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Chavali K, Coker H, Youngblood E, Karaduta O. Proteogenomics in Nephrology: A New Frontier in Nephrological Research. Curr Issues Mol Biol 2024; 46:4595-4608. [PMID: 38785547 PMCID: PMC11120334 DOI: 10.3390/cimb46050279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/03/2024] [Accepted: 05/05/2024] [Indexed: 05/25/2024] Open
Abstract
Proteogenomics represents a transformative intersection in nephrology, uniting genomics, transcriptomics, and proteomics to unravel the molecular intricacies of kidney diseases. This review encapsulates the methodological essence of proteogenomics and its profound implications in chronic kidney disease (CKD) research. We explore the proteogenomic pipeline, highlighting the integrated analysis of genomic, transcriptomic, and proteomic data and its pivotal role in enhancing our understanding of kidney pathologies. Through case studies, we showcase the application of proteogenomics in clear cell renal cell carcinoma (ccRCC) and Autosomal Recessive Polycystic Kidney Disease (ARPKD), emphasizing its potential in personalized treatment strategies and biomarker discovery. The review also addresses the challenges in proteogenomic analysis, including data integration complexities and bioinformatics limitations, and proposes solutions for advancing the field. Ultimately, this review underscores the prospective future of proteogenomics in nephrology, particularly in advancing personalized medicine and providing novel therapeutic insights.
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Affiliation(s)
- Kavya Chavali
- Adventist Health Hanford Family Medicine Residency Program, ONE Adventist Health Way, Roseville, CA 95661, USA
| | - Holley Coker
- Department of Physician Assistant Studies, University of Arkansas for Medical Sciences, 4301 W Markham Street, Little Rock, AR 72205, USA
| | - Emily Youngblood
- Department of Physician Assistant Studies, University of Arkansas for Medical Sciences, 4301 W Markham Street, Little Rock, AR 72205, USA
| | - Oleg Karaduta
- Department of Physician Assistant Studies, University of Arkansas for Medical Sciences, 4301 W Markham Street, Little Rock, AR 72205, USA
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2
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MacKenzie TMG, Cisneros R, Maynard RD, Snyder MP. Reverse-ChIP Techniques for Identifying Locus-Specific Proteomes: A Key Tool in Unlocking the Cancer Regulome. Cells 2023; 12:1860. [PMID: 37508524 PMCID: PMC10377898 DOI: 10.3390/cells12141860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/30/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
A phenotypic hallmark of cancer is aberrant transcriptional regulation. Transcriptional regulation is controlled by a complicated array of molecular factors, including the presence of transcription factors, the deposition of histone post-translational modifications, and long-range DNA interactions. Determining the molecular identity and function of these various factors is necessary to understand specific aspects of cancer biology and reveal potential therapeutic targets. Regulation of the genome by specific factors is typically studied using chromatin immunoprecipitation followed by sequencing (ChIP-Seq) that identifies genome-wide binding interactions through the use of factor-specific antibodies. A long-standing goal in many laboratories has been the development of a 'reverse-ChIP' approach to identify unknown binding partners at loci of interest. A variety of strategies have been employed to enable the selective biochemical purification of sequence-defined chromatin regions, including single-copy loci, and the subsequent analytical detection of associated proteins. This review covers mass spectrometry techniques that enable quantitative proteomics before providing a survey of approaches toward the development of strategies for the purification of sequence-specific chromatin as a 'reverse-ChIP' technique. A fully realized reverse-ChIP technique holds great potential for identifying cancer-specific targets and the development of personalized therapeutic regimens.
