We thank the Venters Lab and members of the Molecular Physiology and Biophysics Department for helpful discussions. Special thanks to Frank Pugh for his guidance, mentoring, and many insightful discussions on the nuances of ChIP-exo while I was a post-doctoral fellow in his laboratory.

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The authors have nothing to disclose.

<html> 우리는 염색질 근처 염기쌍 해상도 편견, 게놈 차원의 방식으로 단백질 상호 작용에 대한 정확한 결합 위치를 결정하기 위해 기능 유전체학 프로토콜을 제시한다. 면역 침전이 자성 수지에 남아있는 동안 근처 염기쌍 매핑 해상도를 얻기 위해 가장 중요한 단계는 칩 - 풍부 DNA의 엑소 뉴 클레아 제 처리이다. 표면 상, 단백질 복합체는 잠재적으로 주어진 서브 유닛 (예를 들어, 크로 마?...

크로 마틴 면역 침강 (칩)을 선택적으로 살아있는 세포에서 특정 단백질과 상호 작용하는 DNA 단편을 위해 농축에 의해 유전자 조절 메커니즘을 연구하는 강력한 방법이다. 기술은 높은 처리량 시퀀싱 (칩-SEQ) 1 올리고 뉴클레오티드 마이크로 어레이 (칩 - 칩)에 하이브리드에 하나의 궤적 (표준 칩-qPCR에) 검출에서 향상으로 칩 농축 DNA 단편의 검출 방법은 진화했다. 칩-서열이 광범위한 응용 프로그램, 염색질 이질성과 비특이적 DNA 상호 작용을 볼 수 있지만 오탐 (false positive)과 부정확 한 매핑 최고의 데이터 품질을 방해했다. 이러한 제한을 우회하기 위해, 박사 프랭크 퓨는 칩 - 엑소 방법 (2)를 개발했다. 칩 엑소의 두드러진 특징은 효율적으로 위치를 결합 전사 인자를 footprinting에, 엑소 뉴 클레아 &#39;3&#39;, 5를 포함하고 있다는 것이다. 결과적으로, 칩 - 엑소 방법은 높은 해상도 detectio의 큰 동적 범위를 달성n 및 낮은 소음. 칩 - 엑소 좀 더 기술적으로 어려운 칩-서열보다 마스터하지만 연구는 다양한 생물학적 시스템 3-8를 사용하여 고유의 초 고해상도 통찰력을 확보하는 것을 목표로, 그것은 널리 채택되고있다. 실제로, 칩 엑소 성공적 박테리아, 효모, 마우스, 래트, 인간 세포 시스템에 적용되어왔다. 원리의 증거로, 칩 - 엑소는 원래 효모 전사의 소수는 2 요인에 대한 정확한 바인딩 모티브를 식별하는 데 사용되었다. 이 기술은 또한 전사 개시전 복합체의 구성을 연구하기 위해 다양한 히스톤 9,10 subnucleosomal의 구조를 해독 효모에 사용 하였다. 최근에, 우리는 인간의 발기인에 이벤트를 바인딩 인접 TFIIB와 폴 II를 해결하기 위해 칩 - 엑소을 활용, 별개의 개시 11 복합체에서 널리 발산 전사가 발생하는 것으로 나타났다. 여기에 제시된 워크 플로우 최적화의있다포유 동물 칩 - 엑소 (그림 1)에 대한 treamlined. 첫째, 생활 차 또는 조직 배양 세포를 공유 가교를 통해 생체 내 단백질 DNA 상호 작용에 보존하는 포름 알데히드로 처리됩니다. 세포 용균 및 염색질은 100 ~ 전단된다 - 500 염기쌍 크기 단편. 칩은 선택적으로 관심있는 단백질에 가교 결합 된 DNA 단편에 대한 풍부. 이 시점에서, 칩은 일반적 서열 라이브러리 본질적 수백 염기쌍 단편의 평균 크기를 검출 해상도를 제한하는 제조된다. 그러나, 칩 엑소 왼쪽 및 람다 엑소 뉴 클레아 제와 단백질의 DNA 가교 부위의 바로 5 &#39;DNA 경계를 트리밍함으로써 이러한 제한을 극복한다. 아래에 설명 된대로 시퀀싱 라이브러리는 다음 엑소 뉴 클레아 제 소화 DNA로 구성되어있다. 얻어진 중첩 5 &#39;테두리 단백질 DNA 상호 작용 (도 1, 스텝 14)의 생체 내 공간을 나타내고, 높은 처리량 시퀀싱에 의해 검출된다. Alt 키무릎이 칩 엑소 방법은 칩-서열보다 더 복잡 대부분의 단계 사이의 전환은 샘플 손실과 실험적인 변동성을 최소화 간단한 비드 세척을 필요로한다. 중요한 것은, 칩 - 엑소는 칩-SEQ, 또한 칩 - 엑소에 성공한다 칩-서열에 성공하는 샘플의 세련된 버전 때문이다. 칩 서열에서 근본적으로 구별되는 데이터 구조의 칩 엑소 결과 단백질 DNA의 상호 작용의 생체 배출량 측정. 공통 칩 서열 발신자가 가장 정확한 피크 호출을 수득 칩 엑소 데이터에 적용될 수 있지만, 우리는 특별히 염두 칩 엑소 데이터의 독특한 구조로 설계 정보학 도구를 추천한다. 이들은 Genetrack, GEM, MACE, Peakzilla 및 ExoProfiler 12-15을 포함한다.

