Name: genome-wide analysis of histone modifications distribution using the chromatin immunoprecipitation sequencing method in magnaporthe oryzae
Uploaded: 2021-06-02T14:00:00
Description: Watch this Scientific Journal Video about Genome-wide Analysis of Histone Modifications Distribution using the Chromatin Immunoprecipitation Sequencing Method in Magnaporthe oryzae at JoVE.com

This work was supported by National Natural Science Foundation of China (Grant no. 31871638), the Special Scientific Research Project of Beijing Agriculture University (YQ201603), the Scientific Project of Beijing Educational Committee (KM201610020005), the High-level scientific research cultivation project of BUA (GJB2021005).

1. Preparation of protoplasts from M. oryzae
<ol>
	<li>Prepare the oatmeal-tomato agar (OTA).
	<ol>
		<li>Weigh 30-50 g of oatmeal and boil it in 800 mL of water (ddH2O) for 20 min. Filter through two layers of gauze and take the filtrate.</li>
		<li>Pick ripe tomatoes and peel them. Squeeze the juice, and filter through two layers of gauze to collect 150 mL of the filtered juice.</li>
		<li>Mix all the tomato juice and the prepared oat filtrate thoroughly and add ddH2O up to 1000 mL.</li...

<ol>
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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=Covalent+modifications+of+histones+during+development+and+disease+pathogenesis.">Covalent modifications of histones during development and disease pathogenesis.</a> Nature Structural and Molecular Biology. 14 (11), 1008-1016 (2007).</li><li>Shilatifard, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+implementation+and+physiological+roles+for+histone+H3+lysine+4+(H3K4)+methylation.">Molecular implementation and physiological roles for histone H3 lysine 4 (H3K4) methylation.</a> Current Opinion in Cell Biology. 20 (3), 341-348 (2008).</li><li>Berger, S. 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E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alteration+of+nucleosome+structure+as+a+mechanism+of+transcriptional+regulation.">Alteration of nucleosome structure as a mechanism of transcriptional regulation.</a> Annual Review of Biochemistry. 67 (1), 545-579 (2003).</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>Akhtar, J., More, P., Albrecht, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ChIP-Seq+from+limited+starting+material+of+K562+cells+and+Drosophila+neuroblasts+using+tagmentation+assisted+fragmentation+approach.">ChIP-Seq from limited starting material of K562 cells and Drosophila neuroblasts using tagmentation assisted fragmentation approach.</a> Bio-protocol. 10 (4), 3520 (2020).</li><li>Steinhauser, S., Kurzawa, N., Eils, R., Herrmann, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comprehensive+comparison+of+tools+of+differential+ChIP-seq+analysis.">A comprehensive comparison of tools of differential ChIP-seq analysis.</a> Briefings in Bioinformatics. 17 (6), 953-966 (2016).</li><li>Kieu, 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=MoSET1+(histone+H3K4+methyltransferase+in+Magnaporthe+oryzae)+regulates+global+gene+expression+during+infection-related+morphogenesis.">MoSET1 (histone H3K4 methyltransferase in Magnaporthe oryzae) regulates global gene expression during infection-related morphogenesis.</a> Plos Genetics. 11 (7), 11005385 (2015).</li><li>Vu, B. V., Pham, K. T., Nakayashiki, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Substrate-induced+transcriptional+activation+of+the+MoCel7C+cellulase+gene+is+associated+with+methylation+of+histone+H3+at+lysine+4+in+the+rice+blast+fungus+Magnaporthe+oryzae.">Substrate-induced transcriptional activation of the MoCel7C cellulase gene is associated with methylation of histone H3 at lysine 4 in the rice blast fungus Magnaporthe oryzae.</a> Applied and Environmental Microbiology. 79 (21), 6823-6832 (2013).</li><li>Kazan, K., Gardiner, D. M., Manners, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+trail+of+a+cereal+killer:+recent+advances+in+Fusarium+graminearum+pathogenomics+and+host+resistance.">On the trail of a cereal killer: recent advances in Fusarium graminearum pathogenomics and host resistance.</a> Molecular Plant Pathology. 13 (4), 399-413 (2012).</li><li>Wang, G. H., 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+AMT1+arginine+methyltransferase+gene+is+important+for+plant+infection+and+normal+hyphal+growth+in+Fusarium+graminearum.">The AMT1 arginine methyltransferase gene is important for plant infection and normal hyphal growth in Fusarium graminearum.</a> PLoS One. 7 (5), 38324 (2012).</li><li>Liu, Y., 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+H3K4+methylation+regulates+hyphal+growth,+secondary+metabolism+and+multiple+stress+responses+in+Fusarium+graminearum.">Histone H3K4 methylation regulates hyphal growth, secondary metabolism and multiple stress responses in Fusarium graminearum.</a> Environmental Microbiology. 17 (11), 4615-4630 (2016).</li><li>Zhang, M. Y., 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+plant+infection+test:+spray+and+wound-mediated+inoculation+with+the+plant+pathogen+Magnaporthe+grisea.">The plant infection test: spray and wound-mediated inoculation with the plant pathogen Magnaporthe grisea.</a> Journal of Visualized Experiments. (138), e57675 (2018).</li><li>Connolly, L. R., Smith, K. M., Freitag, 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+Fusarium+graminearum+histone+H3K27+methyltransferase+KMT6+regulates+development+and+expression+of+secondary+metabolite+gene+clusters.">The Fusarium graminearum histone H3K27 methyltransferase KMT6 regulates development and expression of secondary metabolite gene clusters.</a> PloS Genetics. 9 (10), 1003916 (2013).</li><li>Palmer, J. 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=Loss+of+CclA,+required+for+histone+3+lysine+4+methylation,+decreases+growth+but+increases+secondary+metabolite+production+in+Aspergillus+fumigatus.">Loss of CclA, required for histone 3 lysine 4 methylation, decreases growth but increases secondary metabolite production in Aspergillus fumigatus.</a> PeerJ. 1, 4 (2013).</li><li>Ding, S. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Tig1+histone+deacetylase+complex+regulates+infectious+growth+in+the+rice+blast+fungus+Magnaporthe+oryzae.">The Tig1 histone deacetylase complex regulates infectious growth in the rice blast fungus Magnaporthe oryzae.</a> The Plant Cell. 22 (7), 2495-2508 (2010).</li><li>Dean, R. 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+genome+sequence+of+the+rice+blast+fungus+Magnaporthe+grisea.">The genome sequence of the rice blast fungus Magnaporthe grisea.</a> Nature. 434 (7036), 980-986 (2005).</li><li>Allis, C. 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=New+nomenclature+for+chromatin-modifying+enzymes.">New nomenclature for chromatin-modifying enzymes.</a> Cell. 131 (4), 633-636 (2007).</li><li>Shilatifard, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+COMPASS+family+of+histone+H3K4+methylases:+mechanisms+of+regulation+in+development+and+disease+pathogenesis.">The COMPASS family of histone H3K4 methylases: mechanisms of regulation in development and disease pathogenesis.</a> Annual Review of Biochemistry. 81, 65-95 (2012).</li><li>Zhou, S. 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Recently, ChIP-seq has become a widely used genomic analysis method for determining the binding sites of TFs or enrichment sites modified by specific histones. Compared to previous ChIP-seq technology, new ChIP-seq technology is highly sensitive and flexible. Results are provided in high resolution without negative effects, such as the noise signal caused by the non-specific hybridization of nucleic acids. Although this is a common gene expression analysis, many computational methods have been validated, and the complexi...

