Name: chromatin immunoprecipitation (chip) protocol for low-abundance embryonic samples
Uploaded: 2017-08-29T14:00:00
Description: Watch this Scientific Journal Video about Chromatin Immunoprecipitation ChIP Protocol for Low-abundance Embryonic Samples at JoVE.com

Los autores agradecen a Jan Appel por su excelente asistencia técnica durante el establecimiento de este protocolo. Trabajo en el laboratorio de Rada-Iglesias es apoyado por CMMC intramuros financiación, becas de investigación de la DFG (RA 2547/1-1, RA 2547/2-1 y TE 1007/3-1), el investigador avanzado UoC grupo Grant y la beca del CECAD.

según las pautas de cuidado de los animales alemana, ninguna aprobación institucional cuidado Animal y el Comité uso (IACUC) era necesaria para llevar a cabo los experimentos de embrión de pollo. Según las directrices locales, sólo los experimentos con embriones de pollo HH44 (18 días) y mayores requieren la aprobación del IACUC. Sin embargo, los embriones utilizados en este estudio estaban en etapas tempranas del desarrollo embrionario (es decir, HH19 (72 h)).
 Nota: el prop...

<ol>
	<li>Jenuwein, T., Allis, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Translating+the+histone+code.">Translating the histone code.</a> Science. 293 (5532), 1074-1080 (2001).</li><li>Kouzarides, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chromatin+modifications+and+their+function.">Chromatin modifications and their function.</a> Cell. 128 (4), 693-705 (2007).</li><li>Wang, Z., Schones, D. E., Zhao, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+human+epigenomes.">Characterization of human epigenomes.</a> Curr Opin. Genet Dev. 19 (2), 127-134 (2009).</li><li>ENCODE Project Consortium. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+integrated+encyclopedia+of+DNA+elements+in+the+human+genome.">An integrated encyclopedia of DNA elements in the human genome.</a> Nature. 489 (7414), 57-74 (2012).</li><li>Roadmap Epigenomics Consortium. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Integrative+analysis+of+111+reference+human+epigenomes.">Integrative analysis of 111 reference human epigenomes.</a> Nature. 518 (7539), 317-330 (2015).</li><li>Heintzman, N. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histone+modifications+at+human+enhancers+reflect+global+cell-type-specific+gene+expression.">Histone modifications at human enhancers reflect global cell-type-specific gene expression.</a> Nature. 459 (7243), 108-112 (2009).</li><li>Rada-Iglesias, A., Bajpai, R., Swigut, T., Brugmann, S. A., Flynn, R. A., Wysocka, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+unique+chromatin+signature+uncovers+early+developmental+enhancers+in+humans.">A unique chromatin signature uncovers early developmental enhancers in humans.</a> Nature. 470 (7333), 279-283 (2011).</li><li>Creyghton, M. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histone+H3K27ac+separates+active+from+poised+enhancers+and+predicts+developmental+state.">Histone H3K27ac separates active from poised enhancers and predicts developmental state.</a> Proc Nat Acad Sci USA. 107 (50), 21931-21936 (2010).</li><li>Benayoun, B. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=H3K4me3+breadth+is+linked+to+cell+identity+and+transcriptional+consistency.">H3K4me3 breadth is linked to cell identity and transcriptional consistency.</a> Cell. 158 (3), 673-688 (2014).</li><li>Rehimi, 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=Epigenomics-Based+Identification+of+Major+Cell+Identity+Regulators+within+Heterogeneous+Cell+Populations.">Epigenomics-Based Identification of Major Cell Identity Regulators within Heterogeneous Cell Populations.</a> Cell Rep. 17 (11), 3062-3076 (2016).</li><li>Whyte, W. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Master+transcription+factors+and+mediator+establish+super-enhancers+at+key+cell+identity+genes.">Master transcription factors and mediator establish super-enhancers at key cell identity genes.</a> Cell. 153 (2), 307-319 (2013).</li><li>Valouev, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome-wide+analysis+of+transcription+factor+binding+sites+based+on+ChIP-Seq+data.">Genome-wide analysis of transcription factor binding sites based on ChIP-Seq data.</a> Nat Methods. 5 (9), 829-834 (2008).</li><li>Dahl, J. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Broad+histone+H3K4me3+domains+in+mouse+oocytes+modulate+maternal-to-zygotic+transition.">Broad histone H3K4me3 domains in mouse oocytes modulate maternal-to-zygotic transition.</a> Nature. 537 (7621), 548-552 (2016).</li><li>Rotem, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-cell+ChIP-seq+reveals+cell+subpopulations+defined+by+chromatin+state.">Single-cell ChIP-seq reveals cell subpopulations defined by chromatin state.</a> Nat Biotech. 33 (11), 1165-1172 (2015).</li><li>Schmidl, C., Rendeiro, A. F., Sheffield, N. C., Bock, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ChIPmentation:+fast,+robust,+low-input+ChIP-seq+for+histones+and+transcription+factors.">ChIPmentation: fast, robust, low-input ChIP-seq for histones and transcription factors.</a> Nat Methods. 12 (10), 963-965 (2015).</li><li>Zhang, B., 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=Allelic+reprogramming+of+the+histone+modification+H3K4me3+in+early+mammalian+development.">Allelic reprogramming of the histone modification H3K4me3 in early mammalian development.</a> Nature. 537 (7621), 553-557 (2016).</li><li>Hamburger, V., Hamilton, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+series+of+normal+stages+in+the+development+of+the+chick+embryo.">A series of normal stages in the development of the chick embryo.</a> Dev Dynam. 195 (4), 231-272 (1951).</li><li>Ho, J. W. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+analysis+of+metazoan+chromatin+organization.">Comparative analysis of metazoan chromatin organization.</a> Nature. 512 (7515), 449-452 (2014).</li><li>Calo, E., Wysocka, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modification+of+enhancer+chromatin:+what,+how,+and+why?.">Modification of enhancer chromatin: what, how, and why?.</a> Mol Cell. 49 (5), 825-837 (2013).</li><li>Spitz, F., Furlong, E. E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcription+factors:+from+enhancer+binding+to+developmental+control.">Transcription factors: from enhancer binding to developmental control.</a> Nat Rev Genetics. 13 (9), 613-626 (2012).</li></ol>

