Name: pooled shrna screen for reactivation of mecp2 on the inactive x chromosome
Uploaded: 2018-03-02T13:00:00
Description: Watch this Scientific Journal Video about Pooled shRNA Screen for Reactivation of MeCP2 on the Inactive X Chromosome at JoVE.com

Agradecemos a Ross Dickins de la Universidad de Melbourne para proporcionar amablemente la biblioteca shRNA utilizada en la pantalla. Este trabajo fue financiado por Rett síndrome Research Trust (A.B.).

Todos los pasos que involucran animales se llevaron a cabo utilizando protocolos de actuación aprobados por el Fred Hutchinson cáncer Research Center institucional Animal cuidado y el Comité uso (IACUC). No reactivos utilizados aquí conocen a riesgos significativos para la salud humana a excepción de la 5-azacitidina (5-AZA).
1. generar una línea de celular de reportero con MeCP2- LUC-HR transgen en el Xi
<ol><li>
Preparación de fibroblastos de ratón tendón de una h...

<ol>
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E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rett+syndrome+is+caused+by+mutations+in+X-linked+MECP2,+encoding+methyl-CpG-binding+protein+2.">Rett syndrome is caused by mutations in X-linked MECP2, encoding methyl-CpG-binding protein 2.</a> Nat Genet. 23, 185-188 (1999).</li><li>Guy, J., Gan, J., Selfridge, J., Cobb, S., Bird, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversal+of+neurological+defects+in+a+mouse+model+of+Rett+syndrome.">Reversal of neurological defects in a mouse model of Rett syndrome.</a> Science. 315, 1143-1147 (2007).</li><li>Maduro, C., de Hoon, B., Gribnau, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fitting+the+Puzzle+Pieces:+the+Bigger+Picture+of+XCI.">Fitting the Puzzle Pieces: the Bigger Picture of XCI.</a> Trends Biochem Sci. 41, 138-147 (2016).</li><li>Disteche, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dosage+compensation+of+the+sex+chromosomes+and+autosomes.">Dosage compensation of the sex chromosomes and autosomes.</a> Semin Cell Dev Biol. 56, 9-18 (2016).</li><li>Wang, 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=Wild-type+microglia+do+not+reverse+pathology+in+mouse+models+of+Rett+syndrome.">Wild-type microglia do not reverse pathology in mouse models of Rett syndrome.</a> Nature. 521, E1-E4 (2015).</li><li>Sripathy, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Screen+for+reactivation+of+MeCP2+on+the+inactive+X+chromosome+identifies+the+BMP/TGF-beta+superfamily+as+a+regulator+of+XIST+expression.">Screen for reactivation of MeCP2 on the inactive X chromosome identifies the BMP/TGF-beta superfamily as a regulator of XIST expression.</a> Proc Natl Acad Sci U S A. 114, 1619-1624 (2017).</li><li>Foster, S. A., Galloway, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+papillomavirus+type+16+E7+alleviates+a+proliferation+block+in+early+passage+human+mammary+epithelial+cells.">Human papillomavirus type 16 E7 alleviates a proliferation block in early passage human mammary epithelial cells.</a> Oncogene. 12, 1773-1779 (1996).</li><li>Hnasko, T. S., Hnasko, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Western+Blot.">The Western Blot.</a> Methods Mol Biol. 1318, 87-96 (2015).</li><li>Strezoska, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimized+PCR+conditions+and+increased+shRNA+fold+representation+improve+reproducibility+of+pooled+shRNA+screens.">Optimized PCR conditions and increased shRNA fold representation improve reproducibility of pooled shRNA screens.</a> PLoS One. 7, e42341 (2012).</li><li>Green, M. R., Sambrook, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+High-Molecular-Weight+DNA+from+Mammalian+Tissues+Using+Proteinase+K+and+Phenol.">Isolation of High-Molecular-Weight DNA from Mammalian Tissues Using Proteinase K and Phenol.</a> Cold Spring Harb Protoc. 2017, (2017).</li><li>Goto, Y., Takagi, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tetraploid+embryos+rescue+embryonic+lethality+caused+by+an+additional+maternally+inherited+X+chromosome+in+the+mouse.">Tetraploid embryos rescue embryonic lethality caused by an additional maternally inherited X chromosome in the mouse.</a> Development. 125, 3353-3363 (1998).</li><li>Csankovszki, G., Nagy, A., Jaenisch, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synergism+of+Xist+RNA,+DNA+methylation,+and+histone+hypoacetylation+in+maintaining+X+chromosome+inactivation.">Synergism of Xist RNA, DNA methylation, and histone hypoacetylation in maintaining X chromosome inactivation.</a> J Cell Biol. 153, 773-784 (2001).</li><li>Minajigi, 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=Chromosomes.+A+comprehensive+Xist+interactome+reveals+cohesin+repulsion+and+an+RNA-directed+chromosome+conformation.">Chromosomes. A comprehensive Xist interactome reveals cohesin repulsion and an RNA-directed chromosome conformation.</a> Science. 349, (2015).</li><li>McHugh, C. 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=The+Xist+lncRNA+interacts+directly+with+SHARP+to+silence+transcription+through+HDAC3.">The Xist lncRNA interacts directly with SHARP to silence transcription through HDAC3.</a> Nature. 521, 232-236 (2015).</li><li>Bhatnagar, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+and+pharmacological+reactivation+of+the+mammalian+inactive+X+chromosome.">Genetic and pharmacological reactivation of the mammalian inactive X chromosome.</a> Proc Natl Acad Sci U S A. 111, 12591-12598 (2014).</li><li>Minkovsky, 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=The+Mbd1-Atf7ip-Setdb1+pathway+contributes+to+the+maintenance+of+X+chromosome+inactivation.">The Mbd1-Atf7ip-Setdb1 pathway contributes to the maintenance of X chromosome inactivation.</a> Epigenetics Chromatin. 7, 12 (2014).</li><li>Minkovsky, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-throughput+screen+of+inactive+X+chromosome+reactivation+identifies+the+enhancement+of+DNA+demethylation+by+5-aza-2'-dC+upon+inhibition+of+ribonucleotide+reductase.">A high-throughput screen of inactive X chromosome reactivation identifies the enhancement of DNA demethylation by 5-aza-2'-dC upon inhibition of ribonucleotide reductase.</a> Epigenetics Chromatin. 8, 42 (2015).</li></ol>