Epigenetics is a branch of genetic research that refers to the heritable change of gene expression without changing the nucleotide sequence of genes. An increasing number of studies have shown that epigenetic regulation plays an important role in the growth and development of eukaryotic cells, including chromatin that regulates and affects gene expression through the dynamic process of folding and assembly into higher-order structures1,2. Chromatin remodeling and covalent histone modification affect and regulate the function and structure of chromatin through the variation of chromatin polymers, thereby achieving the function of regulating gene expression3,4,5,6. Posttranslational modifications of histone include acetylation, phosphorylation, methylation, monoubiquitination, sumoylation, and ADP ribosylation7,8,9. Histone H3K4 methylation, particularly trimethylation, has been mapped to transcription start sites where it is associated with transcription replication, recombination, repair, and RNA processing in eukaryotes10,11.
ChIP-seq technology was introduced in 2007 and has become the experimental standard for the genome-wide analysis of transcriptional regulation and epigenetic mechanisms12,13. This method is suitable at the genome-wide scale and for obtaining histone or transcription factor interaction information, including DNA segments of DNA binding proteins. Any DNA sequences crosslinked to proteins of interest will coprecipitate as a part of the chromatin complex. New-generation sequencing techniques are also used to sequence 36-100 bp of DNA, which are then matched to the corresponding target genome.
In phytopathogenic fungi, research has recently begun to study how histone methylation modifications regulate their target genes in the process of pathogenicity. Some previous studies proved that the regulation of histone methylase-related genes is mainly reflected in gene silencing and catalyzing the production of Secondary Metabolites (SM). MoSet1 is the H3K4 methylase in M. oryzae. Knockout of this gene results in the complete deletion of H3K4me3 modification14. Compared with the wild-type strain, the expression of the gene MoCEL7C in the mutant is inhibited in the CMC-induced state and in the non-induced state (glucose or cellobiose), the expression of MoCEL7C increased15. In Fusarium graminearum, KMT6 can catalyze the methylation modification of H3K27me3, regulate the normal development of fungi, and help regulate the &#34;cryptic genome&#34; containing the SM gene cluster16,17,18,19. In 2013, Connolly reported that H3K9 and H3K27 methylation regulates the pathogenic process of fungi through secondary metabolites and effector factors that regulate the inhibition of target genes20. In Aspergillus, the modification of histones H3K4me2 and H3K4me3 is related to gene activation and plays an important role in controlling the chromatin level regulation of SM gene clusters21. In M. oryzae, Tig1 (homologous to Tig1 in yeast and mammals) is an HADC (histone deacetylase)22. Knockout of the Tig1 gene leads to the complete loss of pathogenicity and spore production ability in the null mutant. It is more sensitive to a peroxygen environment, which cannot produce infective hyphae22.
The rice blast caused by M. oryzae. is one of the most serious rice diseases in most rice-growing areas in the world19. Due to its representative infection process, M. oryzae is similar to the infection process of many important pathogenic fungi. As it can easily carry out molecular genetic operations, the fungus has become a model organism for studying fungal-plant interactions23. Blocking every step of the infection process of M. oryzae may result in unsuccessful infection. The morphological changes during the infection process are strictly regulated by the entire genome function and gene transcription. Among them, epigenetic modifications such as histone methylation play an essential role in the transcriptional regulation of functional genes24,25. However, so far, few studies have been done on the molecular mechanism of epigenetic modifications such as histone methylation and histone acetylation in the transcription of pathogenesis genes in M. oryzae. Therefore, further developing the epigenetic regulation mechanism of the rice blast fungus while researchinh the upstream and downstream regulatory network of these pathogenic related genes will help develop rice blast prevention and control strategies.