Epigenómica perfiles de modificación de las histonas con ChIP-seq pueden utilizarse para mejorar la anotación funcional de genomas vertebrados en diferentes contextos celulares4,5,18. Estos perfiles epigenómica pueden utilizarse, entre otras cosas, para identificar elementos de reforzador, para definir el estado regulador de potenciadores (es decir, activo, preparado, o preparada) y definir los reguladores de identi...

Modificaciones post-traduccionales de las histonas están directamente involucradas en diversos procesos dependiente de la cromatina, incluyendo transcripción, replicación y reparación de ADN1,2,3. Además, modificaciones de las histonas diferentes muestran positivos (por ejemplo, H3K4me3 y H3K27ac) o negativo (por ejemplo, H3K9me3 y H3K27me3) correlaciones con la expresión de genes y puede ser definido ampliamente como marcas de activación o represión de la histona, respectivamente2,3. En consecuencia, los mapas de modificación global de la histona, también conocidos como mapas epigenómicos, han surgido como herramientas poderosas y universales para funcionalmente anotar genomas vertebrados4,5. Por ejemplo, secuencias reguladoras distales como potenciadores pueden ser identificados basan en la presencia de firmas de cromatina específicos (por ejemplo, activos potenciadores: H3K4me1 y H3K27ac), que distinguen de las regiones del promotor proximal (por ejemplo, promotores activos: H3K4me3)6,7,8. Por otra parte, los genes con funciones reguladoras de la identidad de células grandes suelen encontrarse con dominios de cromatina amplio marcados con H3K4me3 o H3K27me3, dependiendo del estado transcripcionalmente activo o inactivo de los genes subyacentes, respectivamente9 ,10. Del mismo modo, la expresión de los genes de identidad principales de la célula parece ser controlados con frecuencia por múltiples y espacialmente agrupados potenciadores (es decir, súper potenciadores), que pueden ser identificados como amplios dominios marcados H3K27ac11.
En la actualidad, histona modificación mapas son generados usando la tecnología de ChIP-seq, que en comparación con los anteriores enfoques como ChIP-chip (ChIP juntada a microarrays) proporciona mayor resolución, menos artefactos, menos ruido, mayor cobertura y menor cuesta12. Sin embargo, la generación de los mapas epigenómicos utilizando la tecnología de ChIP-seq tiene sus limitaciones inherentes, sobre todo asociadas a la capacidad para realizar con éxito el ChIP en las muestras de interés. Protocolos de ChIP tradicionales típicamente requieren millones de células, que limitan la aplicabilidad de este método a celular in vitro de líneas o células que puede ser fácilmente aisladas en vivo (por ejemplo, las células de sangre). En los últimos años, un número de protocolos modificados de ChIP compatibles con un número bajo de células ha sido descritas13,14,15,16. Sin embargo, estos protocolos están diseñados para acoplarse con secuenciación de próxima generación (es decir, ChIP-seq), y por lo general utilizan ad hoc biblioteca preparación métodos13,14, 15 , 16.
Aquí, hemos descrito un protocolo de ChIP que puede utilizarse para investigar perfiles de modificación de histonas mediante un número bajo a intermedio de células (5 x 104 - 5 x 105 células) en cualquiera de los dos loci seleccionados (es decir, ChIP-qPCR) o global (, es decir, ChIP-seq) (figura 1). Cuando se acopla a la tecnología ChIP-seq, nuestro protocolo de ChIP puede utilizarse junto con métodos de preparación de la biblioteca estándar, por lo que es ampliamente accesible a muchos laboratorios10. Este protocolo se ha utilizado para investigar varias marcas de histona (p. ej., H3K4me3, H3K27me3 y H3K27ac) en los tejidos embrionarios de pollo diferentes (p. ej., tubo neural espinal (SNT), prominencias frontonasal y epiblasto). Sin embargo, esperamos que sea ampliamente aplicable a otros organismos en que biológicamente o clínicamente relevantes muestras pueden obtenerse solamente en cantidades bajas.

