The authors have no acknowledgements.

1. L&#39;etichettatura di reazione <ol><li> Prima dell&#39;uso, dUTPs pre-un&#39;aliquota cianinico 3 e 5-etichettati, nucleotidi senza etichetta e primer casuali alle concentrazioni consigliate dal produttore in lastre e negozio a 96 pozzetti a -20 C pronto per l&#39;uso. Ai fini del presente protocollo, aliquota 10,5 ml di adeguata dUTP etichettato e 10,5 ml nucleotidi senza etichetta e primer casuali in ogni pozzetto. </li><li> Scongelare il piatto pronto all&#39;uso 96 pozzetti di nucleotidi e primer a 4 ° C per circa 1 ora, al riparo dalla luce. </li><li> Una volta scongelato, equilibrare questo piatto a temperatura ambiente per almeno 30 minuti, al riparo dalla luce. </li><li> Equilibrare campioni di DNA a 60 ° C per almeno 15 min. </li><li> Utilizzando un robot liquido movimentazione, erogare acqua priva di nucleasi a ciascun pozzetto di una piastra a 96 pozzetti. NOTA: Il volume di acqua dipenderà dalla concentrazione di ciascun campione di DNA input e dovrebbe essere sufficiente a determinare una concentrazione finale di 50 ng / ul. </li><li> Utilizzando un han liquidorobot dling, pipetta 1 mg di DNA in un pozzo della piastra a 96 pozzetti (vedi 1.5) per portare il volume totale a 20 l. NOTA: Piccole quantità di DNA possono essere utilizzati anche se la qualità dei dati risultante può essere compromessa (per i campioni preziosi, le quantità di DNA di ingresso fino a 400 ng possono essere utilizzati). </li><li> Utilizzando un robot manipolatore liquida, trasferire 20 ml di nucleotidi equilibrate e primer in ciascun pozzetto della piastra di DNA diluito. </li><li> Sigillare la piastra a 96 pozzetti con tappi striscia (una tenuta stagna è fondamentale). </li><li> Denaturare il DNA a 99 ° C per 10 min in una macchina PCR con un coperchio riscaldato e quindi far scattare raffreddare su ghiaccio per 5 min a primer ricottura. </li><li> Utilizzando una gestione robot liquido, aggiungere 10 ml di Klenow DNA polimerasi Exo enzima per ogni DNA e mix pipetta accuratamente. NOTA: Il volume totale dovrebbe essere di 50 ml. </li><li> Sigillare la piastra a 96 pozzetti e incubare a 37 ° C per 16 ore. NOTA: A incubazione più breve di 4 ore è sufficiente tuttavia un O / N incubation può essere più conveniente. </li><li> Utilizzando un robot liquido movimentazione, aggiungere 5 ml di tampone di arresto a ciascun pozzetto. NOTA: Una sintesi dei reagenti utilizzati per la reazione di marcatura è mostrato in Tabella 1. </li></ol> 2. Rimozione di Unincorporated nucleotidi <ol><li> Rimuovere nucleotidi non incorporati utilizzando silice membrana a base colonne di spin e un robot di spin elaborazione colonna dedicato (le colonne di rotazione possono essere trattati manualmente). Seguire le istruzioni del produttore. <ol><li> Trasferire il contenuto di ciascun pozzetto in una provetta 2 ml; pre-label questi con ID e di. NOTA: Questa fase può essere eseguita manualmente o, preferibilmente usando un robot di manipolazione di liquido. </li><li> Se si utilizza un trattamento robot Spin Column, quindi caricare il robot con 2 ml tubi, colonne di rotazione di purificazione del DNA e buffer associati. </li><li> Aggiungere 250 microlitri di sale, di legame al DNA tampone (buffer PB) per la reazione di marcatura di legare il DNA marcato per la silicemembrana. </li><li> Rimuovere le impurità lavando membrana due volte con 500 microlitri tampone di lavaggio (tampone PE). </li><li> Aggiungere 15 microlitri tampone di eluizione basso sale (tampone EB) alla membrana per recuperare il purificato, DNA marcato in un volume di ~ 12 microlitri. </li></ol></li></ol> 3. Unire Hyb Pairs <ol><li> Unire le coppie appropriate di cianinico 3 e 5 DNA marcato, COT-1 DNA, un mix di blocco fornito dal produttore e un buffer di ibridazione fornito dal produttore con un robot di liquido di movimentazione. NOTA: Queste coppie Hyb possono essere un campione e un riferimento, o un campione vs campione se CNVs condivisa non sono un problema (ad esempio, abbiamo regolarmente pair campioni fenotipo-non corrispondenti, come ad esempio una displasia paziente renale vs un paziente craniosinostosi, in quanto sono molto improbabile portare la stessa clinicamente significativa CNV). Se si utilizza un DNA di riferimento, si raccomanda una fornitura DNA commerciale, e dovrebbe essere elaborato fianco campione. <ol><li> Usando un trattamento liquido robot, aggiungere COT-1 DNA (3333 ng / ml), il fornito dal produttore di bloccaggio mix e tampone di