En nuestro estudio reciente6, hemos generado una línea celular murina con luciferasa y genes de resistencia a Higromicina fusionado a MeCP2 en el Xi y transduced con una biblioteca de > 60.000 shRNAs dirigidos a > 25.000 genes. Se encontraron 30 genes cuya ventaja en la supervivencia conferida precipitación en higromicina B selección, sugiriendo su papel en el control de MeCP2 y silenciamiento del cromosoma x. Estos resultados fueron validados por transducción de la línea ce...

Una las formas más comunes de deficiencia mental hereditaria en las mujeres, el síndrome de Rett, es causada por mutaciones heterozigóticas en MeCP2, un gen del cromosoma x que codifica una proteína esencial para la función neuronal normal1. Un enfoque potencial para el tratamiento de este trastorno sería la reactivación del alelo tipo salvaje de MeCP2 en la Xi, como restauración de expresión MeCP2 fue demostrado revertir déficits neurológicos en un modelo de ratón de esta enfermedad1, 2 , 4. sin embargo, silenciamiento epigenético de uno de los dos cromosomas en las células femeninas de X se mantiene bien durante toda la vida de un organismo3,4, y sólida reactivación de un gen Xi probablemente requeriría una mayor interrupción en múltiples vías de regulación epigenéticas.
Para identificar los factores necesarios para el mantenimiento del silenciamiento de MeCP2 , primero desarrollamos un modelo de ratón transgénico con una fusión de genes de resistencia MeCP2- luciferasa - Higromicina (MeCP2-LUC-HR) en uno de los dos cromosomas X (X MeCP2-LUC-HR/XMeCP2)5. Aunque el MeCP2 expresada desde la construcción de la fusión demostró para ser inestable y dio lugar a una pérdida de función, fenotípicamente mímico eliminación de MeCP2 en varones hemizygous (X /YMeCP2-LUC-HR), la expresión de los genes del reportero era fácilmente perceptible en un patrón consistente con la expresión endógena de MeCP25. A continuación genera clones del fibroblasto inmortalizado con el constructo en el cromosoma x inactivo o activo y confirmó que el ex expresó tipo MeCP2 y no la construcción de reportero; el inverso era verdad para estos últimos. Cuando se expone a un ADN desmetilantes agente conocido derogar silenciamiento génico, 5-azacitidina (5-AZA), las células con el reportero de la Xi ("células de reportero") ganaron la actividad en un ensayo de bioluminiscencia, que indica que la construcción podría ser reactivado y por lo tanto utilizado para la investigación genética.
A continuación desarrollamos una pantalla genética de alto rendimiento para los reguladores del silenciamiento de MeCP2 . La línea celular de reportero primero fue infectada con una biblioteca retroviral que contiene > 60.000 diferentes shRNAs dirigidos a > 25.000 genes en el genoma de ratón5,6y después sometida a higromicina B selección. Se comparó la frecuencia de horquilla en pre- y post selección muestras utilizando la siguiente secuencia de generación, como reportero de reactivación confiere ventaja del crecimiento en la selección de higromicina B y dio lugar a enriquecimiento de horquillas responsables. Usando este acercamiento, identificado 30 genes implicados en MeCP2 silenciamiento y posteriormente confirmó los resultados de medir su actividad de luciferasa y transducción de las células de reportero con reguladores individuales.