With the development of functional genomics such as ChIP-seq, especially in epigenetics, this high-throughput data acquisition method has accelerated research on chromosomes. Using the ChIP-seq experimental technology, the genome-wide distribution of histone methylation (such as H3K4me3, H3K27me3, H3K9me3) in M. oryzae and other filamentous fungi can be identified. Therefore, this method can help elucidate the molecular mechanisms underlying how epigenetic modifications regulate their candidate target genes during fungal pathogenesis in plant pathology.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>acidic casein hydrolysate</td>
			<td>WAKO</td>
			<td>65072-00-6</td>
			<td>Medium configuration</td>
		</tr>
		<tr>
			<td>agar powder</td>
			<td>scientan</td>
			<td>9002-18-0</td>
			<td>Medium configuration</td>
		</tr>
		<tr>
			<td>deoxycholic acid</td>
			<td>MedChemExpress</td>
			<td>83-44-3</td>
			<td>protein and dissolution</td>
		</tr>
		<tr>
			<td>DNA End-Repair kit</td>
			<td>NovoBiotec</td>
			<td>ER81050</td>
			<td>Repair DNA or cDNA damaged by enzymatic or mechanical shearing</td>
		</tr>
		<tr>
			<td>Dynabeads</td>
			<td>Invitrogen</td>
			<td>no.100.02D</td>
			<td>Binding target</td>
		</tr>
		<tr>
			<td>EB buffer</td>
			<td>JIMEI</td>
			<td>JC2174</td>
			<td>Membrane and liquid</td>
		</tr>
		<tr>
			<td>EDTA</td>
			<td>ThermoFisher</td>
			<td>AM9912</td>
			<td>protease inhibitor</td>
		</tr>
		<tr>
			<td>enzymatic casein hydrolysate</td>
			<td>Sigma</td>
			<td>91079-40-2</td>
			<td>Medium configuration</td>
		</tr>
		<tr>
			<td>glucose</td>
			<td>Sigma</td>
			<td>50-99-7</td>
			<td>Medium configuration</td>
		</tr>
		<tr>
			<td>glycogen</td>
			<td>ThermoFisher</td>
			<td>AM9510</td>
			<td>Precipitant action</td>
		</tr>
		<tr>
			<td>H3K4me3 antibodies</td>
			<td>Abcam</td>
			<td>ab8580</td>
			<td>Immune response to H3K4me3 protein</td>
		</tr>
		<tr>
			<td>illumina Genome Analyzer</td>
			<td>illumina</td>
			<td>illumina Hiseq 2000</td>
			<td>Large configuration</td>
		</tr>
		<tr>
			<td>Illumina PCR primers</td>
			<td>illumina</td>
			<td>CleanPlex</td>
			<td>Random universal primer</td>
		</tr>
		<tr>
			<td>isoamyl alcohol</td>
			<td>chemical book</td>
			<td>30899-19-5</td>
			<td>Purified DNA</td>
		</tr>
		<tr>
			<td>LiCl</td>
			<td>ThermoFisher</td>
			<td>AM9480</td>
			<td>specific removal RNA</td>
		</tr>
		<tr>
			<td>lysing enzymes</td>
			<td>Sigma</td>
			<td>L1412-10G</td>
			<td>cell lysis buffer</td>
		</tr>
		<tr>
			<td>Mouse IgG</td>
			<td>Yeasen</td>
			<td>36111ES10</td>
			<td>Animal normal immunoglobulin</td>
		</tr>
		<tr>
			<td>NaCl solution</td>
			<td>ThermoFisher</td>
			<td>7647-14-5</td>
			<td>Medium configuration</td>
		</tr>
		<tr>
			<td>NaHCO3</td>
			<td>Seebio</td>
			<td>SH30173.08*</td>
			<td>preparation of protein complex eluent</td>
		</tr>
		<tr>
			<td>NP-40</td>
			<td>ThermoFisher</td>
			<td>85124</td>
			<td>cell lysate to promote cell lysis</td>
		</tr>
		<tr>
			<td>PCR Purification kit</td>
			<td>Qiagen</td>
			<td>28004</td>
			<td>The purification procedure removes primers from DNA samples</td>
		</tr>
		<tr>
			<td>protease inhibitors</td>
			<td>ThermoFisher</td>
			<td>A32965</td>
			<td>A protein inhibitor that decreases protein activity</td>
		</tr>
		<tr>
			<td>Proteinase K</td>
			<td>ThermoFisher</td>
			<td>AM2546</td>
			<td>DNA Extraction Reagent</td>
		</tr>
		<tr>
			<td>Qubit 4.0</td>
			<td>ThermoFisher</td>
			<td>Q33226</td>
			<td>Medium configuration</td>
		</tr>
		<tr>
			<td>RIPA buffer</td>
			<td>ThermoFisher</td>
			<td>9806S</td>
			<td>cell lysis buffer</td>
		</tr>
		<tr>
			<td>RNase A</td>
			<td>ThermoFisher</td>
			<td>AM2271</td>
			<td>Purified DNA</td>
		</tr>
		<tr>
			<td>SDS</td>
			<td>ThermoFisher</td>
			<td>AM9820</td>
			<td>cover up the charge differences</td>
		</tr>
		<tr>
			<td>sodium acetate solution</td>
			<td>ThermoFisher</td>
			<td>R1181</td>
			<td>Acetic acid buffer</td>
		</tr>
		<tr>
			<td>sodium deoxycholate</td>
			<td>ThermoFisher</td>
			<td>89904</td>
			<td>inhibition of protease degradation</td>
		</tr>
		<tr>
			<td>T4 DNA ligase</td>
			<td>ThermoFisher</td>
			<td>EL0011</td>
			<td>Under the condition of ATP as coenzyme, DNA ligase</td>
		</tr>
		<tr>
			<td>T4 DNA ligase buffer</td>
			<td>ThermoFisher</td>
			<td>B69</td>
			<td>DNA ligase buffer</td>
		</tr>
		<tr>
			<td>Tris-HCl</td>
			<td>ThermoFisher</td>
			<td>1185-53-1</td>
			<td>buffer action</td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>ThermoFisher</td>
			<td>HFH10</td>
			<td>keep the membrane protein stable</td>
		</tr>
		<tr>
			<td>yeast extract</td>
			<td>OXOID</td>
			<td>LP0021</td>
			<td>Medium configuration</td>
		</tr>
	</tbody>
</table>

