게시된 데이터와 귀중한 토론을 공유해 주신 Rhee 연구소의 회원에게 감사드립니다. 이 작품은 캐나다 자연 과학 및 공학 연구 위원회 (NSERC) RGPIN-2018-06404 (H.R.)에 의해 지원되었다.

<ol>
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F. <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+structure+and+organization+of+eukaryotic+pre-initiation+complexes.">Genome-wide structure and organization of eukaryotic pre-initiation complexes.</a> Nature. 483 (7389), 295-301 (2012).</li><li>Zhou, X. F., Yan, Q., Wang, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deciphering+the+regulon+of+a+GntR+family+regulator+via+transcriptome+and+ChIP-exo+analyses+and+its+contribution+to+virulence+in+Xanthomonas+citri.">Deciphering the regulon of a GntR family regulator via transcriptome and ChIP-exo analyses and its contribution to virulence in Xanthomonas citri.</a> Molecular Plant Pathology. 18 (2), 249-262 (2017).</li><li>Kim, 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=Systems+assessment+of+transcriptional+regulation+on+central+carbon+metabolism+by+Cra+and+CRP.">Systems assessment of transcriptional regulation on central carbon metabolism by Cra and CRP.</a> Nucleic Acids Research. 46 (6), 2901-2917 (2018).</li><li>Niu, 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=In+vivo+genome-wide+binding+interactions+of+mouse+and+human+constitutive+androstane+receptors+reveal+novel+gene+targets.">In vivo genome-wide binding interactions of mouse and human constitutive androstane receptors reveal novel gene targets.</a> Nucleic Acids Research. 46 (16), 8385-8403 (2018).</li><li>Uuskula-Reimand, 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=Topoisomerase+II+beta+interacts+with+cohesin+and+CTCF+at+topological+domain+borders.">Topoisomerase II beta interacts with cohesin and CTCF at topological domain borders.</a> Genome Biology. 17, (2016).</li><li>Rhee, H. 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=Expression+of+Terminal+Effector+Genes+in+Mammalian+Neurons+Is+Maintained+by+a+Dynamic+Relay+of+Transient+Enhancers.">Expression of Terminal Effector Genes in Mammalian Neurons Is Maintained by a Dynamic Relay of Transient Enhancers.</a> Neuron. 92 (6), 1252-1265 (2016).</li><li>Pugh, B. F., Venters, B. 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저자는 공개 할 것이 없습니다.

이 프로토콜에서, 외핵증 소화뒤에 는 초고매핑 해상도에서 포유류 세포에서 단백질-DNA 상호 작용의 식별을 위한 DNA 라이브러리를 얻기 위하여 이용되는 외핵증 소화에 선행된 ChIP. 많은 변수가 ChIP 엑소 실험의 품질에 기여합니다. 중요한 실험 파라미터는 항체의 질, 초음파 처리의 최적화 및 LM-PCR 주기의 수를 포함합니다. 이러한 중요한 실험 파라미터는 ChIP 엑소 실험을 제한할 수 있으며 아래?...