<table><tbody><tr><td>37% formaldehyde, methanol free, 10 x 10 ml ampules</td><td>ThermoFisher Scientific</td><td>28908</td><td>Section 3</td></tr><tr><td>Complete Protease Inhibitor cocktail (CPI)</td><td>Roche Life Science</td><td>11873580001</td><td>Sections 4, 8</td></tr><tr><td>Bioruptor sonicator</td><td>Diagenode</td><td>UCD200</td><td>Section 5</td></tr><tr><td>15 ml polystyrene tubes</td><td>BD Falcon</td><td>352095</td><td>Section 5</td></tr><tr><td>MagSepharose Protein G Xtra beads</td><td>GE Healthcare</td><td>28-9670-66</td><td>Section 6</td></tr><tr><td>DynaMag-1.5 ml Side Magnetic Rack</td><td>Invitrogen</td><td>12321D</td><td>Sections 6-17, 22</td></tr><tr><td>Mini-Tube Rotator</td><td>Fisher Scientific</td><td>05-450-127</td><td>Sections 7, 22</td></tr><tr><td>T4 DNA Polymerase</td><td>New England BioLabs</td><td>M0203</td><td>Section 9</td></tr><tr><td>DNA Polymerase I, Klenow</td><td>New England BioLabs</td><td>M0210</td><td>Section 9</td></tr><tr><td>10x NEBuffer 2 (10x Reaction Buffer 2)</td><td>New England BioLabs</td><td>B7002</td><td>Sections 9-11, 13, 15, 20</td></tr><tr><td>Thermomixer C</td><td>Eppendorf</td><td>5382</td><td>Sections 9-16</td></tr><tr><td>ATP</td><td>Roche Life Science</td><td>010419979001</td><td>Sections 9, 11, 13</td></tr><tr><td>dNTPs</td><td>New England BioLabs</td><td>N0447</td><td>Sections 9, 12, 19, 23</td></tr><tr><td>T4 Polynucleotide Kinase</td><td>New England BioLabs</td><td>M0201</td><td>Sections 9, 13</td></tr><tr><td>dATP</td><td>New England BioLabs</td><td>N0440</td><td>Sections 10, 20</td></tr><tr><td>Klenow 3&#039;-5&#039; Exo Minus</td><td>New England BioLabs</td><td>M0212</td><td>Sections 10, 20</td></tr><tr><td>T4 DNA ligase&amp;nbsp;</td><td>New England BioLabs</td><td>M0202</td><td>Sections 11, 21</td></tr><tr><td>&amp;Phi;-29 DNA Polymerase</td><td>New England BioLabs</td><td>M0269</td><td>Sections 12, 19</td></tr><tr><td>10x &amp;Phi;-29 Buffer</td><td>New England BioLabs</td><td>B0269</td><td>Sections 12, 19</td></tr><tr><td>Lambda Exonuclease</td><td>New England BioLabs</td><td>M0262</td><td>Section 14</td></tr><tr><td>10x Lambda Buffer</td><td>New England BioLabs</td><td>B0262</td><td>Section 14</td></tr><tr><td>RecJ&lt;sub&gt;f&lt;/sub&gt; Exonuclease</td><td>New England BioLabs</td><td>M0264</td><td>Section 15</td></tr><tr><td>Proteinase K</td><td>Roche Life Science</td><td>03115828001</td><td>Section 16</td></tr><tr><td>Glycogen</td><td>Roche Life Science</td><td>010901393001</td><td>Section 18</td></tr><tr><td>10x T4 Ligase Buffer</td><td>New England BioLabs</td><td>B0202</td><td>Section 21</td></tr><tr><td>AMPure XP (clean up) beads&amp;nbsp;</td><td>Beckman Coulter</td><td>A63881</td><td>Section 22</td></tr><tr><td>Q5 Hot Start DNA Polymerase&amp;nbsp;</td><td>New England BioLabs</td><td>M0493</td><td>Section 23</td></tr><tr><td>5x Q5 Buffer (5x PCR Buffer)</td><td>New England BioLabs</td><td>B9027</td><td>Section 23</td></tr><tr><td>QIAquick Gel Extraction Kit</td><td>Qiagen</td><td>28704</td><td>Section 25</td></tr><tr><td>Qubit Fluorometer</td><td>Invitrogen</td><td>Q33216</td><td>Section 26</td></tr><tr><td>Optical Clear Qubit tubes&amp;nbsp;</td><td>Invitrogen</td><td>Q32856</td><td>Section 26</td></tr><tr><td>Qubit dsDNA High Sensitivity Assay kit</td><td>Invitrogen</td><td>Q32851</td><td>Section 26</td></tr></tbody></table>