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Affiliation(s)
| | - Rocío Cisneros
- Sarafan ChEM-H/IMA Postbaccalaureate Fellow in Target Discovery, Stanford University, Stanford, CA 94305, USA
| | - Rajan D Maynard
- Genetics Department, Stanford University, Stanford, CA 94305, USA
| | - Michael P Snyder
- Genetics Department, Stanford University, Stanford, CA 94305, USA
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3
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Li C, Mori LP, Lyu S, Bronson R, Getzler AJ, Pipkin ME, Valente ST. The chaperone protein p32 stabilizes HIV-1 Tat and strengthens the p-TEFb/RNAPII/TAR complex promoting HIV transcription elongation. Proc Natl Acad Sci U S A 2023; 120:e2217476120. [PMID: 36584296 PMCID: PMC9910500 DOI: 10.1073/pnas.2217476120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/29/2022] [Indexed: 12/31/2022] Open
Abstract
HIV gene expression is modulated by the combinatorial activity of the HIV transcriptional activator, Tat, host transcription factors, and chromatin remodeling complexes. To identify host factors regulating HIV transcription, we used specific single-guide RNAs and endonuclease-deficient Cas9 to perform chromatin affinity purification of the integrated HIV promoter followed by mass spectrometry. The scaffold protein, p32, also called ASF/SF2 splicing factor-associated protein, was identified among the top enriched factors present in actively transcribing HIV promoters but absent in silenced ones. Chromatin immunoprecipitation analysis confirmed the presence of p32 on active HIV promoters and its enhanced recruitment by Tat. HIV uses Tat to efficiently recruit positive transcription elongation factor b (p-TEFb) (CDK9/CCNT1) to TAR, an RNA secondary structure that forms from the first 59 bp of HIV transcripts, to enhance RNAPII transcriptional elongation. The RNA interference of p32 significantly reduced HIV transcription in primary CD4+T cells and in HIV chronically infected cells, independently of either HIV splicing or p32 anti-splicing activity. Conversely, overexpression of p32 specifically increased Tat-dependent HIV transcription. p32 was found to directly interact with Tat's basic domain enhancing Tat stability and half-life. Conversely, p32 associates with Tat via N- and C-terminal domains. Likely due its scaffold properties, p32 also promoted Tat association with TAR, p-TEFb, and RNAPII enhancing Tat-dependent HIV transcription. In sum, we identified p32 as a host factor that interacts with and stabilizes Tat protein, promotes Tat-dependent transcriptional regulation, and may be explored for HIV-targeted transcriptional inhibition.
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Affiliation(s)
- Chuan Li
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
| | - Luisa P. Mori
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
- The Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL33458
| | - Shuang Lyu
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
| | - Ronald Bronson
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
| | - Adam J. Getzler
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
- The Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL33458
| | - Matthew E. Pipkin
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
- The Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL33458
| | - Susana T. Valente
- Department of Immunology and Microbiology, University of Florida Scripps Biomedical Research, Jupiter, FL33458
- The Skaggs Graduate School, The Scripps Research Institute, Jupiter, FL33458
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4
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Mondal S, Ramanathan M, Miao W, Meyers RM, Rao D, Lopez-Pajares V, Siprashvili Z, Reynolds DL, Porter DF, Ferguson I, Neela P, Zhao Y, Meservey LM, Guo M, Yang YY, Li L, Wang Y, Khavari PA. PROBER identifies proteins associated with programmable sequence-specific DNA in living cells. Nat Methods 2022; 19:959-968. [PMID: 35927480 PMCID: PMC10202087 DOI: 10.1038/s41592-022-01552-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/20/2022] [Indexed: 11/08/2022]
Abstract
DNA-protein interactions mediate physiologic gene regulation and may be altered by DNA variants linked to polygenic disease. To enhance the speed and signal-to-noise ratio (SNR) in the identification and quantification of proteins associated with specific DNA sequences in living cells, we developed proximal biotinylation by episomal recruitment (PROBER). PROBER uses high-copy episomes to amplify SNR, and proximity proteomics (BioID) to identify the transcription factors and additional gene regulators associated with short DNA sequences of interest. PROBER quantified both constitutive and inducible association of transcription factors and corresponding chromatin regulators to target DNA sequences and binding quantitative trait loci due to single-nucleotide variants. PROBER identified alterations in regulator associations due to cancer hotspot mutations in the hTERT promoter, indicating that these mutations increase promoter association with specific gene activators. PROBER provides an approach to rapidly identify proteins associated with specific DNA sequences and their variants in living cells.
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Affiliation(s)
- Smarajit Mondal
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | | | - Weili Miao
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | - Robin M Meyers
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | - Deepti Rao
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | | | - Zurab Siprashvili
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | - David L Reynolds
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | - Douglas F Porter
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | - Ian Ferguson
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | - Poornima Neela
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | - Yang Zhao
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
| | | | - Margaret Guo
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA
- Program in Biomedical Informatics, Stanford University, Stanford, CA, USA
| | - Yen-Yu Yang
- Department of Chemistry, University of California, Riverside, CA, USA
| | - Lin Li
- Department of Chemistry, University of California, Riverside, CA, USA
| | - Yinsheng Wang
- Department of Chemistry, University of California, Riverside, CA, USA
| | - Paul A Khavari
- Program in Epithelial Biology, Stanford University, Stanford, CA, USA.