genome-wide analysis of histone modifications distribution using the chromatin immunoprecipitation sequencing method in magnaporthe oryzae

Chromatin immunoprecipitation sequencing (ChIP-seq) is a powerful and widely used molecular technique for mapping whole genome locations of transcription factors (TFs), chromatin regulators, and histone modifications, as well as detecting entire genomes for uncovering TF binding patterns and histone posttranslational modifications. Chromatin-modifying activities, such as histone methylation, are often recruited to specific gene regulatory sequences, causing localized changes in chromatin structures and resulting in specific transcriptional effects. The rice blast is a devastating fungal disease on rice throughout the world and is a model system for studying fungus-plant interaction. However, the molecular mechanisms in how the histone modifications regulate their virulence genes in Magnaporthe oryzae remain elusive. More researchers need to use ChIP-seq to study how histone epigenetic modification regulates their target genes. ChIP-seq is also widely used to study the interaction between protein and DNA in animals and plants, but it is less used in the field of plant pathology and has not been well developed. In this paper, we describe the experimental process and operation method of ChIP-seq to identify the genome-wide distribution of histone methylation (such as H3K4me3) that binds to the functional target genes in M. oryzae. Here, we present a protocol to analyze the genome-wide distribution of histone modifications, which can identify new target genes in the pathogenesis of M. oryzae and other filamentous fungi.

The whole flow chart of the ChIP-seq method is shown in Figure 1. ChIP-seq experiments were performed using antibodies against H3K4me3 in the wild-type strain P131 and three null mutant strains that were devoid of mobre2, mospp1, and moswd2 gene to verify the whole genome-wide profile of histone H3K4me3 distribution in M. oryzae. The protoplasts of the wild-type strain, &#916;mobre2, &#916;mospp1, and &#916;moswd2, were prepared ...

Watch this Scientific Journal Video about Genome-wide Analysis of Histone Modifications Distribution using the Chromatin Immunoprecipitation Sequencing Method in Magnaporthe oryzae at JoVE.com

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

Here, we present a protocol to analyze the genome-wide distribution of histone modifications, which can identify new target genes in the pathogenesis of M. oryzae and other filamentous fungi.