the chip-exo method: identifying protein-dna interactions with near base pair precision

크로 마틴 면역 침강 (칩)은 후성 유전학 및 특정 단백질 DNA 상호 작용을 분리 유전자 조절의 분야에서 필수적인 도구입니다. 높은 처리량 시퀀싱 (칩 서열)에 결합 된 칩은 일반적으로 염색질 상호 작용 단백질의 게놈 위치를 결정하기 위해 사용된다. 그러나, 칩 서열은 수백 염기쌍 비교적 낮은 매핑 해상도 및 높은 백그라운드 신호에 의해 방해된다. 칩 엑소 방법은 실질적으로 해상도 및 노이즈 모두 개선 한 칩 서열의 정제 된 버전이다. 칩 엑소 방법론의 키 차이는 효과적으로 왼쪽 풋 프린트 라이브러리 준비 워크 플로의 람다 엑소 뉴 클레아 제 소화의 설립 및 단백질 DNA의 가교 사이트의 오른쪽 5 &#39;DNA 테두리입니다. 칩 엑소 라이브러리는 다음 높은 처리량 시퀀싱을 실시한다. 얻어진 데이터는 기능적 조직 O에 고유 초 고해상도 통찰력을 제공하기 위해 활용 될 수있다게놈 바. 여기, 우리는 우리가 최적화 및 포유류 시스템과 차세대 시퀀싱 합성에 의한 플랫폼 간소화 한 칩 - 엑소 방법을 설명합니다.

다음 그림은 여기에 제시된 칩 - 엑소 프로토콜 대표 결과를 보여줍니다. 몇 효소 단계를 기존의 칩-SEQ 방법과는 달리, 칩 - 엑소는 열한 순차적으로 의존 효소 반응 (그림 1)가 필요합니다. 따라서, 치료는 각 반응 성분이 각각의 반응 마스터 믹스에 추가되도록 각 단계에서 수행되어야한다. 우리는 생성 된 표를 인쇄하는 자동 반응 마스터 믹스 계산을 수행하?...