ibridizzazione in ciascun pozzetto di una piastra a 96 pozzetti in modo che ogni pozzetto contiene 1,1 microlitri COT-1 DNA, 4,95 ml mix di blocco e 24.75 tampone di ibridazione microlitri. </li><li> Aggiungere 9.35 ml di DNA adeguato Cyanine 3-marcato in ciascun pozzetto. Pre-bagnato ogni suggerimento per migliorare accuratezza della dispensazione. </li><li> Aggiungere 9.35 ml di DNA Cyanine appropriata 5 marcato a ciascun bene. Pre-bagnato ogni suggerimento per migliorare accuratezza della dispensazione. </li><li> Sigillare la piastra a 96 pozzetti e vortex per 1 min. Spin la piastra a 96 pozzetti per raccogliere contenuti sul fondo di ciascun pozzetto. </li></ol></li></ol> 4. Ibridazione <ol><li> Preriscaldare il forno a 65 ° C e ibridazione preriscaldare una diapositiva di supporto e una camera di ibridazione per ogni diapositiva array. <ol><li> Denaturare il DNA marcato in incubazione pre-ibridazione prima di applicare agli array. Eseguire ibridazione in un forno rotante per 24 h. </li><li> Incubare la piastra a 96 pozzetti a 70 ° C per 30 min e poi lasciato a 37 ° C per almeno 5 minuti. </li><li> Lavorando ad una piattaforma riscaldata a 42 ° C, caricare ogni vetrino backup in una camera di ibridazione prima dell&#39;uso. Assicurarsi che la parte trasparente della slitta guarnizioni allinea con la parte &#39;finestrato&#39; della camera di ibridazione. </li><li> Dispensare 42 ml di mix ibridazione preparato in precedenza (vedi punto 3) sulla posizione appropriata sulla matrice sostegno diapositiva. Pre-bagnato ogni suggerimento per migliorare accuratezza della dispensazione. Pipettare lentamente sul centro di ciascuna posizione, assicurandosi che il liquido non tocchi il confine anello di gomma. </li><li> Una volta che tutte le posizioni sul vetrino supporto sono pieni, attenzione abbassare la diapositiva matrice su di esso e assemblare la camera di ibridazione. Assicurarsi che il lato della matrice con la scrittura su di esso si trova ad affrontare la diapositiva supporto. Assicurarsi di serrare la vite camera di ibridazione. </li><li> Ispezionare la camera di ibridazione assemblato. ENsure che non vi siano perdite di miscela di ibridazione fuori dei confini anello in gomma e ogni bolla d&#39;aria è ~ 4 mm quando la camera di ibridazione viene appoggiata sulla sua estremità verticalmente. Ruotare la camera di ibridazione e controllare che non vi siano bolle d&#39;aria che sono bloccati in posizione e non si muove. Se ci sono uno di questi, dare la camera di un forte tap in panchina. Verificare che tutte le bolle d&#39;aria si muovono. </li><li> Posizionare la camera di ibridazione in forno rotante a 65 ° C per 24 ore. Assicurarsi che il rotore del forno è equilibrato; utilizzare altre camere vuote se necessario. </li></ol></li></ol> 5. Lavaggio e la scansione di diapositive <ol><li> Lavare gli array per rimuovere l&#39;eccesso di DNA marcato e quindi eseguire la scansione per misurare la fluorescenza di ogni sonda. <ol><li> Prendere camere ibridazione di forno e smontare. Le diapositive di matrice e guarnizioni saranno incollati; immergere questi in tampone di lavaggio 1 e utilizzare un paio di plastica, pinze piatto da taglio per fare leva loro a parte. </li><li> Discard la diapositiva guarnizione e posizionare il vetrino array in un rack sommersa in tampone 1. </li><li> Lavare il vetrino array in ~ 700 ml di tampone di lavaggio fresco 1 per 5 min, agitando vigorosamente (utilizzare una pulce e un agitatore magnetico). </li><li> Trasferire il vetrino array per ~ 700 ml tampone di lavaggio 2 e lavare per 90 secondi, mescolando energicamente. Sollevare delicatamente le diapositive matrice su tampone di lavaggio 2, dovrebbero emergere a secco. </li><li> Caricare il vetrino array in un portavetrini dello scanner, utilizzando un protettore diapositiva. Caricare la diapositiva nello scanner matrice e la scansione seguendo le istruzioni del produttore della matrice. </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 non rileverà riarrangiamenti bilanciati o anomalie ploidia quali triploidia. Inoltre, basso livello squilibri mosaico non possono essere rilevati. Tuttavia, CGH array ha una risoluzione più alta per il rilevamento CNV di analisi cromosomica G-banded quale essa ha sostituito in molti laboratori di citogenetica. E &#39;quindi il gold standard attuale per tutto il genoma di rilevamento CNV. Essa può essere sostituito da tecnologie di sequenziamento di prossima generazione per il futuro, ma attualmente, il loro...

