying a high density array of tetrodes allow for the simultaneous monitoring of the activity of tens to hundreds of individual neurons. Here we describe a protocol for the fabrication of a micro-drive array with twenty one independently movable micro-drives. This device has been used successfully to record from hippocampal and cortical neurons in our lab. We show how to prepare a custom designed, 3-D printed plastic base that will hold the micro-drives. We demonstrate how to construct the individual micro-drives and how to assemble the complete micro-drive array. Further preparation of the drive array for surgical implantation, such as the fabrication of tetrodes, loading of tetrodes into the drive array and gold-plating, is covered in a subsequent video article.

Micro-drive Array for Chronic in vivo Recording: Drive Fabrication

In this protocol we demonstrate how to fabricate a micro-drive array for chronic electrophysiological recordings in rats.

Micro-Drive-Array für chronische In vivo Recording: Drive Fabrication

Chronic recording of large populations of neurons is a valuable technique for studying the function of neuronal circuits in awake behaving rats. ...

Large Insert Environmental Genomic Library Production

The vast majority of microbes in nature currently remain inaccessible to traditional cultivation methods. Over the past decade, culture-independent environmental genomic (i.e. metagenomic) approaches have emerged, enabling researchers to bridge this cultivation gap by capturing the genetic content of indigenous microbial communities directly from the environment. To this end, genomic DNA libraries are constructed using standard albeit artful laboratory cloning techniques. Here we describe the construction of a large insert environmental genomic fosmid library with DNA derived from the vertical depth continuum of a seasonally hypoxic fjord. This protocol is directly linked to a series of connected protocols including coastal marine water sampling [1], large volume filtration of microbial biomass [2] and a DNA extraction and purification protocol [3]. At the outset, high quality genomic DNA is end-repaired with the creation of 5 -phosphorylated blunt ends. End-repaired DNA is subjected to pulsed-field gel electrophoresis (PFGE) for size selection and gel extraction is performed to recover DNA fragments between 30 and 60 thousand base pairs (Kb) in length. Size selected DNA is purified away from the PFGE gel matrix and ligated to the phosphatase-treated blunt-end fosmid CopyControl vector pCC1 (EPICENTRE <a href="http://www.epibio.com/item.asp?ID=385">http://www.epibio.com/item.asp?ID=385</a>). Linear concatemers of pCC1 and insert DNA are subsequently headfull packaged into phage particles by lambda terminase, with subsequent infection of phage-resistant E. coli cells. Successfully transduced clones are recovered on LB agar plates under antibiotic selection and archived in 384-well plate format using an automated colony picking robot (Qpix2, GENETIX). The current protocol draws from various sources including the CopyControl Fosmid Library Production Kit from EPICENTRE and the published works of multiple research groups [4-7]. Each step is presented with best practice in mind. Whenever possible we highlight subtleties in execution to improve overall quality and efficiency of library production. The whole process of fosmid library production and automated colony picking takes at least 7-10 days as there are many incubation steps included. However, there are several stopping points possible which are mentioned within the protocol.

Construction of a fosmid library with environmental genomic DNA isolated from the vertical depth continuum of a seasonally hypoxic fjord is described. The resulting clone library is picked into 384-well plates and archived for downstream sequencing and functional screening by the application of an automated colony picking system.

Large Insert Environmental Genomic Bibliothek Produktion

The vast majority of microbes in nature currently remain inaccessible to traditional cultivation methods. Over the past decade, culture-independent ...