- Stanford Cancer Institute, Stanford University, Stanford, CA, USA.
- Veterans Affairs, Palo Alto Healthcare System, Palo Alto, CA, USA.
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5
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Knaupp AS, Mohenska M, Larcombe MR, Ford E, Lim SM, Wong K, Chen J, Firas J, Huang C, Liu X, Nguyen T, Sun YBY, Holmes ML, Tripathi P, Pflueger J, Rossello FJ, Schröder J, Davidson KC, Nefzger CM, Das PP, Haigh JJ, Lister R, Schittenhelm RB, Polo JM. TINC- A Method to Dissect Regulatory Complexes at Single-Locus Resolution- Reveals an Extensive Protein Complex at the Nanog Promoter. Stem Cell Reports 2020; 15:1246-1259. [PMID: 33296673 PMCID: PMC7724517 DOI: 10.1016/j.stemcr.2020.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/08/2020] [Accepted: 11/09/2020] [Indexed: 12/16/2022] Open
Abstract
Cellular identity is ultimately dictated by the interaction of transcription factors with regulatory elements (REs) to control gene expression. Advances in epigenome profiling techniques have significantly increased our understanding of cell-specific utilization of REs. However, it remains difficult to dissect the majority of factors that interact with these REs due to the lack of appropriate techniques. Therefore, we developed TINC: TALE-mediated isolation of nuclear chromatin. Using this new method, we interrogated the protein complex formed at the Nanog promoter in embryonic stem cells (ESCs) and identified many known and previously unknown interactors, including RCOR2. Further interrogation of the role of RCOR2 in ESCs revealed its involvement in the repression of lineage genes and the fine-tuning of pluripotency genes. Consequently, using the Nanog promoter as a paradigm, we demonstrated the power of TINC to provide insight into the molecular makeup of specific transcriptional complexes at individual REs as well as into cellular identity control in general. TINC allows the isolation of a specific locus for molecular analyses TINC identified hundreds of proteins at the Nanog promoter RCOR2 is a component of the pluripotency network in embryonic stem cells RCOR2 is required for efficient differentiation
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Affiliation(s)
- Anja S Knaupp
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Monika Mohenska
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Michael R Larcombe
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Ethan Ford
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, WA 6009, Australia; Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia
| | - Sue Mei Lim
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Kayla Wong
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Joseph Chen
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Jaber Firas
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Cheng Huang
- Monash Proteomics and Metabolomics Facility, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Xiaodong Liu
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Trung Nguyen
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, WA 6009, Australia; Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia
| | - Yu B Y Sun
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Melissa L Holmes
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Pratibha Tripathi
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia
| | - Jahnvi Pflueger
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, WA 6009, Australia; Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia
| | - Fernando J Rossello
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Jan Schröder
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Kathryn C Davidson
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Christian M Nefzger
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia
| | - Partha P Das
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia
| | - Jody J Haigh
- Australian Centre for Blood Diseases, Monash University, Clayton, VIC 3004, Australia; Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada; Research Institute in Oncology and Hematology, CancerCare Manitoba, Winnipeg, MB, Canada
| | - Ryan Lister
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Perth, WA 6009, Australia; Harry Perkins Institute of Medical Research, Nedlands, WA 6009, Australia
| | - Ralf B Schittenhelm
- Monash Proteomics and Metabolomics Facility, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia.
| | - Jose M Polo
- Department of Anatomy and Developmental Biology, Monash University, Clayton, VIC 3800, Australia; Development and Stem Cells Program, Monash Biomedicine Discovery Institute, Clayton, VIC 3800, Australia; Australian Regenerative Medicine Institute, Monash University, Clayton, VIC 3800, Australia.
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6
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Waldrip ZJ, Jenjaroenpun P, DeYoung O, Nookaew I, Taverna SD, Raney KD, Tackett AJ. Genome-wide Cas9 binding specificity in Saccharomyces cerevisiae. PeerJ 2020; 8:e9442. [PMID: 32821531 PMCID: PMC7395602 DOI: 10.7717/peerj.9442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 06/08/2020] [Indexed: 12/26/2022] Open
Abstract
The CRISPR system has become heavily utilized in biomedical research as a tool for genomic editing as well as for site-specific chromosomal localization of specific proteins. For example, we developed a CRISPR-based methodology for enriching a specific genomic locus of interest for proteomic analysis in Saccharomyces cerevisiae, which utilized a guide RNA-targeted, catalytically dead Cas9 (dCas9) as an affinity reagent. To more comprehensively evaluate the genomic specificity of using dCas9 as a site-specific tool for chromosomal studies, we performed dCas9-mediated locus enrichment followed by next-generation sequencing on a genome-wide scale. As a test locus, we used the ARS305 origin of replication on chromosome III in S. cerevisiae. We found that enrichment of this site is highly specific, with virtually no off-target enrichment of unique genomic sequences. The high specificity of genomic localization and enrichment suggests that dCas9-mediated technologies have promising potential for site-specific chromosomal studies in organisms with relatively small genomes such as yeasts.