Watch this Scientific Journal Video about The ChIP-exo Method: Identifying Protein-DNA Interactions with Near Base Pair Precision at JoVE.com

The ChIP-exo Method: Identifying Protein-DNA Interactions with Near Base Pair Precision

Here, we present a protocol to achieve near base pair resolution of protein-DNA interactions. This is obtained by exonuclease treatment of DNA fragments selectively enriched by chromatin immunoprecipitation (ChIP-exo) followed by high throughput sequencing.

칩 엑소 방법 : 가까운 자료 쌍의 정밀과 단백질 DNA 상호 작용을 확인

Chromatin immunoprecipitation (ChIP) is an indispensable tool in the fields of epigenetics and gene regulation that isolates specific protein-DNA ...

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16.5K 조회수.  Vanderbilt University. Here, we present a protocol to achieve near base pair resolution of protein-DNA interactions. This is obtained by exonuclease treatment of DNA fragments selectively enriched by chromatin immunoprecipitation (ChIP-exo) followed by high throughput sequencing.

비디오: The ChIP-exo Method: Identifying Protein-DNA Interactions with Near Base Pair Precision

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 ...

연구

유전학

Adaptation of Hybridization Capture of Chromatin-associated Proteins for Proteomics to Mammalian Cells

The hybridization capture of chromatin-associated proteins for proteomics (HyCCAPP) technology was initially developed to uncover novel DNA-protein interactions in yeast. It allows analysis of a target region of interest without the need for prior knowledge about likely proteins bound to the target region. This, in theory, allows HyCCAPP to be used to analyze any genomic region of interest, and it provides sufficient flexibility to work in different cell systems. This method is not meant to study binding sites of known transcription factors, a task better suited for Chromatin Immunoprecipitation (ChIP) and ChIP-like methods. The strength of HyCCAPP lies in its ability to explore DNA regions for which there is limited or no knowledge about the proteins bound to it. It can also be a convenient method to avoid biases (present in ChIP-like methods) introduced by protein-based chromatin enrichment using antibodies. Potentially, HyCCAPP can be a powerful tool to uncover truly novel DNA-protein interactions. To date, the technology has been predominantly applied to yeast cells or to high copy repeat sequences in mammalian cells. In order to become the powerful tool we envision, HyCCAPP approaches need to be optimized to efficiently capture single-copy loci in mammalian cells. Here, we present our adaptation of the initial yeast HyCCAPP capture protocol to human cell lines, and show that single-copy chromatin regions can be efficiently isolated with this modified protocol.

This is a method to identify novel DNA-interacting proteins at specific target loci, relying on sequence-specific capture of crosslinked chromatin for subsequent proteomic analyses. No prior knowledge about potential binding proteins, nor cell modifications are required. Initially developed for yeast, the technology has now been adapted for mammalian cells.

교 잡의 적응 포유류 세포 단백질 Chromatin 관련 단백질의 캡처

The hybridization capture of chromatin-associated proteins for proteomics (HyCCAPP) technology was initially developed to uncover novel DNA-protein ...

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

Identification of specific protein-DNA interactions on the genome is important for understanding gene regulation. Chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-seq) is widely used to identify genome-wide binding locations of DNA-binding proteins. However, the ChIP-seq method is limited by its heterogeneity in length of sonicated DNA fragments and non-specific background DNA, resulting in low mapping resolution and uncertainty in DNA-binding sites. To overcome these limitations, the combination of ChIP with exonuclease digestion (ChIP-exo) utilizes 5&#8217; to 3&#8217; exonuclease digestion to trim the heterogeneously sized immunoprecipitated DNA to the protein-DNA crosslinking site. Exonuclease treatment also eliminates non-specific background DNA. The library-prepared and exonuclease-digested DNA can be sent for high-throughput sequencing. The ChIP-exo method allows for near base-pair mapping resolution with greater detection sensitivity and reduced background signal. An optimized ChIP-exo protocol for mammalian cells and next-generation sequencing is described below.

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

Precise determination of protein-binding locations across the genome is important for understanding gene regulation. Here we describe a&#160;genomic mapping method that treats chromatin-immunoprecipitated DNA with exonuclease digestion (ChIP-exo) followed by high-throughput sequencing. This method detects protein-DNA interactions with near base-pair mapping resolution and high signal-to-noise ratio in mammalian neurons.