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

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

This method can help elucidate the molecular mechanisms underlying the regulation of candidate target genes via epigenetic modifications during fungal pathogenesis in plant pathology. Chromatin immunoprecipitation sequencing technology can efficiently detect DNA segments that interact with histones and transcription factors in the whole genome. Compared with other methods, it can improve efficiency and resolution.Begin by adding 100 microliters of liquid complete medium to the oatmeal tomato Agger plates using a 100 microliter pipette. Using an inoculation loop, scrape the mycelia of the wild type strain and the knockout strain. Collect the mycelia debris and transfer them to 250 milliliters of liquid complete medium.Wash the fungal hyphae with 500 milliliters of 0.7 molar sodium chloride solution. Then collect the fungal myceliUM and weigh it. Add approximately one milliliter of lysis enzyme permeation solution per one gram of the fungal mycelium.Place the hyphae for licing at 28 degrees Celsius for three to four hours with shaking at 150 RPM. Wash the liced hyphae with 50 milliliters of 0.7 molar sodium chloride solution. Centrifuge the sample and discard the supernatant carefully.Re-suspend the protoplast in 20 milliliters of 0.7 molar sodium chloride solution. Add 55 microliters of 37%formaldehyde drop by drop to two milliliters of sodium chloride buffer containing protoplasts for cross-linking until the final concentration is 1%To quench the unreacted formaldehyde, add 20 microliters of 10 times glycine to each tube. Discard the supernatant carefully after centrifugation.Re-suspend the pellet in one milliliter of 0.7 molar sodium chloride solution. Discard the supernatant carefully after centrifugation and re-suspend the pellet in 750 microliters of RIPA buffer. Add 37.5 microliters of 20 times protease inhibitor.Shear the chromatin by sonication for eight minutes using an ultrasonic homogenizer. After the sample has been ultrasonically broken, take out a part of the sample as input containing all DNA and protein released after the sample is sonicated. To analyze the length of the DNA fragments, run a 1%agarose gel electrophoresis after sonication.After centrifugation, transfer the centrifuged supernatant to a 1.5 milliliter centrifuge tube and store it at negative 80 degrees Celsius for later use. Before performing the IP experiment, dilute each chromatin sample to a ratio of one to 10 with one times RIPA buffer. Pipette 50 microliters of super paramagnetic protein beads into a two milliliter centrifuge tube.Place the tubes on a magnetic stand and let the magnetic beads precipitate. Then remove the supernatant. Add one milliliter of pre-cooled one times RIPA buffer to the tube and wash super paramagnetic protein beads three times.Place the tubes on a magnetic stand and remove the supernatant. Add 100 microliters of one times RIPA buffer to each tube. Add 30 microliters of the chromatin sample, 100 microliters of super paramagnetic protein beads and four microliters of H3K4me3 antibody to the tube, mixing them well.Place the samples on a rotary shaker to incubate them overnight at four degrees Celsius at 30 times G.Wash the super paramagnetic protein bead antibody and chromatin complex by resuspending the beads in one milliliter of one times RIPA buffer. Wash the sample with one milliliter of low salt immune complex wash buffer, then with one milliliter of high salt immune complex wash buffer. Rinse the beads with one milliliter of lithium chloride buffer and remove the supernatant.Then add one milliliter of TE buffer to the tube. Place the tube again with one milliliter of TE buffer and remove the supernatant with a pipette. Add 100 microliters of elution buffer to each centrifuge tube.Perform elution at 65 degrees Celsius for 15 minutes. Centrifuge for one minute at 10, 000 times G at four degrees Celsius and collect the supernatant into new centrifuge tubes. Add eight microliters of five molar sodium chloride to all the tubes and incubate at 65 degrees Celsius for four to five hours or overnight to reverse the DNA protein cross-links.Add one microliter of Rnase A and incubate for 30 minutes at 37 degrees Celsius. Add four microliters of proteinase K to each tube and incubate at 45 degrees Celsius for one to two hours. Add 550 microliters of the fenal chloroform and isoamyl alcohol mixture to the centrifuge tube.Centrifuge for 15 minutes at 10, 000 times G and aspirate the supernatant. Add 1/10 volume of three molar sodium acetate solution, 2.5 volumes of absolute ethanol and three microliters of glycogen to the tube. Place the sample in a refrigerator at negative 20 degrees Celsius overnight for precipitation.On the next day, centrifuge the tubes and discard the supernatant. Wash the pellet three times with one milliliter of freshly prepared 75%ethanol at 10, 000 times G.Add 50 microliters of sterile deionized water to sufficiently dissolve the precipitate. Repair the DNA ends to generate blunt ended DNA using a DNA end repair kit, and instructions mentioned in the text manuscript.To add adenine basis to the three prime ends, add 30 microliters of DNA, two microliters of water, five microliters of 10 times Taq buffer, 10 microliters of one millimolar dATP and three microliters of Taq DNA polymerase to a 0.2 microliter PCR centrifuge tube. Mix them and react in a PCR machine at 72 degrees Celsius for 10 minutes. Perform linker ligation by mixing 10 microliters of DNA, 9.9 microliters of water, 2.5 microliters of T4 DNA ligase buffer, 0.1 microliter of adapter oligo mix, and 2.5 microliters of T4 DNA ligase in a 0.2 microliter PCR centrifuge tube.Incubate the tube at 16 degrees Celsius for four hours. To amplify the DNA using PCR primers, add 10.5 microliters of DNA, 12.5 microliters of two times high fidelity master mix. one microliter of PCR primer PE 1.0 and one microliter of PCR primer PE 2.0 to a 0.2 microliter PCR centrifuge tube and mix well.The H3K4me3 signals of the mobre2, mospp1 and moswd2 deletion mutants were significantly decreased at its functional target regions. Compared to the wild type strain P131, the signals of enriched H3K4me3 chromatin immunoprecipitation sequencing reads in the mobre2, mospp1 and moswd2 deletion mutants were largely decreased. Following this procedure, chip on chip and chip qPCR can be performed.They are generally used to screen the downstream target gene of a protein and study protein DNA interactions at known genome binding sites.