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Affiliation(s)
- Zachary J Waldrip
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
| | - Piroon Jenjaroenpun
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
| | - Oktawia DeYoung
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
| | - Intawat Nookaew
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
| | - Sean D Taverna
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD, United States of America
| | - Kevin D Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
| | - Alan J Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
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7
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Huang Y, Xiang Y, Xie Z, Cai Y, Yang Q, Huang H, Chen Z, Xiao Z, He Q. Mass spectrometry-based proteomic capture of proteins bound to the MACC1 promoter in colon cancer. Clin Exp Metastasis 2020; 37:477-487. [PMID: 32613480 DOI: 10.1007/s10585-020-10045-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 06/07/2020] [Indexed: 12/20/2022]
Abstract
MACC1 (metastasis associated in colon cancer 1) is a key driver that induces metastasis in colon cancer. However, the mechanisms by which MACC1 expression is transcriptionally regulated and the factors enriched at the MACC1 promoter remain largely unknown. The binding of proteins to specific DNA sites in the genome is a major determinant of genomic maintenance and the regulation of specific genes. The study herein utilized two methods to study the binding proteins of the MACC1 promoter region in colon cancer. Specifically, we adopted CRISPR-based chromatin affinity purification with mass spectrometry (CRISPR-ChAP-MS) and a biotin-streptavidin pulldown assay coupled with MS to identify the specific proteome bound to the MACC1 promoter in two colon cell lines with different metastatic potential. A total of 24 proteins were identified by CRISPR-ChAP-MS as binding to the MACC1 promoter, among which c-JUN was validated by ChIP-PCR. A total of 739 binding protein candidates were identified by biotin-streptavidin pulldown assays coupled with MS, of which HNF4G and PAX6 were validated and compared for their binding to the same promoter sites in the two cell lines. Our studies suggest distinctive proteomic factors associated with the MACC1 promoter in colon cells with different metastatic potential. The dynamic regulatory factors accumulated at the promoter of MACC1 may provide novel insights into the regulatory mechanisms of MACC1 transcription.
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Affiliation(s)
- Yahui Huang
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.,School of Basic Medical Sciences, Central South University, Changsha, Hunan, People's Republic of China.,Department of Pathology, Xuchang Central Hospital, Henan University of Science and Technology, Xuchang, Henan, People's Republic of China
| | - Yi Xiang
- School of Basic Medical Sciences, Central South University, Changsha, Hunan, People's Republic of China
| | - Zhongpeng Xie
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.,School of Basic Medical Sciences, Central South University, Changsha, Hunan, People's Republic of China.,Department of Pathology, Hainan General Hospital, Haikou, Hainan, People's Republic of China
| | - Yuxiang Cai
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.,School of Basic Medical Sciences, Central South University, Changsha, Hunan, People's Republic of China
| | - Qiongzhi Yang
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.,School of Basic Medical Sciences, Central South University, Changsha, Hunan, People's Republic of China
| | - Huichao Huang
- NHC Key Laboratory of Cancer Proteomics, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
| | - Zhuchu Chen
- NHC Key Laboratory of Cancer Proteomics, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China
| | - Zhefeng Xiao
- NHC Key Laboratory of Cancer Proteomics, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China.
| | - Qiongqiong He
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China. .,School of Basic Medical Sciences, Central South University, Changsha, Hunan, People's Republic of China.
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8
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Purification and enrichment of specific chromatin loci. Nat Methods 2020; 17:380-389. [PMID: 32152500 DOI: 10.1038/s41592-020-0765-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/29/2020] [Indexed: 12/20/2022]
Abstract
Understanding how chromatin is regulated is essential to fully grasp genome biology, and establishing the locus-specific protein composition is a major step toward this goal. Here we explain why the isolation and analysis of a specific chromatin segment are technically challenging, independently of the method. We then describe the published strategies and discuss their advantages and limitations. We conclude by discussing why significant technology developments are required to unambiguously describe the composition of small single loci.