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 ...

CD Spectroscopy to Study DNA-Protein Interactions

Circular dichroism (CD) spectroscopy is a simple and convenient method to investigate the secondary structure and interactions of biomolecules. Recent advancements in CD spectroscopy have enabled the study of DNA-protein interactions and conformational dynamics of DNA in different microenvironments in detail for a better understanding of transcriptional regulation in vivo. The area around a potential transcription zone needs to be unwound for transcription to occur. This is a complex process requiring the coordination of histone modifications, binding of the transcription factor to DNA, and other chromatin remodeling activities. Using CD spectroscopy, it is possible to study conformational changes in the promoter region caused by regulatory proteins, such as ATP-dependent chromatin remodelers, to promote transcription. The conformational changes occurring in the protein can also be monitored. In addition, queries regarding the affinity of the protein towards its target DNA and sequence specificity can be addressed by incorporating mutations in the target DNA. In short, the unique understanding of this sensitive and inexpensive method can predict changes in chromatin dynamics, thereby improving the understanding of transcriptional regulation.

The interaction of an ATP-dependent chromatin remodeler with a DNA ligand is described using CD spectroscopy. The induced conformational changes on a gene promoter analyzed by the peaks generated can be used to understand the mechanism of transcriptional regulation.

DNA 단백질 상호 작용을 연구하는 CD 분광법

Circular dichroism (CD) spectroscopy is a simple and convenient method to investigate the secondary structure and interactions of biomolecules. Recent ...

생화학

Chromatin Interaction Analysis with Paired-End Tag Sequencing (ChIA-PET) for Mapping Chromatin Interactions and Understanding Transcription Regulation

Genomes are organized into three-dimensional structures, adopting higher-order conformations inside the micron-sized nuclear spaces 7, 2, 12. Such architectures are not random and involve interactions between gene promoters and regulatory elements 13. The binding of transcription factors to specific regulatory sequences brings about a network of transcription regulation and coordination 1, 14. 
Chromatin Interaction Analysis by Paired-End Tag Sequencing (ChIA-PET) was developed to identify these higher-order chromatin structures 5,6. Cells are fixed and interacting loci are captured by covalent DNA-protein cross-links. To minimize non-specific noise and reduce complexity, as well as to increase the specificity of the chromatin interaction analysis, chromatin immunoprecipitation (ChIP) is used against specific protein factors to enrich chromatin fragments of interest before proximity ligation. Ligation involving half-linkers subsequently forms covalent links between pairs of DNA fragments tethered together within individual chromatin complexes. The flanking MmeI restriction enzyme sites in the half-linkers allow extraction of paired end tag-linker-tag constructs (PETs) upon MmeI digestion. As the half-linkers are biotinylated, these PET constructs are purified using streptavidin-magnetic beads. The purified PETs are ligated with next-generation sequencing adaptors and a catalog of interacting fragments is generated via next-generation sequencers such as the Illumina Genome Analyzer. Mapping and bioinformatics analysis is then performed to identify ChIP-enriched binding sites and ChIP-enriched chromatin interactions 8. 
We have produced a video to demonstrate critical aspects of the ChIA-PET protocol, especially the preparation of ChIP as the quality of ChIP plays a major role in the outcome of a ChIA-PET library. As the protocols are very long, only the critical steps are shown in the video.

Chromatin Interaction Analysis with Paired-End Tag Sequencing ChIA-PET for Mapping Chromatin Interactions and Understanding Transcription Regulation

Chromatin Interaction Analysis by Paired-End Tag Sequencing (ChIA-PET) is a method for de novo detection of chromatin interactions, for better understanding of transcriptional control.

염색질 상호 작용을 매핑 및 전사 규정을 이해하는 데 이점 엔드 태그 장면 (ChIA-PET)과 염색질의 상호 작용 분석

Genomes are organized into three-dimensional structures, adopting higher-order conformations inside the micron-sized nuclear spaces 7, 2, 12. Such ...