<table>
	<tbody>
		<tr>
			<td>Reagent</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>BSA powder</td>
			<td>Carl Roth</td>
			<td>3737.3</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate Saline buffer (PBS)</td>
			<td>Sigma Aldrich</td>
			<td>D8537</td>
			<td></td>
		</tr>
		<tr>
			<td>Tris-HCL pH8.0</td>
			<td>Sigma Aldrich</td>
			<td>T1503</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Carl Roth</td>
			<td>3957.2</td>
			<td></td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>Carl Roth</td>
			<td>8043.2</td>
			<td></td>
		</tr>
		<tr>
			<td>EGTA</td>
			<td>Carl Roth</td>
			<td>3054.2</td>
			<td></td>
		</tr>
		<tr>
			<td>Na-Deoxycholate</td>
			<td>Sigma Aldrich</td>
			<td>D6750-24</td>
			<td></td>
		</tr>
		<tr>
			<td>N-lauroylsarcosine</td>
			<td>Sigma Aldrich</td>
			<td>61743-25G</td>
			<td></td>
		</tr>
		<tr>
			<td>Hepes</td>
			<td>Applichem</td>
			<td>A3724,0250</td>
			<td></td>
		</tr>
		<tr>
			<td>LiCl</td>
			<td>Carl Roth</td>
			<td>3739.2</td>
			<td></td>
		</tr>
		<tr>
			<td>NP-40</td>
			<td>Sigma Aldrich</td>
			<td>I3021-100ml</td>
			<td></td>
		</tr>
		<tr>
			<td>SDS</td>
			<td>Carl Roth</td>
			<td>1833</td>
			<td></td>
		</tr>
		<tr>
			<td>Protein G/magnetic beads</td>
			<td>Invitrogen</td>
			<td>1004D</td>
			<td></td>
		</tr>
		<tr>
			<td>37% Formaldehyde</td>
			<td>Sigma Aldrich</td>
			<td>252549-1L</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>RNase</td>
			<td>Peqlab</td>
			<td>12-RA-03</td>
			<td></td>
		</tr>
		<tr>
			<td>Proteinase K</td>
			<td>Sigma Aldrich</td>
			<td>46.35 E</td>
			<td></td>
		</tr>
		<tr>
			<td>Na-butyrate</td>
			<td>Sigma Aldrich</td>
			<td>SLB2659V</td>
			<td></td>
		</tr>
		<tr>
			<td>Proteinase inhibitor</td>
			<td>Roche</td>
			<td>5892791001</td>
			<td></td>
		</tr>
		<tr>
			<td>SYBRgreen Mix</td>
			<td>biozym</td>
			<td>617004</td>
			<td></td>
		</tr>
		<tr>
			<td>dH2O</td>
			<td>Sigma Aldrich</td>
			<td>W4502</td>
			<td></td>
		</tr>
		<tr>
			<td>1Kb ladder</td>
			<td>Thermofisher</td>
			<td>SM1333</td>
			<td></td>
		</tr>
		<tr>
			<td>Orange G</td>
			<td>Sigma Alrich</td>
			<td>03756-25</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Invitrogen</td>
			<td>16500-500</td>
			<td></td>
		</tr>
		<tr>
			<td>0.25% Trypsin-EDTA (1X)</td>
			<td>Gibco</td>
			<td>25200-072</td>
			<td></td>
		</tr>
		<tr>
			<td>Octylphenol Ethoxylate (Triton X 100)</td>
			<td>Roth</td>
			<td>3051.4</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM (Dulbecco&#180;s Modified Eagle Medium)</td>
			<td>Gibco</td>
			<td>31331-028</td>
			<td></td>
		</tr>
		<tr>
			<td>Gel loading tips Multiflex</td>
			<td>A.Hartenstein</td>
			<td>GS21</td>
			<td></td>
		</tr>
		<tr>
			<td>qPCR Plates</td>
			<td>Sarstedt</td>
			<td>721,985,202</td>
			<td></td>
		</tr>
		<tr>
			<td>384 well</td>
			<td>Sarstedt</td>
			<td>721,985,202</td>
			<td></td>
		</tr>
		<tr>
			<td>1.5 mL tubes</td>
			<td>Sarstedt</td>
			<td>72,706</td>
			<td></td>
		</tr>
		<tr>
			<td>100-1000&#181;l Filter tips</td>
			<td>Sarstedt</td>
			<td>70,762,211</td>
			<td></td>
		</tr>
		<tr>
			<td>2-20&#181;l Filter tips</td>
			<td>Sarstedt</td>
			<td>70,760,213</td>
			<td></td>
		</tr>
		<tr>
			<td>2-200&#181;l Filter tips</td>
			<td>Sarstedt</td>
			<td>70,760,211</td>
			<td></td>
		</tr>
		<tr>
			<td>0.5-10&#181;l Filter tips</td>
			<td>Sarstedt</td>
			<td>701,116,210</td>
			<td></td>
		</tr>
		<tr>
			<td>H3K27me3 antibody</td>
			<td>Active Motif</td>
			<td>39155</td>
			<td></td>