E &#39;noto da molti anni che delezioni o copie extra di segmenti cromosomici causano ritardo mentale, dismorfismi e malformazioni congentical, e in alcuni casi causare sindromi genetiche 1. Tuttavia, l&#39;unica tecnologia disponibile fino alla metà degli anni 2000 per la rilevazione genoma a livello di questi cambiamenti era G fasciato analisi cromosomica, che ha una risoluzione di circa 5-10 MB, a seconda della regione e la natura dello squilibrio, e che non può rilevare cromosomi anormali in cui il materiale è stato sostituito da una regione di un cromosoma differente con lo stesso pattern di bande. Ausiliari tecniche di citogenetica, come ibridazione fluorescente in situ e multiplex specifici legatura probe amplificazione sono stati disponibili per l&#39;interrogatorio di loci specifico, in caso di sospetto di squilibrio sindromico specifico, ma non è stato fino all&#39;introduzione della matrice ibridazione genomica comparativa (CGH array) nella routine clinica s diagnosticoervice 2-5 che il rilevamento a livello di genoma di numero di copie varianti (CNV) è diventato disponibile in forte aumento la risoluzione (in genere circa 120 KB). Lavori di manutenzione clinica accanto studi di ricerca hanno dimostrato che CNVs per alcune regioni sono molto diffuse nella popolazione normale 6-7, mentre altri CNVs, precedentemente non rilevabili, sono associati con neurodisabilities come l&#39;autismo e l&#39;epilessia 8-11. Il protocollo descritto in questo documento viene utilizzato nel nostro UK National Health Service (NHS) laboratorio di diagnosi clinica; usiamo strategie di ibridazione nuove, prove per lotto e robotica per minimizzare i costi di questo servizio finanziati dallo Stato. Prima il protocollo descritto di seguito, il DNA di alta qualità dovrebbe essere estratto dal materiale di partenza appropriati, comunemente sangue, cellule coltivate o campioni di tessuto. Spettrofotometria può essere utilizzato per misurare la concentrazione (dovrebbe essere&gt; 50 ng / ul) e controllare 260: 280 rapporti di assorbanza (dovrebbe be 1.8-2.0). Elettroforesi gel può essere utilizzato per verificare che il DNA è di alto peso molecolare senza degradazione significativa. Questo protocollo è stato progettato per i laboratori di throughput più elevate che sono l&#39;etichettatura 96 ​​campioni per analisi utilizzando la robotica automatizzata gestione dei liquidi. Tuttavia, può essere adattato per laboratori di throughput inferiori senza automazione.

<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.

Ogni sonda su una matrice ibrida è visualizzato come una miscela di fluorocromi rosso e verde (vedi Figura 1). Il rapporto di rosso al segnale verde fluorescente per ciascuna sonda viene quantificato dallo scanner e il relativo software traccia questi come rapporti log2 base alla loro posizione genomica, e identifica le regioni di confine preimpostati fuori. L&#39;array tracce risultanti permettono l&#39;interpretazione delle regioni identificate come genomicamente sbilanciato. Per esempio, la traccia ...

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 per la rilevazione di varianti del numero di copie genomiche ha sostituito l&#39;analisi del cariotipo G-fasciato. Questo articolo descrive la tecnologia e la sua applicazione in un laboratorio di servizio diagnostico.

Array Comparative Genomic Hybridization (CGH Array) per il rilevamento di Genomic Copy Number Varianti

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 Views.  Guy's & St Thomas' NHS Foundation Trust.  Array CGH per la rilevazione di varianti del numero di copie genomiche ha sostituito l'analisi del cariotipo G-fasciato. Questo articolo descrive la tecnologia e la sua applicazione in un laboratorio di servizio diagnostico. 

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

Isolation of Genomic DNA from Mouse Tails

Isolamento del DNA genomico da Tails mouse

Ricerca

Biologia

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.

Dimostrazione tecnica di ibridazione Whole Genome Array Comparative Genomic

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 per la cronica In vivo</emRegistrazione>: 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.

Inserire grande Ambientale Genomic Produzione Biblioteca

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 microarray: Esempio di controllo della qualità, ibridazione e scansione di array

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.

Genomica risonanza magnetica - una risorsa pubblica per lo Studio Patterns sequenza all&#39;interno del DNA genomico

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.

Schermi competitivo genomica delle Biblioteche di lievito con codice a barre

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.

Rilevamento di Rare varianti genomiche da Sequencing pool Uso 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.

Trasformazione genomica del 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.

Cattura selettiva di 5 hydroxymethylcytosine dal DNA genomico

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 ...