생물학

Identification of Protein Interaction Partners in Mammalian Cells Using SILAC-immunoprecipitation Quantitative Proteomics

Quantitative proteomics combined with immuno-affinity purification, SILAC immunoprecipitation, represent a powerful means for the discovery of novel protein:protein interactions. By allowing the accurate relative quantification of protein abundance in both control and test samples, true interactions may be easily distinguished from experimental contaminants. Low affinity interactions can be preserved through the use of less-stringent buffer conditions and remain readily identifiable. This protocol discusses the labeling of tissue culture cells with stable isotope labeled amino acids, transfection and immunoprecipitation of an affinity tagged protein of interest, followed by the preparation for submission to a mass spectrometry facility. This protocol then discusses how to analyze and interpret the data returned from the mass spectrometer in order to identify cellular partners interacting with a protein of interest. As an example this technique is applied to identify proteins binding to the eukaryotic translation initiation factors: eIF4AI and eIF4AII.

SILAC immunoprecipitation experiments represent a powerful means for discovering novel protein:protein interactions. By allowing the accurate relative quantification of protein abundance in both control and test samples, true interactions may be easily distinguished from experimental contaminants, and low affinity interactions preserved through use of less-stringent buffer conditions.

SILAC - 면역 정량 프로테오믹스를 사용하여 포유 동물 세포에있는 단백질 상호 작용 파트너의 식별

Quantitative proteomics combined with immuno-affinity purification, SILAC immunoprecipitation, represent a powerful means for the discovery of novel ...

DNA-affinity-purified Chip (DAP-chip) Method to Determine Gene Targets for Bacterial Two component Regulatory Systems

In vivo methods such as ChIP-chip are well-established techniques used to determine global gene targets for transcription factors. However, they are of limited use in exploring bacterial two component regulatory systems with uncharacterized activation conditions. Such systems regulate transcription only when activated in the presence of unique signals. Since these signals are often unknown, the in vitro microarray based method described in this video article can be used to determine gene targets and binding sites for response regulators. This DNA-affinity-purified-chip method may be used for any purified regulator in any organism with a sequenced genome. The protocol involves allowing the purified tagged protein to bind to sheared genomic DNA and then affinity purifying the protein-bound DNA, followed by fluorescent labeling of the DNA and hybridization to a custom tiling array. Preceding steps that may be used to optimize the assay for specific regulators are also described. The peaks generated by the array data analysis are used to predict binding site motifs, which are then experimentally validated. The motif predictions can be further used to determine gene targets of orthologous response regulators in closely related species. We demonstrate the applicability of this method by determining the gene targets and binding site motifs and thus predicting the function for a sigma54-dependent response regulator DVU3023 in the environmental bacterium Desulfovibrio vulgaris Hildenborough.

DNA-affinity-purified Chip DAP-chip Method to Determine Gene Targets for Bacterial Two component Regulatory Systems

This video article describes an in vitro microarray based method to determine the gene targets and binding sites for two component system response regulators.

세균에 대한 두 개의 구성 요소 규제 시스템을 유전자 표적을 확인하는 DNA 친화력 - 정제 칩 (DAP-칩) 방법

In vivo methods such as ChIP-chip are well-established techniques used to determine global gene targets for transcription factors. However, they are of ...

Genome-wide Mapping of Drug-DNA Interactions in Cells with COSMIC (Crosslinking of Small Molecules to Isolate Chromatin)

The genome is the target of some of the most effective chemotherapeutics, but most of these drugs lack DNA sequence specificity, which leads to dose-limiting toxicity and many adverse side effects. Targeting the genome with sequence-specific small molecules may enable molecules with increased therapeutic index and fewer off-target effects. N-methylpyrrole/N-methylimidazole polyamides are molecules that can be rationally designed to target specific DNA sequences with exquisite precision. And unlike most natural transcription factors, polyamides can bind to methylated and chromatinized DNA without a loss in affinity. The sequence specificity of polyamides has been extensively studied in vitro with cognate site identification (CSI) and with traditional biochemical and biophysical approaches, but the study of polyamide binding to genomic targets in cells remains elusive. Here we report a method, the crosslinking of small molecules to isolate chromatin (COSMIC), that identifies polyamide binding sites across the genome. COSMIC is similar to chromatin immunoprecipitation (ChIP), but differs in two important ways: (1) a photocrosslinker is employed to enable selective, temporally-controlled capture of polyamide binding events, and (2) the biotin affinity handle is used to purify polyamide&#8211;DNA conjugates under semi-denaturing conditions to decrease DNA that is non-covalently bound. COSMIC is a general strategy that can be used to reveal the genome-wide binding events of polyamides and other genome-targeting chemotherapeutic agents.