		</tr>
		<tr>
			<td>H3K27ac antibody</td>
			<td>Active Motif</td>
			<td>39133</td>
			<td></td>
		</tr>
		<tr>
			<td>H3K4me3 antibody</td>
			<td>Active Motif</td>
			<td>39159</td>
			<td></td>
		</tr>
		<tr>
			<td>H3K4me2 antibody</td>
			<td>Active Motif</td>
			<td>39141</td>
			<td></td>
		</tr>
		<tr>
			<td>End Repair Mix</td>
			<td>Illumina</td>
			<td>FC-121-4001</td>
			<td></td>
		</tr>
		<tr>
			<td>Paramagnetic beads</td>
			<td>Beckman Coulter</td>
			<td>A63881</td>
			<td></td>
		</tr>
		<tr>
			<td>Resuspension buffer</td>
			<td>Illumina</td>
			<td>FC-121-4001</td>
			<td></td>
		</tr>
		<tr>
			<td>A-Tailing Mix</td>
			<td>Illumina</td>
			<td>FC-121-4001</td>
			<td></td>
		</tr>
		<tr>
			<td>Ligation Mix</td>
			<td>Illumina</td>
			<td>FC-121-4001</td>
			<td></td>
		</tr>
		<tr>
			<td>RNA Adapter Indexes</td>
			<td>Illumina</td>
			<td>RS-122-2101</td>
			<td></td>
		</tr>
		<tr>
			<td>Stop Ligation Buffer</td>
			<td>Illumina</td>
			<td>FC-121-4001</td>
			<td></td>
		</tr>
		<tr>
			<td>PCR Primer Cocktail</td>
			<td>Illumina</td>
			<td>FC-121-4001</td>
			<td></td>
		</tr>
		<tr>
			<td>Enhanced PCR Mix</td>
			<td>Illumina</td>
			<td>FC-121-4001</td>
			<td></td>
		</tr>
		<tr>
			<td>Genomic DNA ladder</td>
			<td>Agilent</td>
			<td>5067-5582</td>
			<td></td>
		</tr>
		<tr>
			<td>Elution Buffer</td>
			<td>Agilent</td>
			<td>19086</td>
			<td></td>
		</tr>
		<tr>
			<td>Sample Buffer</td>
			<td>Agilent</td>
			<td>5067-5582</td>
			<td></td>
		</tr>
		<tr>
			<td>Library Quantification Kit</td>
			<td>Kapa Biosystems</td>
			<td>KK4835 &#8211; 07960204001</td>
			<td></td>
		</tr>
		<tr>
			<td>Fertile chicken white eggs</td>
			<td>LSL Rhein Main</td>
			<td>KN: 15968</td>
			<td></td>
		</tr>
		<tr>
			<td>Needle (Neoject)</td>
			<td>A.Hartenstein</td>
			<td>10001</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe (Ecoject 10ml)</td>
			<td>Dispomed witt oHG</td>
			<td>21010</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Hermle</td>
			<td>Z 216 MK</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermoshaker</td>
			<td>ITABIS</td>
			<td>MKR13</td>
			<td></td>
		</tr>
		<tr>
			<td>Sonicator</td>
			<td>Active Motive</td>
			<td>EpiShear probe sonicator</td>
			<td></td>
		</tr>
		<tr>
			<td>Sonicator</td>
			<td>Diagenode</td>
			<td>Bioruptor Plus</td>
			<td></td>
		</tr>
		<tr>
			<td>Rotator</td>
			<td>Stuart</td>
			<td>SB3</td>
			<td></td>
		</tr>
		<tr>
			<td>Variable volume (5&#8211;1,000 &#956;l) pipettes</td>
			<td>Eppendorf</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Timer</td>
			<td>Sigma</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic holder</td>
			<td>Thermo Fisher</td>
			<td>DynaMag-2 12321D</td>
			<td></td>
		</tr>
		<tr>
			<td>Table spinner</td>
			<td>Heathrow Scientific</td>
			<td>Sprout</td>
			<td></td>
		</tr>
		<tr>
			<td>Mixer</td>
			<td>LMS</td>
			<td>VTX 3000L</td>
			<td></td>
		</tr>
		<tr>
			<td>Real-Time PCR Cycler</td>
			<td>Roche</td>
			<td>Light Cycler; Serial Nr.5662</td>
			<td></td>
		</tr>
		<tr>
			<td>PCR Cycler</td>
			<td>Applied Biosystems</td>
			<td>Gene Amp PCR System 9700</td>
			<td></td>
		</tr>
		<tr>
			<td>DNA and RNA quality control system</td>
			<td>Agilent</td>
			<td>Agilent 4200 TapeStation System</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Dumont</td>
			<td>5-Inox-H</td>
			<td></td>
		</tr>
		<tr>
			<td>Perforated spoon</td>
			<td>World precision instruments</td>
			<td>501997</td>
			<td></td>
		</tr>
	</tbody>
</table>