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Unit 1

Structure and Organization of DNA

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Genome-wide Determination of Mammalian Replication Timing by DNA Content Measurement

Replication of the genome occurs during S phase of the cell cycle in a highly regulated process that ensures the fidelity of DNA duplication. Each genomic region is replicated at a distinct time during S phase through the simultaneous activation of multiple origins of replication. Time of replication (ToR) correlates with many genomic and epigenetic features and is linked to mutation rates and cancer. Comprehending the full genomic view of the replication program, in health and disease is a major future goal and challenge.
This article describes in detail the &#34;Copy Number Ratio of S/G1 for mapping genomic Time of Replication&#34; method (herein called: CNR-ToR), a simple approach to map the genome wide ToR of mammalian cells. The method is based on the copy number differences between S phase cells and G1 phase cells. The CNR-ToR method is performed in 6 steps: 1. Preparation of cells and staining with propidium iodide (PI); 2. Sorting G1 and S phase cells using fluorescence-activated cell sorting (FACS); 3. DNA purification; 4. Sonication; 5. Library preparation and sequencing; and 6. Bioinformatic analysis. The CNR-ToR method is a fast and easy approach that results in detailed replication maps.

We describe here a relatively fast and simple approach for mapping genome-wide mammalian replication timing, from cell isolation to the basic analysis of the sequencing results. A genomic map of a representative replication program will be provided following the protocol.

Replication of the genome occurs during S phase of the cell cycle in a highly regulated process that ensures the fidelity of DNA duplication. Each genomic ...

Analysis of the c-KIT Ligand Promoter Using Chromatin Immunoprecipitation

Multiple cellular processes, including DNA replication and repair, DNA recombination, and gene expression, require interactions between proteins and DNA. Therefore, DNA-protein interactions regulate multiple physiological, pathophysiological, and biological functions, such as cell differentiation, cell proliferation, cell cycle control, chromosome stability, epigenetic gene regulation, and cell transformation. In eukaryotic cells, the DNA interacts with histone and nonhistone proteins and is condensed into chromatin. Several technical tools can be used to analyze DNA-protein interactions, such as the Electrophoresis (gel) Mobility Shift Assay (EMSA) and DNase I footprinting. However, these techniques analyze the protein-DNA interaction in vitro, not within the cellular context. Chromatin immunoprecipitation (ChIP) is a technique that captures proteins at their specific DNA binding sites, thereby allowing for the identification of DNA-protein interactions within their chromatin context. It is done by fixation&#160;of the DNA-protein interaction, followed by&#160;immunoprecipitation of the protein of interest. Subsequently, the genomic site that the protein was bound to is characterized. Here, we describe and discuss ChIP and demonstrate its analytical value for the identification of the Transforming Growth Factor-&#946; (TGF-&#946;)-induced binding of the transcription factor SMAD2 to SMAD Binding Elements (SBE) within the promoter region of the tyrosine-protein kinase Kit (c-KIT) receptor ligand Stem Cell Factor (SCF).

DNA-protein interactions are essential for multiple biological processes. During the evaluation of cellular functions, the analysis of DNA-protein interactions is indispensable for understanding gene regulation. Chromatin immunoprecipitation (ChIP) is a powerful tool to analyze such interactions in vivo.

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

Signaling pathways regulate gene expression programs via the modulation of the chromatin structure at different levels, such as by post-translational modifications (PTMs) of histone tails, the exchange of canonical histones with histone variants, and nucleosome eviction. Such regulation requires the binding of signal-sensitive transcription factors (TFs) that recruit chromatin-modifying enzymes at regulatory elements defined as enhancers. Understanding how signaling cascades regulate enhancer activity requires a comprehensive analysis of the binding of TFs, chromatin modifying enzymes, and the occupancy of specific histone marks and histone variants. Chromatin immunoprecipitation (ChIP) assays utilize highly specific antibodies to immunoprecipitate specific protein/DNA complexes. The subsequent analysis of the purified DNA allows for the identification the region occupied by the protein recognized by the antibody. This work describes a protocol to efficiently perform ChIP of histone proteins in a mature mouse T-cell line. The presented protocol allows for the performance of ChIP assays in a reasonable timeframe and with high reproducibility.

Chromatin Immunoprecipitation ChIP in Mouse T-cell Lines

This work describes a protocol for chromatin immunoprecipitation (ChIP) using a mature mouse T-cell line. This protocol is suitable to investigate the distribution of specific histone marks at specific promoter sites or genome-wide.

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

We present a modified native chromatin immunoprecipitation sequencing (ChIP-seq) experimental protocol compatible with a Gaussian mixture distribution based analysis methodology (nucleosome density ChIP-seq; ndChIP-seq) that enables the generation of combined measurements of micrococcal nuclease (MNase) accessibility with histone modification genome-wide. Nucleosome position and local density, and the posttranslational modification of their histone subunits, act in concert to regulate local transcription states. Combinatorial measurements of nucleosome accessibility with histone modification generated by ndChIP-seq allows for the simultaneous interrogation of these features. The ndChIP-seq methodology is applicable to small numbers of primary cells inaccessible to cross-linking based ChIP-seq protocols. Taken together, ndChIP-seq enables the measurement of histone modification in combination with local nucleosome density to obtain new insights into shared mechanisms that regulate RNA transcription within rare primary cell populations.