<table>
	<tbody>
		<tr>
			<td>293FT Cell Line</td>
			<td>Invitrogen</td>
			<td>R700-07</td>
			<td></td>
		</tr>
		<tr>
			<td>5-Azacytidine</td>
			<td>Sigma</td>
			<td>A2385-100MG</td>
			<td></td>
		</tr>
		<tr>
			<td>Agencourt AMPure XP</td>
			<td>Beckman-Coulter</td>
			<td>A63881</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-MECP2 antibody</td>
			<td>Millipore</td>
			<td>07-013</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase</td>
			<td>Sigma</td>
			<td>C2674-1G</td>
			<td></td>
		</tr>
		<tr>
			<td>Corning 96-Well Solid White Polystyrene Microplates</td>
			<td>Fisher Scientific</td>
			<td>07-200-336</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s Modified Eagle Medium</td>
			<td>Gibco</td>
			<td>11965-092</td>
			<td></td>
		</tr>
		<tr>
			<td>Expression Arrest microRNA-adapted Retroviral Vector (pMSCV)</td>
			<td>Open Biosystems</td>
			<td>EAV4679</td>
			<td></td>
		</tr>
		<tr>
			<td>Expression Arrest pSM2 Retroviral shRNAmir library</td>
			<td>Open Biosystems</td>
			<td>RMM3796</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Fisherbrand</td>
			<td>03-600-511</td>
			<td></td>
		</tr>
		<tr>
			<td>HiSeq 2500</td>
			<td>Illumina</td>
			<td>SY&#8211;401&#8211;2501</td>
			<td>Or equivalent</td>
		</tr>
		<tr>
			<td>Hygromycin B</td>
			<td>Calbiochem</td>
			<td>400051-1MU</td>
			<td></td>
		</tr>
		<tr>
			<td>Lipofectamine 2000</td>
			<td>Invitrogen</td>
			<td>11668-019</td>
			<td></td>
		</tr>
		<tr>
			<td>Bright-Glo Luciferase Assay System</td>
			<td>Promega</td>
			<td>E2610</td>
			<td>Homogenous Assay for Screening Colonies</td>
		</tr>
		<tr>
			<td>Luciferase Assay System</td>
			<td>Promega</td>
			<td>E4530</td>
			<td>Non-Homogenous Assay for Testing Individual Hairpins</td>
		</tr>
		<tr>
			<td>Luminometer TopCount NXT</td>
			<td>Perkin Elmer</td>
			<td>N/A</td>
			<td>Or similar luminometer</td>
		</tr>
		<tr>
			<td>MiSeq Reagent Kit v2</td>
			<td>Illumina</td>
			<td>MS-102-2001</td>
			<td>Use kit compatible with your equipment</td>
		</tr>
		<tr>
			<td>Opti-MEM</td>
			<td>Gibco</td>
			<td>31985-070</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>pMD2.G</td>
			<td>Addgene</td>
			<td>#12259</td>
			<td>VSV-G envelope vector</td>
		</tr>
		<tr>
			<td>Polybrene</td>
			<td>Sigma</td>
			<td>TR-1003-G</td>
			<td></td>
		</tr>
		<tr>
			<td>Polyethylenimine</td>
			<td>Polysciences</td>
			<td>23966-1</td>
			<td></td>
		</tr>
		<tr>
			<td>psPAX2</td>
			<td>Addgene</td>
			<td>#12260</td>
			<td>Packaging vector</td>
		</tr>
		<tr>
			<td>Puromycin</td>
			<td>Gibco</td>
			<td>A11138-02</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin-EDTA (0.05%), phenol red</td>
			<td>Gibco</td>
			<td>25300-054</td>
			<td></td>
		</tr>
	</tbody>
</table>