chromatin immunoprecipitation (chip) protocol for low-abundance embryonic samples

Inmunoprecipitación de cromatina (ChIP) es una técnica ampliamente utilizada para el mapeo de la localización de modificación postraduccional de las histonas, variantes de las histonas, factores de transcripción o enzimas modificadores de la cromatina en un locus determinado o en una escala genoma-ancha. La combinación de ensayos de ChIP con secuenciación de próxima generación (es decir, ChIP-Seq) es un enfoque poderoso para descubrir todo el mundo redes reguladoras del gene y para mejorar la anotación funcional del genoma, especialmente de secuencias reguladoras no codificantes. Protocolos de chIP normalmente requieren grandes cantidades de material celular, así que la aplicabilidad de este método a la investigación de tipos raros de la célula o biopsias de tejido pequeño. Para hacer el ensayo de ChIP compatible con la cantidad de material biológico que se puede obtener normalmente en vivo durante la embriogénesis temprana de vertebrados, se describe aquí un protocolo simplificado de ChIP en el que el número de pasos necesarios para completar la ensayo fueron reducidas para minimizar la pérdida de muestra. Este protocolo de ChIP se ha utilizado con éxito para investigar modificaciones de las histonas diferentes en varios embrionario pollo y ratón adulto tejidos utilizando baja a un número medio de células (5 x 104 - 5 x 105 células). Lo importante, este protocolo es compatible con la tecnología ChIP-seq con métodos de preparación de la biblioteca estándar, proporcionando epigenómica global mapas en tejidos embrionarios muy relevantes.