단백질 DNA 상호 작용의 위치는 유전자 조절의 기계장치에 통찰력을 제공합니다. 높은 처리량 시퀀싱(ChIP-seq)과 결합된 크로마틴 면역 침전은 살아있는 세포1,2에서게놈-DNA 상호 작용을 검사하기 위해 10년 동안 사용되어 왔다. 그러나 ChIP-seq 방법은 낮은 매핑 해상도, 거짓 긍정, 부재중 전화 및 비특이적 배경 신호로 이어지는 DNA 단편화 및 불바운드 DNA 오염의 이질성에 의해 제한됩니다. ChIP와 엑소뉴클레아제 소화(ChIP-exo)의 조합은 ChIP-seq 방법을 단백질-DNA 교차 링크 점으로 트리밍하여, 근거리 쌍 분해능 및 낮은 배경 신호3,4,5를제공한다. ChIP 엑소에서 제공하는 매핑 해상도와 낮은 배경은 게놈 전반에 걸쳐 정확하고 포괄적인 단백질 DNA 결합 위치를 결정할 수 있게 합니다. ChIP-exo는 기능적으로 뚜렷한 DNA 결합 모티프, 전사 인자(TF) 및 다중 단백질-DNA 교차 링크 부위를 특정 게놈 결합 위치에서드러낼 수 있으며, 다른 게놈 매핑 방법에 의해 검출할 수 없는3,4,6,7.
ChIP-exo는 처음에 신진 효모에서 TFs의 서열 특이적 DNA 결합을 검사하고, 게놈4,8,9를통해 개별 히스톤의 전사 사전 개시 복합체 및 서브 뉴클레오소말 구조의 정확한 조직을 연구하기 위해 사용되었다. 2011년4년도입 이후, ChIP-exo는 박테리아, 마우스, 인간 세포7,10,11,12,13,14,15,16,17등많은 다른 유기체에서 성공적으로 활용되고있다. 2016년, Rhee 외14는 다른 프로그래밍 TF Isl1을 이용한 이성구복합체를 형성하는 프로그래밍 TF Lhx3의 다운규제 이후 뉴런 유전자 발현이 어떻게 유지되었는지 이해하기 위해 포유류 뉴런에 ChIP-exo를 처음으로 사용했다. 이 연구는 Lhx3의 부재에서, Isl1는 뉴런 이펙터 유전자 유전자의 유전자 발현을 유지하기 위하여 Onecut1 TF에 의해 결합된 새로운 신경 강화에 모집된다는 것을 보여주었습니다. 이 연구에서 ChIP-exo는 여러 TF가 거의 뉴클레오티드 매핑 해상도에서 복합방식으로 세포 유형 및 세포 단계별 DNA 조절 요소를 동적으로 인식하는 방법을 밝혔습니다. 그밖 연구 결과는 또한 그밖 포유류 세포주에서 단백질과 DNA 사이 상호 작용을 이해하기 위하여 ChIP 엑소 방법을 이용했습니다. 한일(7)은 ChIP-exo를 사용하여 ChIP-exo를 사용하여 마우스 에리스로이드 세포에서 GATA1 및 TAL1 TFs의 게놈 전체 조직을 검사하였다. 이 연구는 TAL1이 적혈구 분화를 통해 GATA1과의 단백질 단백질 상호 작용을 간접적으로 통해 간접적으로 DNA에 직접 모집된다는 것을 발견했습니다. 최근 연구는 또한 CTCF, RNA 폴리머라제 II, 및 히스톤 마크의 게놈 전체 결합 위치를 프로파일라기 위해 ChIP-exo를 사용하여 인간 세포주18,19에서최신유전체 및 전사 메커니즘을 연구하였다.
사용할 수있는 ChIP 엑소 프로토콜의 여러 버전이 있습니다3,5,20. 그러나 이러한 ChIP 엑소 프로토콜은 차세대 시퀀싱 라이브러리 준비에 익숙하지 않은 연구를 위해 따르기 어렵다. ChIP 엑소 프로토콜의 우수한 버전은 따라하기 쉬운 지침과 비디오21로게시되었지만 완료하는 데 상당한 시간이 필요한 많은 효소 단계가 포함되어 있습니다. 여기서 는 감소된 효소 단계와 인큐베이션 시간을 포함하는 ChIP 엑소 프로토콜의 새 버전과 각 효소단계(21)에대한 설명을 보고합니다. 최종 수리 및 dA 꼬리 반응은 엔드 준비 효소를 사용하여 단일 단계로 결합됩니다. 인덱스 및 범용 어댑터 리칭 단계의 인큐베이션 시간은 리그레이션 인핸서를 사용하여 2시간에서 15분으로 단축됩니다. 이전 ChIP 엑소 프로토콜에 기재된 인덱스 어댑터 리그션 단계 후의 키나제 반응이 제거된다. 대신, 인산염 군은 오리고 DNA 합성 중에 인덱스 어댑터(표1)의5'끝 중 하나에 첨가되며, 이는 람다 엑소뉴클레아제 소화 단계에 사용될 것이다. 이전 ChIP 엑소 프로토콜은 RecJf exonuclease 소화를 사용하여 단일 좌초 DNA 오염 물질을 제거하는 동안, 이 소화 단계는 ChIP 엑소 라이브러리의 품질에 중요하지 않기 때문에 여기에서 제거됩니다. 또한, ChIP 용출 후 역방향 DNA를 정화하기 위해, 자성 비드 정제 방법은 페놀:클로로폼:이소아밀 알코올(PCIA) 추출 방법 대신에 사용된다. 이것은 DNA 추출의 잠복기 시간을 감소시킵니다. 중요한 것은 인덱스 어댑터 리그레이션 중에 형성된 대부분의 어댑터 디머를 제거하여 계각 매개 PCR의 효율성에 영향을 미칠 수 있습니다.
여기에 제시된 ChIP 엑소 프로토콜은 마우스 배아 줄기(ES) 세포와 분화된 포유류 뉴런에서 정밀한 단백질-DNA 상호작용의 검출에 최적화되어 있다. 간단히, 수확 및 교차 연결된 신경 세포는 크롬틴이 초음파 처리에 노출될 수 있도록, 다음 적절한 크기의 DNA 단편이 얻어지도록 초음파처리(도 1)를용해한다. 항체 코팅 구슬은 그 때 관심있는 단백질에 단편화된, 수용성 크로마틴을 선택적으로 면역침전염하는 데 사용됩니다. 면역 침전 DNA는 여전히 구슬에 있는 동안, 최종 수리, 시퀀싱 어댑터의 결찰, 채우기 반응 및 5' 3' 람다 exonuclease 소화 단계수행된다. 엑소뉴클레아제 소화 단계는 ChIP 엑소에게 초고해상도와 높은 신호 대 잡음 비율을 제공하는 것입니다. 람다 엑소뉴클레아제는 교차 연결 부위로부터 면역 침전 된 DNA를 몇 가지 염기 쌍 (bp)을 트림하여 오염 DNA가 저하됩니다. 엑소뉴클레아제 처리된 ChIP DNA는 항체 코팅 구슬로부터 용출되고, 단백질-DNA 크로스링크는 반전되고, 단백질은 저하된다. DNA는 단일 좌초 된 ChIP DNA에 추출되고 변성되고, 이중 좌초 DNA (dsDNA)를 만들기 위해 프라이머 어닐링 및 확장이 뒤따릅니다. 다음으로, 외핵체 처리 단부에 대한 범용 어댑터의 결찰이 수행된다. 생성된 DNA는 정제되고, PCR이 증폭되고, 겔정제되고, 차세대 시퀀싱을 실시한다.
ChIP 엑소 프로토콜은 ChIP-seq 프로토콜보다 길지만 기술적으로 는 그리 어렵지 않습니다. 모든 성공적으로 면역 침전된 ChIP DNA는 몇 가지 추가 효소 단계로 ChIP 엑소를 실시할 수 있습니다. 초고매핑 해상도, 배경 신호 감소, 게놈 결합 부위에 대한 거짓 긍정 및 네거티브 감소 등 ChIP-exo의 주목할 만한 장점은 시간 비용을 능가합니다.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr >
			<td >Agarose, UltraPure</td>
			<td >Invitrogen</td>
			<td >16500</td>
			<td >Checking Sonication (Section 4.3.6) and Gel Purification of LM-PCR Amplified DNA (Section 19.1)</td>
		</tr>
		<tr >
			<td >Albumin, Bovine Serum (BSA), Protease Free, Heat Shock Isolation, Min. 98%</td>
			<td >BioShop</td>
			<td >ALB003</td>
			<td >Blocking Solution</td>
		</tr>
		<tr >
			<td >Antibody against Isl1</td>
			<td >DSHB</td>
			<td >39.3F7</td>
			<td >Antibody incuation with beads (Section 5.6)</td>
		</tr>
		<tr >
			<td >Bioruptor Pico&#160;</td>
			<td >Diagenode</td>
			<td >B01060010</td>
			<td >Sonicating Chromatin (Section 3.3)</td>
		</tr>
		<tr >
			<td >Bovine serum albumin (BSA), Molecular Biology Grade</td>
			<td >New England BioLabs</td>
			<td >B9000S</td>
			<td >Fill-in Reaction on Beads (Section 10.2) and Denaturing, Primer Annealing and Primer Extension (Section 14.2)</td>
		</tr>
		<tr >
			<td >Centrifuge 5424 R</td>
			<td >Eppendorf</td>
			<td >5404000138</td>