Genome-wide Mapping of Drug-DNA Interactions in Cells with COSMIC Crosslinking of Small Molecules to Isolate Chromatin

Identifying the direct targets of genome-targeting molecules remains a major challenge. To understand how DNA-binding molecules engage the genome, we developed a method that relies on crosslinking of small molecules to isolate chromatin (COSMIC).

COSMIC와 세포의 약물-DNA 상호 작용의 게놈 넓은 매핑 (작은 분자의 가교는 염색질을 분리)

The genome is the target of some of the most effective chemotherapeutics, but most of these drugs lack DNA sequence specificity, which leads to ...

In Situ Monitoring of Transiently Formed Molecular Chaperone Assemblies in Bacteria, Yeast, and Human Cells

J-domain proteins (JDPs) form the largest and the most diverse co-chaperone family in eukaryotic cells. Recent findings show that specific members of the JDP family could form transient heterocomplexes in eukaryotes to fine-tune substrate selection for the 70 kDa heat shock protein (Hsp70) chaperone-based protein disaggregases. The JDP complexes target acute/chronic stress induced aggregated proteins and presumably help assemble the disaggregases by recruiting multiple Hsp70s to the surface of protein aggregates. The extent of the protein quality control (PQC) network formed by these physically interacting JDPs remains largely uncharacterized in vivo. Here, we describe a microscopy-based in situ protein interaction assay named the proximity ligation assay (PLA), which is able to robustly capture&#160;these transiently formed chaperone complexes in distinct cellular compartments of eukaryotic cells. Our work expands the employment of PLA from human cells to yeast (Saccharomyces cerevisiae) and bacteria (Escherichia coli), thus rendering an important tool to monitor the dynamics of transiently formed protein assemblies in both prokaryotic and eukaryotic cells.

Cognate J-domain proteins cooperate with the Hsp70 chaperone to assist in a myriad of biological processes ranging from protein folding to degradation. Here, we describe an in situ proximity ligation assay, which allows the monitoring of these transiently formed chaperone machineries in bacterial, yeast and human cells.

박테리아, 효모 및 인간 세포에서 일시적으로 형성된 분자 샤페론 어셈블리의 시투 모니터링

J-domain proteins (JDPs) form the largest and the most diverse co-chaperone family in eukaryotic cells. Recent findings show that specific members of the ...

Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage

Cells are continuously exposed to various DNA damaging agents, inducing different cellular responses. Applying biochemical and genetic approaches is essential in revealing cellular events associated with the recruitment and assembly of DNA repair complexes at the site of DNA damage. In the last few years, several powerful tools have been developed to induce site-specific DNA damage. Moreover, novel seminal techniques allow us to study these processes at the single-cell resolution level using both fixed and living cells. Although these techniques have been used to study various biological processes, herein we present the most widely used protocols in the field of DNA repair, Fluorescence Immunostaining (IF) and Chromatin Immunoprecipitation (ChIP), which in combination with endonuclease-based site-specific DNA damage make it possible to visualize and quantify the genomic occupancy of DNA repair factors in a directed and regulated fashion, respectively. These techniques provide powerful tools for the researchers to identify novel proteins bound to the damaged genomic locus as well as their post-translational modifications necessary for their fine-tune regulation during DNA repair.

This article introduces essential steps of immunostaining and chromatin immunoprecipitation. These protocols are commonly used to study DNA damage-related cellular processes and to visualize and quantify the recruitment of proteins implicated in DNA repair.

엔도누블레스 기반 사이트 별 DNA 손상을 시각화하고 정량화

Cells are continuously exposed to various DNA damaging agents, inducing different cellular responses. Applying biochemical and genetic approaches is ...