We present a modified native chromatin immunoprecipitation sequencing (ChIP-seq) methodology for the generation of sequence datasets suitable for a nucleosome density ChIP-seq analytical framework integrating micrococcal nuclease (MNase) accessibility with histone modification measurements.

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

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

Chromatin immunoprecipitation (ChIP) is a widely-used technique for mapping the localization of post-translationally modified histones, histone variants, transcription factors, or chromatin-modifying enzymes at a given locus or on a genome-wide scale. The combination of ChIP assays with next-generation sequencing (i.e., ChIP-Seq) is a powerful approach to globally uncover gene regulatory networks and to improve the functional annotation of genomes, especially of non-coding regulatory sequences. ChIP protocols normally require large amounts of cellular material, thus precluding the applicability of this method to investigating rare cell types or small tissue biopsies. In order to make the ChIP assay compatible with the amount of biological material that can typically be obtained in vivo during early vertebrate embryogenesis, we describe here a simplified ChIP protocol in which the number of steps required to complete the assay were reduced to minimize sample loss. This ChIP protocol has been successfully used to investigate different histone modifications in various embryonic chicken and adult mouse tissues using low to medium cell numbers (5 x 104 - 5 x 105 cells). Importantly, this protocol is compatible with ChIP-seq technology using standard library preparation methods, thus providing global epigenomic maps in highly relevant embryonic tissues.

Chromatin Immunoprecipitation ChIP Protocol for Low-abundance Embryonic Samples

Here, we describe a chromatin immunoprecipitation (ChIP) and ChIP-seq library preparation protocol to generate global epigenomic profiles from low-abundance chicken embryonic samples.

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

Mapping Genome-wide Accessible Chromatin in Primary Human T Lymphocytes by ATAC-Seq

Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) is a method used for the identification of open (accessible) regions of chromatin. These regions represent regulatory DNA elements (e.g., promoters, enhancers, locus control regions, insulators) to which transcription factors bind. Mapping the accessible chromatin landscape is a powerful approach for uncovering active regulatory elements across the genome. This information serves as an unbiased approach for discovering the network of relevant transcription factors and mechanisms of chromatin structure that govern gene expression programs. ATAC-seq is a robust and sensitive alternative to DNase I hypersensitivity analysis coupled with next-generation sequencing (DNase-seq) and formaldehyde-assisted isolation of regulatory elements (FAIRE-seq) for genome-wide analysis of chromatin accessibility and to the sequencing of micrococcal nuclease-sensitive sites (MNase-seq) to determine nucleosome positioning. We present a detailed ATAC-seq protocol optimized for human primary immune cells i.e. CD4+ lymphocytes (T helper 1 (Th1) and Th2 cells). This comprehensive protocol begins with cell harvest, then describes the molecular procedure of chromatin tagmentation, sample preparation for next-generation sequencing, and also includes methods and considerations for the computational analyses used to interpret the results. Moreover, to save time and money, we introduced quality control measures to assess the ATAC-seq library prior to sequencing. Importantly, the principles presented in this protocol allow its adaptation to other human immune and non-immune primary cells and cell lines. These guidelines will also be useful for laboratories which are not proficient with next-generation sequencing methods.

Assay for Transposase-Accessible Chromatin coupled with high-throughput sequencing (ATAC-seq) is a genome-wide method to uncover accessible chromatin. This is a step-by-step ATAC-seq protocol, from molecular to the final computational analysis, optimized for human lymphocytes (Th1/Th2). This protocol can be adopted by researchers without prior experience in next-generation sequencing methods.

Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) is a method used for the identification of open (accessible) regions ...

Generation of Genome-wide Chromatin Conformation Capture Libraries from Tightly Staged Early Drosophila Embryos

Investigating the three-dimensional architecture of chromatin offers invaluable insight into the mechanisms of gene regulation. Here, we describe a protocol for performing the chromatin conformation capture technique in situ Hi-C on staged Drosophila melanogaster embryo populations. The result is a sequencing library that allows the mapping of all chromatin interactions that occur in the nucleus in a single experiment. Embryo sorting is done manually using a fluorescent stereo microscope and a transgenic fly line containing a nuclear marker. Using this technique, embryo populations from each nuclear division cycle, and with defined cell cycle status, can be obtained with very high purity. The protocol may also be adapted to sort older embryos beyond gastrulation. Sorted embryos are used as inputs for in situ Hi-C. All experiments, including sequencing library preparation, can be completed in five days. The protocol has low input requirements and works reliably using 20 blastoderm stage embryos as input material. The end result is a sequencing library for next generation sequencing. After sequencing, the data can be processed into genome-wide chromatin interaction maps that can be analyzed using a wide range of available tools to gain information about topologically associating domain (TAD) structure, chromatin loops, and chromatin compartments during Drosophila development.

Generation of Genome-wide Chromatin Conformation Capture Libraries from Tightly Staged Early Drosophila Embryos

This work describes a protocol for the generation of high resolution in situ Hi-C libraries from tightly staged pre-gastrulation Drosophila melanogaster embryos.

Investigating the three-dimensional architecture of chromatin offers invaluable insight into the mechanisms of gene regulation. Here, we describe a ...