			<td >Sonicating Chromatin (Section 3.5), Checking Sonication (Section 4.3.1, 4.3.3 and 4.3.4)</td>
		</tr>
		<tr >
			<td >Centrifuge 5804 R</td>
			<td >Eppendorf</td>
			<td >22623508</td>
			<td >Harvest, cross-linking and freezing cells (Section 1.3), Cell lysis (Section 2.2 and 2.3), Sonicating Chromatin (Section 3.1)</td>
		</tr>
		<tr >
			<td >cOmplete, Mini, EDTA-free Protease Inhibitor Cocktail</td>
			<td >Roche</td>
			<td >4693159001</td>
			<td >Added to all buffers, except Proteinase K buffer and ChIP Elution buffer</td>
		</tr>
		<tr >
			<td >dATP Solution</td>
			<td >New England BioLabs</td>
			<td >N0440S</td>
			<td >dA-Tailing Reaction (Section 15.1)</td>
		</tr>
		<tr >
			<td >Deoxycholic Acid Sodium Salt</td>
			<td >fisher scientific</td>
			<td >BP349</td>
			<td >Lysis Buffer 3, High Salt Wash Buffer and LiCl Wash Buffer</td>
		</tr>
		<tr >
			<td >dNTP Mix, Molecular Biology Grade</td>
			<td >Thermo Scientific</td>
			<td >R0192</td>
			<td >Fill-in Reaction on Beads (Section 10.2) and Denaturing, Primer Annealing and Primer Extension (Section 14.2)</td>
		</tr>
		<tr >
			<td >DreamTaq Green PCR Master Mix, 2x&#160;</td>
			<td >Thermo Scientific</td>
			<td >K1081</td>
			<td >Ligation-Mediated PCR (Section 18.1)</td>
		</tr>
		<tr >
			<td >EDTA, 0.5 M, Sterile Solution, pH 8.0</td>
			<td >BioShop</td>
			<td >EDT111</td>
			<td >Lysis Buffer 1-3, Checking Sonication (Section 4.1), High Salt Wash Buffer, LiCl Wash Buffer and ChIP Elution Buffer</td>
		</tr>
		<tr >
			<td >Ethyl Alcohol Anhydrous, 100%</td>
			<td >Commercial alcohols</td>
			<td >P006EAAN</td>
			<td >Checking Sonication (Section 4.3.3)</td>
		</tr>
		<tr >
			<td >Formaldehyde, 36.5-38%, contains 10-15% methanol</td>
			<td >Sigma</td>
			<td >F8775</td>
			<td >Harvest, cross-linking and freezing cells (Section 1.1)</td>
		</tr>
		<tr >
			<td >Glycerol, Reagent Grade, min 99.5%</td>
			<td >BioShop</td>
			<td >GLY002</td>
			<td >Lysis Buffer 1</td>
		</tr>
		<tr >
			<td >Glycine, Biotechnology Grade, min. 99%</td>
			<td >BioShop</td>
			<td >GLN001</td>
			<td >Harvest, cross-linking and freezing cells (Section 1.2)</td>
		</tr>
		<tr >
			<td >Glycogen, RNA Grade</td>
			<td >Thermo Scientific</td>
			<td >R0551</td>
			<td >Checking Sonication (Section 4.3.3)</td>
		</tr>
		<tr >
			<td >HEPES, 1 M Sterile-filtered Solution, pH 7.3&#160;</td>
			<td >BioShop</td>
			<td >HEP003</td>
			<td >Lysis Buffer 1, High Salt Wash Buffer</td>
		</tr>
		<tr >
			<td >Klenow Fragment (3-&#62;5 exo-)</td>
			<td >New England BioLabs</td>
			<td >M0212S</td>
			<td >dA-Tailing Reaction (Section 15.1)</td>
		</tr>
		<tr >
			<td >Lambda exonuclease</td>
			<td >New England BioLabs</td>
			<td >M0262S</td>
			<td >Lambda Exonuclease Digestion on Beads (Section 11.2)</td>
		</tr>
		<tr >
			<td >Ligase Enhancer</td>
			<td >New England BioLabs</td>
			<td >E7645S</td>
			<td >NEBNext Ultra II DNA Library Kit. Index Adapter Ligation on Beads (Section 9.1) and Universal Adapter Ligation (Section 16.1)</td>
		</tr>
		<tr >
			<td >Ligase Master Mix</td>
			<td >New England BioLabs</td>
			<td >E7645S</td>
			<td >NEBNext Ultra II DNA Library Kit. Index Adapter Ligation on Beads (Section 9.1) and Universal Adapter Ligation (Section 16.1)</td>
		</tr>
		<tr >
			<td >Lithium Chloride (LiCl), Reagent grade</td>
			<td >Bioshop</td>
			<td >LIT704</td>
			<td >LiCl Wash Buffer</td>
		</tr>
		<tr >
			<td >Magnetic beads for ChIP (Dynabeads Protein G)</td>
			<td >Dynabeads Protein G (magnetic beads for ChIP)</td>
			<td >Dynabeads Protein G (magnetic beads for ChIP)</td>
			<td >Antibody incubation with beads (Section 5)</td>
		</tr>
		<tr >
			<td >Magnetic beads for DNA purification (AMPure XP Beads)</td>
			<td >Beckman Coulter</td>
			<td >A63880</td>
			<td >DNA Extraction (Section 13.3) and DNA Clean-up (Section 17.1)</td>
		</tr>
		<tr >
			<td >Magnetic rack (DynaMag-2 Magnet)</td>
			<td >Invitrogen</td>
			<td >12321D</td>
			<td >Used in many steps in Sections: 5 - 11, 13</td>
		</tr>
		<tr >
			<td >MinElute Gel Extraction Kit</td>
			<td >Qiagen&#160;</td>
			<td >28604</td>
			<td >Gel Purification of PCR Amplified DNA (Section 19.2)</td>
		</tr>