pooled shrna screen for reactivation of mecp2 on the inactive x chromosome

Avance genéticos pantallas usando genes del reportero insertados en la heterocromatina se han utilizado para investigar los mecanismos de control epigenético en organismos modelo. Tecnologías incluyendo horquilla corta RNAs (shRNAs) y agrupadas regularmente otro corto palindrómico repeticiones (CRISPR) han permitido que tales pantallas en células de mamíferos diploides. Aquí describimos una pantalla shRNA a gran escala de los reguladores de la inactivación del X-cromosoma (XCI), utilizando una línea celular murina con luciferasa de luciérnaga y genes de resistencia a Higromicina golpeó en el c-término de la proteína de unión a CpG de metilo 2 (MeCP2) gene en el cromosoma x inactivo (Xi). Reactivación de la construcción en la línea celular de reportero confiere ventaja de supervivencia en selección de higromicina B, lo que nos permite una biblioteca grande de shRNA y identificar reguladores que reactivaron el reportero midiendo su selección posterior enriquecimiento utilizando secuenciación de próxima generación. Las horquillas enriquecidas entonces fueron validadas individualmente por prueba de su capacidad para activar el reportero de luciferasa en Xi.

Fibroblastos de ratón del tendón se cosecharon de descrita X /XMeCP2-LUC-HRratón hembra deMeCP2 , inmortalizado por transducción retroviral de oncogenes E6 y E7 de HPV-16 virus7, clonado usando dilución limitante y probados para actividad de luciferasa y expresión del salvaje-tipo proteína MeCP2 (figura 1A y 1B). Actividad de luciferasa fue robusto si el reportero estaba en Xa e imperceptibles si en Xi; la expresión nativa de MeCP2 exhibieron un...

Watch this Scientific Journal Video about Pooled shRNA Screen for Reactivation of MeCP2 on the Inactive X Chromosome at JoVE.com

Pooled shRNA Screen for Reactivation of MeCP2 on the Inactive X Chromosome

ShRNAs combinados pantalla para reactivación de MeCP2 en el cromosoma de X inactivo

Divulgamos una pequeña horquilla RNA (shRNA) y el siguiente protocolo basado en la secuencia de generación para la identificación de reguladores de la inactivación del cromosoma x en una línea celular murina con luciferasa de luciérnaga y genes de resistencia a Higromicina fusionado a la metil CpG Unión proteína 2 ( MeCP2) gen en el cromosoma X inactivo.

Forward genetic screens using reporter genes inserted into the heterochromatin have been extensively used to investigate mechanisms of epigenetic control ...