Para ilustrar el funcionamiento de nuestro protocolo de viruta, se realizaron experimentos utilizando secciones SNT agrupadas de embriones de pollo de HH19, las prominencias maxilares de HH22 pollo embriones y embriones de pollo HH3 etapa para investigar los perfiles de unión de ChIP-seq varias modificaciones de las histonas (es decir, H3K4me2, H3K27ac, H3K4me3 y H3K27me3). Una vez que se obtuvieron ADNs de viruta, se evaluó la eficacia de la sonicación por electroforesis del ...

Watch this Scientific Journal Video about Chromatin Immunoprecipitation ChIP Protocol for Low-abundance Embryonic Samples at JoVE.com

Chromatin Immunoprecipitation ChIP Protocol for Low-abundance Embryonic Samples

Aquí, describimos una inmunoprecipitación de cromatina (ChIP) y el protocolo de preparación de biblioteca de ChIP-seq para generar perfiles de epigenómica global de muestras embrionarias de pollo baja abundancia.

Cromatina (ChIP) de la inmunoprecipitación protocolo para muestras embrionarias baja abundancia

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

The overall goal of this procedure is to investigate the binding profiles of different histone modifications, using low-abundance embryonic samples in order to improve the functional annotation of vertebrate genomes. This method can help answer key questions in the developmental biology field such as, which are the key enhancers and genes defining the identity of a particular embryonic tissue. The main advantages of this techniques are that it requires a limited amount of particular material and it can also be used for both local specific and genome wide analysis.Though this method can provide insights into transcription regulation or cellular heterogeneity with the embryonic tissues, it can also be applied to other systems such as, patent samples. To obtain stage HH19, chicken embryos for this experiment, incubate fertile white Leghorn hen eggs in horizontal orientation at 37 degrees celsius and 80%humidity for three days. To start isolating the HH19 embryos, make them accessible by extracting three milliliters of albumin with a 10 millimeter syringe to lower the blastoderm.In order to remove extra embryonic membranes, use fine scissors to make a small opening in the eye. Add one milliliter of lock solution. With the help of a bended needle, add 0.5 milliliters of Indian black ink.Use fine surgical scissors and forceps to cut off the extra embryonic membrane that surrounds the embryo. Then, transfer the embryo with a perforated spoon to a 4.5 centimeter petri dish containing 20 milliliters of PBS solution. Working on ice under a stereo microscope, use fine scissors and forceps to dissect and discard the amnion and the remaining parts of extra embryonic membrane.Then, cut the transverse spinal neuro tube or SNT segment at the brachial level of the embryo. Extend the dissection caudally into the thoracic region to isolate the SNT. To finish, use forceps to remove the tissues that laterally and ventrally surround the SNT.After isolating SNTs, immerse each segment in a 3.5 centimeter petri dish containing 37 degree celsius warm trypsin. When loosening of the non-neuro tissues around the SNT is visible under a stereo microscope, transfer the samples into cold 1x PBS. To stop the trypsinization, transfer the samples into a new dish with cold DMEM containing 10%FBS.Use forceps to manually remove the remaining mesenchymal and ectodermal tissues from the SNT. Transfer this clean SNT section to a 1.5 milliliter tube and flash freeze it in liquid nitrogen. Next, homogenize the tissue according to the text protocol.Add 13.5 microliters of 37%formaldehyde and incubate at room temperature on a rotator for 15 minutes. To quench the formaldehyde, add 25 microliters of 2.5 molar glycine to the tube and incubate at room temperature on a rotator for 10 minutes. Centrifuge the tube and then, wash the pellet according to the text protocol.After crosslinking, re-suspend the pellet in 300 microliters of ice cold, complete lysis buffer by pipetting. Incubate the samples at four degrees celsius on a rocking platform for 10 minutes. Next, sonicate the samples at four degrees celsius.After sonication, centrifuge the samples at 16, 000 x G at four degrees celsius for 10 minutes. Transfer the supernatant or lysate to a fresh 1.5 milliliter tube and discard the cellular debris pellet. Dilute the lysate according to the text protocol.Then, keep a small aliquot of each sample as input control and freeze at 20 degrees