		<tr >
			<td >N-Lauroylsarcosine sodium salt solution, 30% aqueous solution, &#8805;97.0% (HPLC)</td>
			<td >Sigma</td>
			<td >61747</td>
			<td >Lysis Buffer 3</td>
		</tr>
		<tr >
			<td >Octylphenol Ethoxylate (IGEPAL CA630)</td>
			<td >BioShop</td>
			<td >NON999</td>
			<td >Lysis Buffer 1 and LiCl Wash Buffer</td>
		</tr>
		<tr >
			<td >Phenol:Chloroform:Isoamyl Alcohol, Biotechnology Grade (25:24:1)</td>
			<td >BioShop</td>
			<td >PHE512</td>
			<td >Checking Sonication (Section 4.3.1)</td>
		</tr>
		<tr >
			<td >phi29 DNA Polymerase</td>
			<td >New England BioLabs</td>
			<td >M0269L</td>
			<td >Fill-in Reaction on Beads (Section 10.2) and Denaturing, Primer Annealing and Primer Extension (Section 14.3 and 14.4)</td>
		</tr>
		<tr >
			<td >Phosphate-Buffered Saline (PBS), 1x&#160;</td>
			<td >Corning</td>
			<td >21040CV</td>
			<td >Harvest, cross-linking and freezing cells (Section 1.3) and Sonicating Chromatin (Section 3.1), Antibody incuation with beads (Section 5.1)</td>
		</tr>
		<tr >
			<td >PowerPac Basic Power Supply</td>
			<td >BioRad</td>
			<td >1645050</td>
			<td >Checking Sonication (Section 4.3.6) and Gel Purification of LM-PCR Amplified DNA (Section 19.1)</td>
		</tr>
		<tr >
			<td >ProFlex PCR System</td>
			<td >Applied Biosystems</td>
			<td >ProFlex PCR System</td>
			<td >Used in Sections: 14.2, 14.4, 15.2, 16.2 and 18.2</td>
		</tr>
		<tr >
			<td >Protein LoBind Tube, 2.0 mL&#160;</td>
			<td >Eppendorf</td>
			<td >22431102</td>
			<td >Antibody Incubation with Beads (Section 5.2) and Chromatin Immunoprecipitation (Section 6.3)</td>
		</tr>
		<tr >
			<td >Proteinase K Solution, RNA Grade</td>
			<td >Invitrogen</td>
			<td >25530049</td>
			<td >Checking Sonication (Section 4.2) and Elution and Reverse Crosslinking (Section 12.3)</td>
		</tr>
		<tr >
			<td >Qubit 4.0 Fluorometer</td>
			<td >Invitrogen</td>
			<td >Q33226</td>
			<td >Gel Purification of PCR Amplified DNA (Section 19.3)</td>
		</tr>
		<tr >
			<td >Quibit dsDNA BR assay kit</td>
			<td >Invitrogen</td>
			<td >Q32853</td>
			<td >Gel Purification of PCR Amplified DNA (Section 19.3)</td>
		</tr>
		<tr >
			<td >Rnase A, Dnase and Protease-free</td>
			<td >Thermo Scientific</td>
			<td >EN0531</td>
			<td >Checking Sonication (Section 4.3.2) and DNA Extraction (Section 13.2)</td>
		</tr>
		<tr >
			<td >Sodium chloride (NaCl), BioReagent&#160;</td>
			<td >Sigma</td>
			<td >S5886</td>
			<td >Lysis Buffer 1-3, High Salt Wash Buffer</td>
		</tr>
		<tr >
			<td >Sodium Dodecyl Sulfate (SDS), Electrophoresis Grade</td>
			<td >BioShop</td>
			<td >SDS001</td>
			<td >Checking Sonication (Section 4.1), High Salt Wash Buffer and ChIP Elution Buffer</td>
		</tr>
		<tr >
			<td >Sonication beads and 15 mL Bioruptor Tubes</td>
			<td >Diagenode</td>
			<td >C01020031</td>
			<td >Sonicating Chromatin (Section 3.1 and 3.2)</td>
		</tr>
		<tr >
			<td >ThermoMixer F1.5&#160;</td>
			<td >Eppendorf</td>
			<td >5384000020</td>
			<td >Section 4.2, 4.3.2, 4.3.5, 8.2, 9.2, 10.3, 11.2, 12.2, 12.3, 13.2 and 16.2</td>
		</tr>
		<tr >
			<td >Trizma hydrochloride solution (Tris-HCl), BioPerformance Certified, 1 M, pH 7.4</td>
			<td >Sigma</td>
			<td >T2194</td>
			<td >10 mM Tris-HCl Buffer</td>
		</tr>
		<tr >
			<td >Trizma hydrochloride solution (Tris-HCl), BioPerformance Certified, 1 M, pH 8.0</td>
			<td >Sigma</td>
			<td >T2694</td>
			<td >Lysis Buffer 2, Lysis Buffer 3, Checking Sonication (Section 4.1), LiCl Wash Buffer and ChIP Elution Buffer</td>
		</tr>
		<tr >
			<td >Ultra II End Repair/dA-Tailing Module (24 rxn -&#62; 120 rxn)</td>
			<td >New England BioLabs</td>
			<td >E7546S</td>
			<td >End Prep Reaction mix and End Prep Enzyme mix. End-repair and dA-Tailing Reaction on Beads (Section 8.2)</td>
		</tr>
		<tr >
			<td >VWR Mini Tube Rocker, Variable Speed</td>
			<td >VWR</td>
			<td >10159-752</td>
			<td >Used in many steps in sections: 1, 2, 5, 6 and 7</td>
		</tr>
		<tr >
			<td >2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol, Triton X-100, Reagent Grade</td>
			<td >BioShop</td>
			<td >TRX506</td>
			<td >Lysis Buffer 1, Sonicating Chromatin (Section 3.4) and High Salt Wash Buffer</td>
		</tr>
	</tbody>
</table>