DNA Microarrays: Sample Quality Control, Array Hybridization and Scanning

Microarray expression profiling of the nervous system provides a powerful approach to identifying gene activities in different stages of development, different physiological or pathological states, response to therapy, and, in general, any condition that is being experimentally tested1. Expression profiling of neural tissues requires isolation of high quality RNA, amplification of the isolated RNA and hybridization to DNA microarrays. In this article we describe protocols for reproducible microarray experiments from brain tumor tissue2. We will start by performing a quality control analysis of isolated RNA samples with Agilent's 2100 Bioanalyzer "lab-on-a-chip" technology. High quality RNA samples are critical for the success of any microarray experiment, and the 2100 Bioanalyzer provides a quick, quantitative measurement of the sample quality. RNA samples are then amplified and labeled by performing reverse transcription to obtain cDNA, followed by in vitro transcription in the presence of labeled nucleotides to produce labeled cRNA. By using a dual-color labeling kit, we will label our experimental sample with Cy3 and a reference sample with Cy5. Both samples will then be combined and hybridized to Agilent's 4x44 K arrays. Dual-color arrays offer the advantage of a direct comparison between two RNA samples, thereby increasing the accuracy of the measurements, in particular for small changes in expression levels, because the two RNA samples are hybridized competitively to a single microarray. The arrays will be scanned at the two corresponding wavelengths, and the ratio of Cy3 to Cy5 signal for each feature will be used as a direct measurement of the relative abundance of the corresponding mRNA. This analysis identifies genes that are differentially expressed in response to the experimental conditions being tested.

We demonstrate the use of DNA microarrays for expression profiling of the nervous system. We describe RNA quality control, sample labeling, and array hybridization and scanning.

DNA Microarrays: Sample Quality Control, Array Hybridisierung und Scannen

Microarray expression profiling of the nervous system provides a powerful approach to identifying gene activities in different stages of development, ...

Genomic MRI - a Public Resource for Studying Sequence Patterns within Genomic DNA

Non-coding genomic regions in complex eukaryotes, including intergenic areas, introns, and untranslated segments of exons, are profoundly non-random in their nucleotide composition and consist of a complex mosaic of sequence patterns. These patterns include so-called Mid-Range Inhomogeneity (MRI) regions -- sequences 30-10000 nucleotides in length that are enriched by a particular base or combination of bases (e.g. (G+T)-rich, purine-rich, etc.). MRI regions are associated with unusual (non-B-form) DNA structures that are often involved in regulation of gene expression, recombination, and other genetic processes (Fedorova &amp; Fedorov 2010). The existence of a strong fixation bias within MRI regions against mutations that tend to reduce their sequence inhomogeneity additionally supports the functionality and importance of these genomic sequences (Prakash et al. 2009).
Here we demonstrate a freely available Internet resource -- the Genomic MRI program package -- designed for computational analysis of genomic sequences in order to find and characterize various MRI patterns within them (Bechtel et al. 2008). This package also allows generation of randomized sequences with various properties and level of correspondence to the natural input DNA sequences. The main goal of this resource is to facilitate examination of vast regions of non-coding DNA that are still scarcely investigated and await thorough exploration and recognition.

We present a public computational web site for the analysis of genomic sequences. It detects DNA sequence patterns with various non-random nucleotide compositions. This resource also generates randomized sequences with diverse levels of complexity.

Genomic MRI - eine öffentliche Ressource für ein Studium Sequence Patterns in genomischer DNA

Non-coding genomic regions in complex eukaryotes, including intergenic areas, introns, and untranslated segments of exons, are profoundly non-random in ...

Competitive Genomic Screens of Barcoded Yeast Libraries

By virtue of advances in next generation sequencing technologies, we have access to new genome sequences almost daily. The tempo of these advances is accelerating, promising greater depth and breadth. In light of these extraordinary advances, the need for fast, parallel methods to define gene function becomes ever more important. Collections of genome-wide deletion mutants in yeasts and E. coli have served as workhorses for functional characterization of gene function, but this approach is not scalable, current gene-deletion approaches require each of the thousands of genes that comprise a genome to be deleted and verified. Only after this work is complete can we pursue high-throughput phenotyping. Over the past decade, our laboratory has refined a portfolio of competitive, miniaturized, high-throughput genome-wide assays that can be performed in parallel. This parallelization is possible because of the inclusion of DNA 'tags', or 'barcodes,' into each mutant, with the barcode serving as a proxy for the mutation and one can measure the barcode abundance to assess mutant fitness. In this study, we seek to fill the gap between DNA sequence and barcoded mutant collections. To accomplish this we introduce a combined transposon disruption-barcoding approach that opens up parallel barcode assays to newly sequenced, but poorly characterized microbes. To illustrate this approach we present a new Candida albicans barcoded disruption collection and describe how both microarray-based and next generation sequencing-based platforms can be used to collect 10,000 - 1,000,000 gene-gene and drug-gene interactions in a single experiment.