celsius. Incubate the remaining samples that will be subjected to chromatin precipitation or chip with appropriate antibodies according to the text protocol. Then, add 300 microliters of antibody bound chromatin to previously washed magnetic beads.Invert the tubes to mix the samples. To bind the antibodies to the beads, place the tubes on a tube rotator and rotate vertically at four degree celsius for a minimum of four hours. To wash the chromatin bound beads, add one milliliter of ice cold RIPA wash buffer to the tube kept on ice and mix by inverting or flicking the tube.After placing the tube into the magnetic holder at room temperature, wait for the beads to settle on the side. Pour off the clear liquid and repeat this wash three more times. After adding one milliliter of TE 50 millimolar sodium chloride to the tube, transfer the chromatin bound beads in this solution to a fresh 1.5 millimeter microcentrifuge tube.Place the tube into the magnetic holder and when the beads have settled, pour off the liquid. Next, centrifuge the beads at 900 x G at four degrees celsius for three minutes in a pre-cooled centrifuge. After the beads have been settled in the magnetic holder, remove all remaining TE using a gel loading tip.Working at room temperature, add 210 microliters of elution buffer to the beads and re-suspend by flicking. Incubate the tube in a pre-warmed heat block at 65 degree celsius for 15 minutes, while shaking. After incubation, centrifuge the tubes with the beads at 16, 000 x G at room temperature, for one minute.Once the beads have settled in the magnetic holder, transfer the supernatant to a fresh microcentrifuge tube. Thaw the previously frozen input control sample from 20 degrees celsius to room temperature. Add 90 microliters of elution buffer to the sample and mix by briefly vortexing.To reverse the cross-links, incubate the chip and control samples at 65 degrees celsius overnight. Working at room temperature, add one volume of TE buffer per tube and invert to mix. To digest the RNA, add RNAse A to the control and chip samples to a final concentration of 0.2 milligrams per milliliter and invert the tubes to mix.Incubate the tubes in a pre-warmed heat block at 37 degrees celsius for two hours. To digest the protein for the subsequent DNA purification, add protease K to a final concentration of 0.2 milligrams per milliliters to the tubes and invert the tubes to mix. Incubate the tubes in a pre-warmed heat block at 55 degrees celsius for two hours.Extract and purify the DNA according to the supplementary materials. This DNA can now be used for quantitative PCR and chip seek library preparation. Sonication efficiency essential for a successful chip is confirmed by agarose gel electrophoresis of the input control samples.In this example, using chicken spinal neural tube or SNT sections, 11 sonication cycles were used to obtain an optimal fragment size ranging from 200 to 500 base pairs. Chipped DNA was analyzed by quantitative PCR to measure the enrichment levels of activating and repressive histone marks around the promoter regions of genes that are active and inactive in the chicken SNT. This shows that it is possible to evaluate the chipped quality by quantifying only a few low side without losing much DNA for further analysis.After chip seek libraries were prepared in sequence, a representative locust is shown for H3K27 tri methylation and H3K4 tri methylation chip seek data generated in chicken SNT. Similar chip seek profiles were also successfully generated in different chicken embryonic tissues, such as maxillary prominences and stage HH3 embryos. This demonstrates that here presented, chip protocol can be used to generate epigenomic profiles from limited amounts of various embryonic tissues.By using this protocol to generate the histone modification profiles in an embryonic tissue, it is important to remember that signals will come from all different cell types present in such tissue. Following this protocol and using more starting biological material, it should be possible to investigate the binding profiles of other proteins involved in transcriptional regulation, such as, transcription factors, co-activators or RNA polymerase 2 sub units. Once established, these protocols will enable researchers in the field of developmental biology or medical genetics to improve the functional alteration of vertebrate genomes and to gain important insights into the molecular basis of myogenesis, evolution and human disease.