Chromatin Immunoprecipitation (ChIP) of Histone Modifications from Saccharomyces cerevisiae

Histone post-translational modifications (PTMs), such as acetylation, methylation and phosphorylation, are dynamically regulated by a series of enzymes that add or remove these marks in response to signals received by the cell. These PTMS are key contributors to the regulation of processes such as gene expression control and DNA repair. Chromatin immunoprecipitation (chIP) has been an instrumental approach for dissecting the abundance and localization of many histone PTMs throughout the genome in response to diverse perturbations to the cell. Here, a versatile method for performing chIP of post-translationally modified histones from the budding yeast Saccharomyces cerevisiae (S. cerevisiae) is described. This method relies on crosslinking of proteins and DNA using formaldehyde treatment of yeast cultures, generation of yeast lysates by bead beating, solubilization of chromatin fragments by micrococcal nuclease, and immunoprecipitation of histone-DNA complexes. DNA associated with the histone mark of interest is purified and subjected to quantitative PCR analysis to evaluate its enrichment at multiple loci throughout the genome. Representative experiments probing the localization of the histone marks H3K4me2 and H4K16ac in wildtype and mutant yeast are discussed to demonstrate data analysis and interpretation. This method is suitable for a variety of histone PTMs and can be performed with different mutant strains or in the presence of diverse environmental stresses, making it an excellent tool for investigating changes in chromatin dynamics under different conditions.

Chromatin Immunoprecipitation ChIP of Histone Modifications from Saccharomyces cerevisiae

Here, we describe a protocol for chromatin immunoprecipitation of modified histones from the budding yeast Saccharomyces cerevisiae. Immunoprecipitated DNA is subsequently used for quantitative PCR to interrogate the abundance and localization of histone post-translational modifications throughout the genome.

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

Promoter Capture Hi-C: High-resolution, Genome-wide Profiling of Promoter Interactions

The three-dimensional organization of the genome is linked to its function. For example, regulatory elements such as transcriptional enhancers control the spatio-temporal expression of their target genes through physical contact, often bridging considerable (in some cases hundreds of kilobases) genomic distances and bypassing nearby genes. The human genome harbors an estimated one million enhancers, the vast majority of which have unknown gene targets. Assigning distal regulatory regions to their target genes is thus crucial to understand gene expression control. We developed Promoter Capture Hi-C (PCHi-C) to enable the genome-wide detection of distal promoter-interacting regions (PIRs), for all promoters in a single experiment. In PCHi-C, highly complex Hi-C libraries are specifically enriched for promoter sequences through in-solution hybrid selection with thousands of biotinylated RNA baits complementary to the ends of all promoter-containing restriction fragments. The aim is to then pull-down promoter sequences and their frequent interaction partners such as enhancers and other potential regulatory elements. After high-throughput paired-end sequencing, a statistical test is applied to each promoter-ligated restriction fragment to identify significant PIRs at the restriction fragment level. We have used PCHi-C to generate an atlas of long-range promoter interactions in dozens of human and mouse cell types. These promoter interactome maps have contributed to a greater understanding of mammalian gene expression control by assigning putative regulatory regions to their target genes and revealing preferential spatial promoter-promoter interaction networks. This information also has high relevance to understanding human genetic disease and the identification of potential disease genes, by linking non-coding disease-associated sequence variants in or near control sequences to their target genes.

DNA regulatory elements, such as enhancers, control gene expression by physically contacting target gene promoters, often through long-range chromosomal interactions spanning large genomic distances. Promoter Capture Hi-C (PCHi-C) identifies significant interactions between promoters and distal regions, enabling the assignment of potential regulatory sequences to their target genes.

The three-dimensional organization of the genome is linked to its function. For example, regulatory elements such as transcriptional enhancers control the ...

Chromatin Immunoprecipitation of Murine Brown Adipose Tissue

Most cellular processes are regulated by transcriptional modulation of specific gene programs. Such modulation is achieved through the combined actions of a wide range of transcription factors (TFs) and cofactors mediating transcriptional activation or repression via changes in chromatin structure. Chromatin immunoprecipitation (ChIP) is a useful molecular biology approach for mapping histone modifications and profiling transcription factors/cofactors binding to DNA, thus providing a snapshot of the dynamic nuclear changes occurring during different biological processes.
To study transcriptional regulation in adipose tissue, samples derived from in vitro cell cultures of immortalized or primary cell lines are often favored in ChIP assays because of the abundance of starting material and reduced biological variability. However, these models represent a limited snapshot of the actual chromatin state in living organisms. Thus, there is a critical need for optimized protocols to perform ChIP on adipose tissue samples derived from animal models.
Here we describe a protocol for efficient ChIP-seq of both histone modifications and non-histone proteins in brown adipose tissue (BAT) isolated from a mouse. The protocol is optimized for investigating genome-wide localization of proteins of interest and epigenetic markers in the BAT, which is a morphologically and physiologically distinct tissue amongst fat depots.

Here we describe a protocol for efficient chromatin immunoprecipitation (ChIP) followed by high-throughput DNA sequencing (ChIP-seq) of brown adipose tissue (BAT) isolated from a mouse. This protocol is suitable for both mapping histone modifications and investigating genome-wide localization of non-histone proteins of interest in vivo.

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