high-resolution mapping of protein-dna interactions in mouse stem cell-derived neurons using chromatin immunoprecipitation-exonuclease (chip-exo)

게놈에 특정 단백질-DNA 상호 작용의 식별은 유전자 조절을 이해하는 데 중요합니다. 높은 처리량 시퀀싱 (ChIP-seq)과 결합된 크로마틴 면역 침전은 DNA 결합 단백질의 게놈 전체 결합 위치를 식별하는 데 널리 사용됩니다. 그러나 ChIP-seq 방법은 초음파 처리된 DNA 단편 및 비특이적 배경 DNA의 길이에 있는 이질성에 의해 제한되어 DNA 결합 부위의 낮은 매핑 해상도 및 불확실성을 초래합니다. 이러한 한계를 극복하기 위해 ChIP와 엑소뉴클레아제 소화(ChIP-exo)의 조합은 5'에서 3' 엑소뉴클레아제 소화를 활용하여 단백질-DNA 교차 링크 부위에 이질적으로 크기의 면역 침전DNA를 다듬는다. 엑소뉴클레아제 치료는 또한 비특이적 배경 DNA를 제거한다. 라이브러리가 준비된 외핵증 소화 DNA는 고처리량 시퀀싱을 위해 전송될 수 있다. ChIP 엑소 방법을 사용하면 감지 감도가 높아지고 배경 신호가 감소하는 근거리 쌍 매핑 해상도가 가능합니다. 포유류 세포 및 차세대 시퀀싱을 위한 최적화된 ChIP 엑소 프로토콜은 아래에 설명되어 있다.