We have developed comprehensive, unbiased genome-wide screens to understand gene-drug and gene-environment interactions. Methods for screening these mutant collections are presented.

Competitive Genomic Screens von Barcoded Hefe Bibliotheken

By virtue of advances in next generation sequencing technologies, we have access to new genome sequences almost daily.  The tempo of these advances is ...

Detection of Rare Genomic Variants from Pooled Sequencing Using SPLINTER

As DNA sequencing technology has markedly advanced in recent years2, it has become increasingly evident that the amount of genetic variation between any two individuals is greater than previously thought3. In contrast, array-based genotyping has failed to identify a significant contribution of common sequence variants to the phenotypic variability of common disease4,5. Taken together, these observations have led to the evolution of the Common Disease / Rare Variant hypothesis suggesting that the majority of the "missing heritability" in common and complex phenotypes is instead due to an individual's personal profile of rare or private DNA variants6-8. However, characterizing how rare variation impacts complex phenotypes requires the analysis of many affected individuals at many genomic loci, and is ideally compared to a similar survey in an unaffected cohort. Despite the sequencing power offered by today's platforms, a population-based survey of many genomic loci and the subsequent computational analysis required remains prohibitive for many investigators.
To address this need, we have developed a pooled sequencing approach1,9 and a novel software package1 for highly accurate rare variant detection from the resulting data. The ability to pool genomes from entire populations of affected individuals and survey the degree of genetic variation at multiple targeted regions in a single sequencing library provides excellent cost and time savings to traditional single-sample sequencing methodology. With a mean sequencing coverage per allele of 25-fold, our custom algorithm, SPLINTER, uses an internal variant calling control strategy to call insertions, deletions and substitutions up to four base pairs in length with high sensitivity and specificity from pools of up to 1 mutant allele in 500 individuals. Here we describe the method for preparing the pooled sequencing library followed by step-by-step instructions on how to use the SPLINTER package for pooled sequencing analysis (<a href="http://www.ibridgenetwork.org/wustl/splinter" target="_blank">http://www.ibridgenetwork.org/wustl/splinter</a>). We show a comparison between pooled sequencing of 947 individuals, all of whom also underwent genome-wide array, at over 20kb of sequencing per person. Concordance between genotyping of tagged and novel variants called in the pooled sample were excellent. This method can be easily scaled up to any number of genomic loci and any number of individuals. By incorporating the internal positive and negative amplicon controls at ratios that mimic the population under study, the algorithm can be calibrated for optimal performance. This strategy can also be modified for use with hybridization capture or individual-specific barcodes and can be applied to the sequencing of naturally heterogeneous samples, such as tumor DNA.

Pooled DNA sequencing is a fast and cost-effective strategy to detect rare variants associated with complex phenotypes in large cohorts. Here we describe the computational analysis of pooled, next-generation sequencing of 32 cancer-related genes using the SPLINTER software package. This method is scalable, and applicable to any phenotype of interest.

Nachweis seltener Varianten von Genomic Pooled-Sequenzierung mit SPLINTER

As DNA sequencing technology has markedly advanced in recent years2, it has become increasingly evident that the amount of genetic variation between any ...

Genomic Transformation of the Picoeukaryote Ostreococcus tauri

Common problems hindering rapid progress in Plant Sciences include cellular, tissue and whole organism complexity, and notably the high level of genomic redundancy affecting simple genetics in higher plants. The novel model organism Ostreococcus tauri is the smallest free-living eukaryote known to date, and possesses a greatly reduced genome size and cellular complexity1,2, manifested by the presence of just one of most organelles (mitochondrion, chloroplast, golgi stack) per cell, and a genome containing only ~8000 genes. Furthermore, the combination of unicellularity and easy culture provides a platform amenable to chemical biology approaches. Recently, Ostreococcus has been successfully employed to study basic mechanisms underlying circadian timekeeping3-6. Results from this model organism have impacted not only plant science, but also mammalian biology7. This example highlights how rapid experimentation in a simple eukaryote from the green lineage can accelerate research in more complex organisms by generating testable hypotheses using methods technically feasible only in this background of reduced complexity. Knowledge of a genome and the possibility to modify genes are essential tools in any model species. Genomic1, Transcriptomic8, and Proteomic9 information for this species is freely available, whereas the previously reported methods6,10 to genetically transform Ostreococcus are known to few laboratories worldwide.
In this article, the experimental methods to genetically transform this novel model organism with an overexpression construct by means of electroporation are outlined in detail, as well as the method of inclusion of transformed cells in low percentage agarose to allow selection of transformed lines originating from a single transformed cell. Following the successful application of Ostreococcus to circadian research, growing interest in Ostreococcus can be expected from diverse research areas within and outside plant sciences, including biotechnological areas. Researchers from a broad range of biological and medical sciences that work on conserved biochemical pathways may consider pursuing research in Ostreococcus, free from the genomic and organismal complexity of larger model species.