Begin this procedure with preparation of mouse tendon fibroblasts, as described in the text protocol. Harvest the cells from a 10-centimeter plate by first aspirating the media. Then add one milliliter of 0.05%trypsin EDTA and incubate for two to five minutes at 37-degrees Celsius.Following incubation, quench the trypsin with nine milliliters of DMEM-10, and collect the resuspended cells in a 15-milliliter conical tube. Dilute the cells with DMEM-10 to a final concentration of one cell per 100 microliters. Then transfer the cells to 96 well plates by pipetting 100 microliters of the suspension into each well.Incubate the cells at 37 degrees Celsius until the wells are confluent, which can take up to two to three weeks. Replace the media with fresh DMEM-10 every three to five days. When confluent, mobilize the cells with 20 microliters 0.05%trypsin EDTA per well, and split them into two duplicate sets of 96 well plates.Assay for luciferase activity in one set of plates. Use a homogenous Firefly luciferase assay that does not require media removal, following the protocol included with the luciferase assay kit. Use the assay results to select clones with no detectable luciferase activity from the remaining set of plates.Expand these clones first to a 24 well plate, and then to a six well plate. Perform the same for a clone with the highest luciferase activity. This will be used as a positive control for validation purposes.Following expansion in the six well plate, harvest an aliquot of each well for a Western blot. Mobilize the cells with 200 microliters of 0.05%trypsin EDTA. Incubate the cells for two to five minutes at 37 degrees Celsius.Quench the cells with two milliliters of DMEM-10, and transfer half of the cells to another six well plate. Wait until the cells attach to the bottom of the plate. Then wash the cells once with PBS before the lysing for the Western blot.Plate several negative clones at 0.2 million cells per well in a six well plate. Treat the cells once with 10 micromolar 5-azacytidine. Then incubate for 72 hours without changing the media before assaying for luciferase activity, as before.Next, choose one negative clone that gained luciferase activity with 5-azacytidine for the screen, and begin expanding it to multiple 10-centimeter plates. Freeze the remaining negative clones in liquid nitrogen as a backup. The positive clone can be maintained in the tissue culture or frozen until further use.In the morning, plate one million inactive X cells onto 10-centimeter tissue culture plates. In the afternoon, infect the plates by replacing the media with fresh DMEM-10 containing a predetermined amount of viral supernatant and five to 10 micrograms per milliliter of polybrene. After 18 to 24 hours, aspirate the media and add 10 milliliters of fresh DMEM-10 to each plate.Culture plates for another 48 hours. In the morning, mobilize the cells using one milliliter of 0.05%trypsin EDTA per plate, and quench the cells with 9 milliliters of DMEM-10 per plate. Run the suspension through a 100-micron mesh filter.Pull the filtered suspensions together, and seed two sets of 10-centimeter plates at one million cells per plate. In the afternoon, replace the media in one set of plates with DMEM-10 containing 15 micrograms per milliliter of Hygromycin B.In the other set, replace the media with fresh DMEM-10 only. After 48 hours, mobilize the cells from Hygromycin B untreated plates using one milliliter of 0.05%trypsin EDTA.Incubate for two to five minutes at 37 degrees Celsius. Next, quench the cells with 9 milliliters of DMEM-10. Pull the individual samples, and proceed immediately with extracting DNA.Continue culturing the Hygromycin B selection set for six more days, replenishing the selection media with fresh DMEM-10 containing Hygromycin B every other day. On day six, replace the selection media with fresh DMEM-10 only. Allow four days for recovery, and then harvest the post-selection sample DNA as before.Proceed to identify hairpins enriched in the post-selection samples, as described in the text protocol. To validate the hits, first seed eight million 293-FT cells per plate on 10-centimeter plates. The following day, replace the media with nine milliliters of antibiotic-free DMEM-10 per plate 30 minutes before transection.Next, add 0.5 milliliters of transfection mix one to each aliquot of transfection mix two, and gently mix by pipetting. Then incubate the mixture at room temperature for 20 minutes. Apply the mixture onto each plate in a drop-wise fashion, and swirl the plate gently to mix.The following day, replace the media with five milliliters of fresh DMEM-10.48 hours after initial transfection, collect the lentiviral supernatant, and run it through a 0.22-micron filter that has been prewet with DMEM-10 to maximize recovery. The next morning, plate 0.1 million inactive X cells per well onto six well plates. In the afternoon, infect the plates by replacing the media with two milliliters of fresh DMEM-10 containing lentiviral supernatant and five to 10 micrograms per milliliter of polybrene.Infect a control well with viral supernatant produced from an empty lentiviral vector. The following day, replace the media with two milliliters of DMEM-10 containing one milligram per milliliter of puromycin. Use selecting for four days.After four days, replace the media with two milliliters of fresh DMEM-10, and allow 48 to 72 hours for recovery. After mobilizing the cells with 150 microliters of 0.05%trypsin EDTA, incubate them for two to five minutes at 37 degrees Celsius. Quench the cells with 1.5 milliliters of DMEM-10 before transferring to conical tubes and centrifuging the cells at room temperature at 500 times G for 10 minutes.Remove the media and resuspended the cells in 100 microliters of lysis buffer provided in the luciferase assay kit. Incubate the suspension at room temperature for five minutes. After five minutes, transfer the suspension to a white 96 well plate.Perform the assay in the darkroom, following the protocol included in the kit. Use active X cells as a positive control and negative X cells infected with an empty lentiviral vector as a negative control. Immortalized mouse tendon fibroblast clones show either positive or negative Firefly luciferase activity, consistent with the placement of the reporter on the active or inactive X chromosome, respectively.MeCP2 expression, as determined by the Western blot, exhibits the reciprocal pattern. Note that Firefly luciferase activity can be induced in negative clones with administration of 5-azacitidine. If present on the active X chromosome, the Hygromycin resistance gene confers a survival advantage under Hygromycin selection, when compared to the cells with the gene on the inactive X chromosome.After watching this video, you should have a good understanding of how to design and perform a screen for regulators of X-chromosome inactivation using reporters selectively inserted on inactive X chromosome. My laboratory has previously carried out reported base screens for chromatin regulators in yeast, and our success with this approach inspired me to design this screen for regulators of X-chromosome inactivation in mammalian cells. Following this procedure, other methods, such as using small, interfering RNAs, CRISPR, small molecules can be performed to help answer additional questions regarding X-chromosome inactivation in mammalian cells.