도 2A는 마우스 ES 세포로부터 분화된 모터 뉴런 세포의 다양한 사이클을 통해 세포 리시스 및 초음파 처리 후 초음파 처리 결과를 도시한다. 초음파 처리 주기의 최적 수 (예를 들어, 도 2A에서12 사이클) 100-400 bp DNA 단편에서 강한 DNA 강도를 생성. 고품질 ChIP 엑소 라이브러리는 단편화된 크로마틴 DNA의 크기와 양을 기반으로 합니다. 따라서, ChIP 엑소를 ?...

Watch this Scientific Journal Video about High-Resolution Mapping of Protein-DNA Interactions in Mouse Stem Cell-Derived Neurons using Chromatin Immunoprecipitation-Exonuclease ChIP-Exo at JoVE.com

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

게놈 전반에 걸친 단백질 결합 위치의 정확한 결정은 유전자 조절을 이해하는 데 중요합니다. 여기서는 외핵증 소화(ChIP-exo)를 사용한 크로마틴-면역침전DNA를 치료하는 게놈 매핑 방법을 설명하고 있으며, 이어서 고처리량 시퀀싱을 한다. 이 방법은 포유류 뉴런에서 근거리 쌍 매핑 해상도 및 높은 신호 대 잡음 비와 단백질 DNA 상호 작용을 검출합니다.

크롬 마틴 면역 침전 -엑소뉴클레아제 (ChIP-Exo)를 사용하여 마우스 줄기 세포 유래 뉴런에서 단백질 DNA 상호 작용의 고해상도 매핑

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

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JoVE Journal

Genetics

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

4.7K 조회수.  University of Toronto. 게놈 전반에 걸친 단백질 결합 위치의 정확한 결정은 유전자 조절을 이해하는 데 중요합니다. 여기서는 외핵증 소화(ChIP-exo)를 사용한 크로마틴-면역침전DNA를 치료하는 게놈 매핑 방법을 설명하고 있으며, 이어서 고처리량 시퀀싱을 한다. 이 방법은 포유류 뉴런에서 근거리 쌍 매핑 해상도 및 높은 신호 대 잡음 비와 단백질 DNA 상호 작용을 검출합니다.

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

Mapping RNA-RNA Interactions Globally Using Biotinylated Psoralen

Knowing how RNAs interact with themselves and with others is key to understanding RNA based gene regulation in the cell. While examples of RNA-RNA interactions such as microRNA-mRNA interactions have been shown to regulate gene expression, the full extent to which RNA interactions occur in the cell is still unknown. Previous methods to study RNA interactions have primarily focused on subsets of RNAs that are interacting with a particular protein or RNA species. Here, we detail a method named Sequencing of Psoralen crosslinked, Ligated, and Selected Hybrids (SPLASH) that allows genome-wide capture of RNA interactions in vivo in an unbiased manner. SPLASH utilizes in vivo crosslinking, proximity ligation, and high throughput sequencing to identify intramolecular and intermolecular RNA base-pairing partners globally. SPLASH can be applied to different organisms including bacteria, yeast and human cells, as well as diverse cellular conditions to facilitate the understanding of the dynamics of RNA organization under diverse cellular contexts. The entire experimental SPLASH protocol takes about 5 days to complete and the computational workflow takes about 7 days to complete.

Here, we detail the method of Sequencing of Psoralen crosslinked, Ligated, and Selected Hybrids (SPLASH), which enables genome-wide mapping of intramolecular and intermolecular RNA-RNA interactions in vivo. SPLASH can be applied to study RNA interactomes of organisms including yeast, bacteria and humans.

Biotinylated Psoralen을 사용하여 RNA-RNA 상호 작용을 세계적으로 매핑

Knowing how RNAs interact with themselves and with others is key to understanding RNA based gene regulation in the cell. While examples of RNA-RNA ...