Genomic Transformation of the Picoeukaryote Ostreococcus tauri

This article describes genetic transformation of the unicellular marine alga Ostreococcus tauri by electroporation. This eukaryotic organism is an effective model platform for higher plants, possesing greatly reduced genomic and cellular complexity and being readily amenable to both cell culture and chemical biology.

Genomic Transformation des Picoeukaryote<em&gt; Ostreococcus tauri</em

Common problems hindering rapid progress in Plant Sciences include cellular, tissue and whole organism complexity, and notably the high level of genomic ...

Selective Capture of 5-hydroxymethylcytosine from Genomic DNA

5-methylcytosine (5-mC) constitutes ~2-8% of the total cytosines in human genomic DNA and impacts a broad range of biological functions, including gene expression, maintenance of genome integrity, parental imprinting, X-chromosome inactivation, regulation of development, aging, and cancer1. Recently, the presence of an oxidized 5-mC, 5-hydroxymethylcytosine (5-hmC), was discovered in mammalian cells, in particular in embryonic stem (ES) cells and neuronal cells2-4. 5-hmC is generated by oxidation of 5-mC catalyzed by TET family iron (II)/&alpha;-ketoglutarate-dependent dioxygenases2, 3. 5-hmC is proposed to be involved in the maintenance of embryonic stem (mES) cell, normal hematopoiesis and malignancies, and zygote development2, 5-10. To better understand the function of 5-hmC, a reliable and straightforward sequencing system is essential. Traditional bisulfite sequencing cannot distinguish 5-hmC from 5-mC11. To unravel the biology of 5-hmC, we have developed a highly efficient and selective chemical approach to label and capture 5-hmC, taking advantage of a bacteriophage enzyme that adds a glucose moiety to 5-hmC specifically12.
Here we describe a straightforward two-step procedure for selective chemical labeling of 5-hmC. In the first labeling step, 5-hmC in genomic DNA is labeled with a 6-azide-glucose catalyzed by &beta;-GT, a glucosyltransferase from T4 bacteriophage, in a way that transfers the 6-azide-glucose to 5-hmC from the modified cofactor, UDP-6-N3-Glc (6-N3UDPG). In the second step, biotinylation, a disulfide biotin linker is attached to the azide group by click chemistry. Both steps are highly specific and efficient, leading to complete labeling regardless of the abundance of 5-hmC in genomic regions and giving extremely low background. Following biotinylation of 5-hmC, the 5-hmC-containing DNA fragments are then selectively captured using streptavidin beads in a density-independent manner. The resulting 5-hmC-enriched DNA fragments could be used for downstream analyses, including next-generation sequencing.
Our selective labeling and capture protocol confers high sensitivity, applicable to any source of genomic DNA with variable/diverse 5-hmC abundances. Although the main purpose of this protocol is its downstream application (i.e., next-generation sequencing to map out the 5-hmC distribution in genome), it is compatible with single-molecule, real-time SMRT (DNA) sequencing, which is capable of delivering single-base resolution sequencing of 5-hmC.

Described is a two-step labeling process using &beta;-glucosyltransferase (&beta;-GT) to transfer an azide-glucose to 5-hmC, followed by click chemistry to transfer a biotin linker for easy and density-independent enrichment. This efficient and specific labeling method enables enrichment of 5-hmC with extremely low background and high-throughput epigenomic mapping via next-generation sequencing.

Selektive Aufnahme von 5-Hydroxymethylcytosin aus genomischer DNA

5-methylcytosine (5-mC) constitutes ~2-8% of the total cytosines in human genomic DNA and impacts a broad range of biological functions, including gene ...