Research

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Genetics

Conjugative Mating Assays for Sequence-specific Analysis of Transfer Proteins Involved in Bacterial Conjugation

Conjugación de apareamiento Los ensayos para el análisis específico de la secuencia de proteínas de transferencia que participan en la conjugación bacteriana

The transfer of genetic material by bacterial conjugation is a process that takes place via complexes formed by specific transfer proteins. In Escherichia ...

Investigación

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High-throughput Identification of Gene Regulatory Sequences Using Next-generation Sequencing of Circular Chromosome Conformation Capture (4C-seq)

High-throughput Identification of Gene Regulatory Sequences Using Next-generation Sequencing of Circular Chromosome Conformation Capture 4C-seq

Captura de alto rendimiento identificación de secuencias reguladoras de genes utilizando secuenciación de próxima generación de conformación Circular cromosoma (4C-seq)

The identification of regulatory elements for a given target gene poses a significant technical challenge owing to the variability in the positioning and ...

A Deep-sequencing-assisted, Spontaneous Suppressor Screen in the Fission Yeast Schizosaccharomyces pombe

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Una pantalla de supresor asistida por secuenciación profunda, espontánea en la levadura de fisión Schizosaccharomyces pombe

A genetic screen for mutant alleles that suppress phenotypic defects caused by a mutation is a powerful approach to identify genes that belong to closely ...

A Non-random Mouse Model for Pharmacological Reactivation of Mecp2 on the Inactive X Chromosome

Un modelo de ratón no aleatorio para la reactivación farmacológica de Mecp2 en el cromosoma X inactivo

X chromosome inactivation (XCI) is the random silencing of one X chromosome in females to achieve gene dosage balance between the sexes. As a result, all ...

Mass Spectrometry-Based Proteomics Analyses Using the OpenProt Database to Unveil Novel Proteins Translated from Non-Canonical Open Reading Frames

Análisis de proteómica basada en espectrometría de masa usando la base de datos OpenProt para develar nuevas proteínas traducción de marcos de lectura abierto no-canónico

Genome annotation is central to today's proteomic research as it draws the outlines of the proteomic landscape. Traditional models of open reading frame ...

Pooled CRISPR-Based Genetic Screens in Mammalian Cells

Pantallas genéticas basadas en CRISPR en células de mamíferos

Genome editing using the CRISPR-Cas system has vastly advanced the ability to precisely edit the genomes of various organisms. In the context of mammalian ...

A Screening Method for Identification of Heterochromatin-Promoting Drugs Using Drosophila

A Screening Method for Identification of Heterochromatin-Promoting Drugs Using Drosophila

Un método de detección para la identificación de medicamentos que promueven la heterocromatina utilizando Drosophila

Drosophila is an excellent model organism that can be used to screen compounds that might be useful for cancer therapy. The method described here is a ...

Identification of Enhancer-Promoter Contacts in Embryoid Bodies by Quantitative Chromosome Conformation Capture (4C)

Identification of Enhancer-Promoter Contacts in Embryoid Bodies by Quantitative Chromosome Conformation Capture 4C

Identificación de contactos potenciadores-promotores en cuerpos embrionarios por captura cuantitativa de conformación cromosómica (4C)

During mammalian development, cell fates are determined through the establishment of regulatory networks that define the specificity, timing, and spatial ...

A Suppressor Screen for the Characterization of Genetic Links Regulating Chronological Lifespan in Saccharomyces cerevisiae

A Suppressor Screen for the Characterization of Genetic Links Regulating Chronological Lifespan in Saccharomyces cerevisiae

Una pantalla supresora para la caracterización de los vínculos genéticos que regulan la vida cronológica en Saccharomyces cerevisiae

Aging is the time dependent deterioration of an organism&#8217;s normal biological processes that increases the probability of death. Many genetic factors ...

Application of DNA Fingerprinting using the D1S80 Locus in Lab Classes

Application of DNA Fingerprinting using the D1S80 Locus in Lab Classes

Aplicación de huellas dactilares de ADN utilizando el locus D1S80 en clases de laboratorio

In biological sciences, DNA fingerprinting has been widely used for paternity testing, forensic applications and phylogenetic studies. Here, we describe a ...