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유전학

Genome-wide Mapping of Protein-DNA Interactions with ChEC-seq in Saccharomyces cerevisiae

Genome-wide mapping of protein-DNA interactions is critical for understanding gene regulation, chromatin remodeling, and other chromatin-resident processes. Formaldehyde crosslinking followed by chromatin immunoprecipitation and high-throughput sequencing (X-ChIP-seq) has been used to gain many valuable insights into genome biology. However, X-ChIP-seq has notable limitations linked to crosslinking and sonication. Native ChIP avoids these drawbacks by omitting crosslinking, but often results in poor recovery of chromatin-bound proteins. In addition, all ChIP-based methods are subject to antibody quality considerations. Enzymatic methods for mapping protein-DNA interactions, which involve fusion of a protein of interest to a DNA-modifying enzyme, have also been used to map protein-DNA interactions. We recently combined one such method, chromatin endogenous cleavage (ChEC), with high-throughput sequencing as ChEC-seq. ChEC-seq relies on fusion of a chromatin-associated protein of interest to micrococcal nuclease (MNase) to generate targeted DNA cleavage in the presence of calcium in living cells. ChEC-seq is not based on immunoprecipitation and so circumvents potential concerns with crosslinking, sonication, chromatin solubilization, and antibody quality while providing high resolution mapping with minimal background signal. We envision that ChEC-seq will be a powerful counterpart to ChIP, providing an independent means by which to both validate ChIP-seq findings and discover new insights into genomic regulation.

Genome-wide Mapping of Protein-DNA Interactions with ChEC-seq in Saccharomyces cerevisiae

We describe chromatin endogenous cleavage coupled with high-throughput sequencing (ChEC-seq), a chromatin immunoprecipitation (ChIP)-orthogonal method for mapping protein binding sites genome-wide with micrococcal nuclease (MNase) fusion proteins.

ChEC-seq와의 단백질 - DNA 상호 작용의 게놈 전체 매핑<em&gt; 사카로 마이 세스 세레 비시 애</em

Genome-wide mapping of protein-DNA interactions is critical for understanding gene regulation, chromatin remodeling, and other chromatin-resident ...

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.

마우스 T- 세포주에서 Chromatin Immunoprecipitation (ChIP)

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

Retroviral Scanning: Mapping MLV Integration Sites to Define Cell-specific Regulatory Regions

Moloney murine leukemia (MLV) virus-based retroviral vectors integrate predominantly in acetylated enhancers and promoters. For this reason, mLV integration sites can be used as functional markers of active regulatory elements. Here, we present a retroviral scanning tool, which allows the genome-wide identification of cell-specific enhancers and promoters. Briefly, the target cell population is transduced with an mLV-derived vector and genomic DNA is digested with a frequently cutting restriction enzyme. After ligation of genomic fragments with a compatible DNA linker, linker-mediated polymerase chain reaction (LM-PCR) allows the amplification of the virus-host genome junctions. Massive sequencing of the amplicons is used to define the mLV integration profile genome-wide. Finally, clusters of recurrent integrations are defined to identify cell-specific regulatory regions, responsible for the activation of cell-type specific transcriptional programs.
The retroviral scanning tool allows the genome-wide identification of cell-specific promoters and enhancers in prospectively isolated target cell populations. Notably, retroviral scanning represents an instrumental technique for the retrospective identification of rare populations (e.g. somatic stem cells) that lack robust markers for prospective isolation.

Here, we describe a protocol for genome-wide mapping of the integration sites of Moloney murine leukemia virus-based retroviral vectors in human cells.

레트로 바이러스 스캐닝 : MLV 통합 사이트 맵핑으로 세포 특정 규제 지역 정의

Moloney murine leukemia (MLV) virus-based retroviral vectors integrate predominantly in acetylated enhancers and promoters. For this reason, mLV ...

High Resolution Fluorescent In Situ Hybridization in Drosophila Embryos and Tissues Using Tyramide Signal Amplification

In our efforts to determine the patterns of expression and subcellular localization of Drosophila RNAs on a genome-wide basis, and in a variety of tissues, we have developed numerous modifications and improvements to our original fluorescent in situ hybridization (FISH) protocol. To facilitate throughput and cost effectiveness, all steps, from probe generation to signal detection, are performed using exon 96-well microtiter plates. Digoxygenin (DIG)-labelled antisense RNA probes are produced using either cDNA clones or genomic DNA as templates. After tissue fixation and permeabilization, probes are hybridized to transcripts of interest and then detected using a succession of anti-DIG antibody conjugated to biotin, streptavidin conjugated to horseradish peroxidase (HRP) and fluorescently conjugated tyramide, which in the presence of HRP, produces a highly reactive intermediate that binds to electron dense regions of immediately adjacent proteins. These amplification and localization steps produce a robust and highly localized signal that facilitates both cellular and subcellular transcript localization. The protocols provided have been optimized to produce highly specific signals in a variety of tissues and developmental stages. References are also provided for additional variations that allow the simultaneous detection of multiple transcripts, or transcripts and proteins, at the same time.