Research

JoVE Journal

Genetics

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

Sequential Salt Extractions for the Analysis of Bulk Chromatin Binding Properties of Chromatin Modifying Complexes

Extracciones secuenciales de sal para el análisis de la cromatina a granel enlace propiedades de cromatina, complejos de modificar

Elucidation of the binding properties of chromatin-targeting proteins can be very challenging due to the complex nature of chromatin and the heterogeneous ...

Investigación

Genética

Analysis of the c-KIT Ligand Promoter Using Chromatin Immunoprecipitation

Análisis del promotor de ligandos c-KIT usando inmunoprecipitación de cromatina

Multiple cellular processes, including DNA replication and repair, DNA recombination, and gene expression, require interactions between proteins and DNA. ...

Chromatin Immunoprecipitation (ChIP) in Mouse T-cell Lines

Chromatin Immunoprecipitation ChIP in Mouse T-cell Lines

Inmunoprecipitación de cromatina (ChIP) en líneas de células T de ratón

Signaling pathways regulate gene expression programs via the modulation of the chromatin structure at different levels, such as by post-translational ...

Generation of Native Chromatin Immunoprecipitation Sequencing Libraries for Nucleosome Density Analysis

Generación de inmunoprecipitación de la cromatina nativa secuenciación bibliotecas para el análisis de densidad de nucleosoma

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

Chromatin Immunoprecipitation (ChIP) of Histone Modifications from Saccharomyces cerevisiae

Chromatin Immunoprecipitation ChIP of Histone Modifications from Saccharomyces cerevisiae

Inmunoprecipitación de cromatina (ChIP) de modificaciones de las histonas de Saccharomyces cerevisiae

Histone post-translational modifications (PTMs), such as acetylation, methylation and phosphorylation, are dynamically regulated by a series of enzymes ...

Chromatin Immunoprecipitation of Murine Brown Adipose Tissue

Inmunoprecipitación de cromatina del tejido adiposo marrón murino

Most cellular processes are regulated by transcriptional modulation of specific gene programs. Such modulation is achieved through the combined actions of ...

Chromatin Immunoprecipitation Assay Using Micrococcal Nucleases in Mammalian Cells

Ensayo de inmunoprecipitación de cromatina utilizando nucleasas microcócticas en células de mamíferos

To express cellular phenotypes in organisms, living cells execute gene expression accordingly, and transcriptional programs play a central role in gene ...

Discovering CsgD Regulatory Targets in Salmonella Biofilm Using Chromatin Immunoprecipitation and High-Throughput Sequencing (ChIP-seq)

Discovering CsgD Regulatory Targets in Salmonella Biofilm Using Chromatin Immunoprecipitation and High-Throughput Sequencing ChIP-seq

Descubrimiento de objetivos reguladores de CsgD en biofilm de Salmonella utilizando inmunoprecipitación de cromatina y secuenciación de alto rendimiento (ChIP-seq)

Chromatin immunoprecipitation followed by sequencing (ChIP-seq) is a technique that can be used to discover the regulatory targets of transcription ...

High-Resolution Mapping of Protein-DNA Interactions in Mouse Stem Cell-Derived Neurons using Chromatin Immunoprecipitation-Exonuclease (ChIP-Exo)

High-Resolution Mapping of Protein-DNA Interactions in Mouse Stem Cell-Derived Neurons using Chromatin Immunoprecipitation-Exonuclease ChIP-Exo

Mapeo de alta resolución de interacciones proteína-ADN en neuronas derivadas de células madre del ratón utilizando inmunoprecipitación de cromatina-exonucleasa (ChIP-Exo)

Identification of specific protein-DNA interactions on the genome is important for understanding gene regulation. Chromatin immunoprecipitation coupled ...

Genome-wide Analysis of Histone Modifications Distribution using the Chromatin Immunoprecipitation Sequencing Method in Magnaporthe oryzae

Genome-wide Analysis of Histone Modifications Distribution using the Chromatin Immunoprecipitation Sequencing Method in Magnaporthe oryzae

Análisis de todo el genoma de la distribución de modificaciones de histonas utilizando el método de secuenciación de inmunoprecipitación de cromatina en Magnaporthe oryzae

Chromatin immunoprecipitation sequencing (ChIP-seq) is a powerful and widely used molecular technique for mapping whole genome locations of transcription ...