High Resolution Fluorescent In Situ Hybridization in Drosophila Embryos and Tissues Using Tyramide Signal Amplification

The described RNA in situ hybridization protocol allows the detection of RNA in whole Drosophila embryos or dissected tissues. Using 96-well microtiter plates and tyramide signal amplification, transcripts can be detected at high resolution, sensitivity, and throughput, and at a relatively low cost.

높은 해상도 교 잡 형광 제자리에 초파리 태아와 Tyramide 신호 증폭을 사용 하 여 조직에서

In our efforts to determine the patterns of expression and subcellular localization of Drosophila RNAs on a genome-wide basis, and in a variety of ...

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.

ATAC Seq에 의해 기본 인간 T 림프 톨에 게놈 넓은 접근 Chromatin 매핑

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

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.

발기인 캡처 안녕-c: 고해상도, 게놈 넓은 발기인 상호 작용의 프로 파일링

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

CRISPR-Mediated Reorganization of Chromatin Loop Structure

Recent studies have clearly shown that long-range, three-dimensional chromatin looping interactions play a significant role in the regulation of gene expression, but whether looping is responsible for or a result of alterations in gene expression is still unknown. Until recently, how chromatin looping affects the regulation of gene activity and cellular function has been relatively ambiguous, and limitations in existing methods to manipulate these structures prevented in-depth exploration of these interactions. To resolve this uncertainty, we engineered a method for selective and reversible chromatin loop re-organization using CRISPR-dCas9 (CLOuD9). The dynamism of the CLOuD9 system has been demonstrated by successful localization of CLOuD9 constructs to target genomic loci to modulate local chromatin conformation. Importantly, the ability to reverse the induced contact and restore the endogenous chromatin conformation has also been confirmed. Modulation of gene expression with this method establishes the capacity to regulate cellular gene expression and underscores the great potential for applications of this technology in creating stable de novo chromatin loops that markedly affect gene expression in the contexts of cancer and development.

Chromatin looping plays a significant role in gene regulation; however, there have been no technological advances that allow for selective and reversible modification of chromatin loops. Here we describe a powerful system for chromatin loop re-organization using CRISPR-dCas9 (CLOuD9), demonstrated to selectively and reversibly modulate gene expression at targeted loci.

Recent studies have clearly shown that long-range, three-dimensional chromatin looping interactions play a significant role in the regulation of gene ...

High-Resolution Comparison of Bacterial Conjugation Frequencies

Bacterial conjugation is an important step in the horizontal transfer of antibiotic resistance genes via a conjugative DNA element. In-depth comparisons of conjugation frequency under different conditions are required to understand how the conjugative element spreads in nature. However, conventional methods for comparing conjugation frequency are not appropriate for in-depth comparisons because of the high background caused by the occurrence of additional conjugation events on the selective plate. We successfully reduced the background by introducing a most probable number (MPN) method and a higher concentration of antibiotics to prevent further conjugation in selective liquid medium. In addition, we developed a protocol for estimating the probability of how often donor cells initiate conjugation by sorting single donor cells into recipient pools by fluorescence-activated cell sorting (FACS). Using two plasmids, pBP136 and pCAR1, the differences in conjugation frequency in Pseudomonas putida cells could be detected in liquid medium at different stirring rates. The frequencies of conjugation initiation were higher for pBP136 than for pCAR1. Using these results, we can better understand the conjugation features in these two plasmids.

With an aim to understand the behaviors of various bacterial conjugative DNA elements under different conditions, we describe a protocol for detecting differences in conjugation frequency, with high resolution, to estimate how efficiently the donor bacterium initiates conjugation.

세균성 활용 주파수의 고해상도 비교

Bacterial conjugation is an important step in the horizontal transfer of antibiotic resistance genes via a conjugative DNA element. In-depth comparisons ...

Chromatin Immunoprecipitation Assay Using Micrococcal Nucleases in Mammalian Cells

To express cellular phenotypes in organisms, living cells execute gene expression accordingly, and transcriptional programs play a central role in gene expression. The cellular transcriptional machinery and its chromatin modification proteins coordinate to regulate transcription. To analyze transcriptional regulation at the molecular level, several experimental methods such as electrophoretic mobility shift, transient reporter and chromatin immunoprecipitation (ChIP) assays are available. We describe a modified ChIP assay in detail in this article because of its advantages in directly showing histone modifications and the interactions between proteins and DNA in cells. One of the key steps in a successful ChIP assay is chromatin shearing. Although sonication is commonly used for shearing chromatin, it is difficult to identify reproducible conditions. Instead of shearing chromatin by sonication, we utilized enzymatic digestion with micrococcal nuclease (MNase) to obtain more reproducible results. In this article, we provide a straightforward ChIP assay protocol using MNase.

Chromatin immunoprecipitation (ChIP) is a powerful tool for understanding the molecular mechanisms of gene regulation. However, the method involves difficulties in obtaining reproducible chromatin fragmentation by mechanical shearing. Here, we provide an improved protocol for a ChIP assay using enzymatic digestion.

포유류 세포에서 미세 Coccal 뉴클레아제사용 염색질 면역침전 분석

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