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9
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Anderson JT, Rogers JM, Barrera LA, Bulyk ML. Context and number of noncanonical repeat variable diresidues impede the design of TALE proteins with improved DNA targeting. Protein Sci 2019; 29:606-616. [PMID: 31833142 DOI: 10.1002/pro.3801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/27/2019] [Accepted: 12/02/2019] [Indexed: 12/18/2022]
Abstract
Transcription activator-like effector (TALE) proteins have been used extensively for targeted binding of fusion proteins to loci of interest in (epi)genome engineering. Such approaches typically utilize four canonical TALE repeat variable diresidue (RVD) types, corresponding to the identities of two key amino acids, to target each nucleotide. Alternate RVDs with improved specificity are desired. Here, we focused on seven noncanonical RVDs that have been suggested to have improved specificity for their target nucleotides. We used custom protein binding microarrays to characterize the DNA-binding activity of 65 TALEs containing these alternate or corresponding canonical RVDs at multiple positions to ~5,000 unique DNA sequences per protein. We found that none of the noncanonical thymine-targeting RVDs displayed stronger preference for thymine than did the canonical RVD. Of the noncanonical RVDs with putatively improved specificity for guanine, only EN and NH showed greater discrimination of guanine over adenine. This improved specificity, however, comes at a cost: more substitutions of a noncanonical RVD for a canonical RVD generally decreased the protein's DNA-binding activity. Our results highlight the need to investigate RVD-nucleotide specificities in multiple protein contexts and suggest that a balance between canonical and noncanonical RVDs is needed to build TALEs with improved specificity.
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Affiliation(s)
- James T Anderson
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Julia M Rogers
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts
| | - Luis A Barrera
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts.,Harvard-MIT Division of Health Sciences and Technology (HST), Harvard Medical School, Boston, Massachusetts
| | - Martha L Bulyk
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.,Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts.,Harvard-MIT Division of Health Sciences and Technology (HST), Harvard Medical School, Boston, Massachusetts.,Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
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10
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Jensen IS, Yuan J, He J, Lin L, Sander B, Golas MM. The FlpTRAP system for purification of specific, endogenous chromatin regions. Anal Biochem 2019; 587:113418. [PMID: 31520595 DOI: 10.1016/j.ab.2019.113418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 09/07/2019] [Accepted: 09/08/2019] [Indexed: 10/26/2022]
Abstract
The repressor element 1-silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF) binds to repressor element 1/neuron-restrictive silencer element (RE1/NRSE) sites in the genome and recruits effector proteins to repress its target genes. Here, we developed the FlpTRAP system to isolate endogenously assembled DNA-protein complexes such as the REST/NRSF complex. In the FlpTRAP system, we take advantage of the step-arrest variant of the Flp recombinase, FlpH305L, which, in the presence of Flp recognition target (FRT) DNA, accumulates as FRT DNA-protein adduct. The FlpTRAP system consists of three elements: (i) FlpH305L-containing cell extracts or isolates, (ii) a cell line engineered to harbor the DNA motif of interest flanked by FRT sites, and (iii) affinity selection steps to isolate the target chromatin. Specifically, 3×FLAG-tagged FlpH305L was expressed in insect cell cultures infected with baculovirus, and cell lysates were prepared. The lysate was used to capture the FRT-SNAP25 RE1/NRSE-FRT chromatin from a human medulloblastoma cell line, and the target RE1/NRSE chromatin was isolated by anti-FLAG immunoaffinity chromatography. Using electrophoretic mobility shift assays (EMSAs) and chromatin immunopurification (ChIP), we show that FlpH305L recognized and bound to the FRT sites. Overall, we suggest the FlpTRAP system as a tool to purify endogenous, specific chromatin loci from eukaryotic cells.
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Affiliation(s)
- Ida S Jensen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Juan Yuan
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Jin He
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Lin Lin
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Bjoern Sander
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark
| | - Monika M Golas
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 3, Building 1233, 8000, Aarhus C, Denmark.
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11
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Qiu W, Xu Z, Zhang M, Zhang D, Fan H, Li T, Wang Q, Liu P, Zhu Z, Du D, Tan M, Wen B, Liu Y. Determination of local chromatin interactions using a combined CRISPR and peroxidase APEX2 system. Nucleic Acids Res 2019; 47:e52. [PMID: 30805613 PMCID: PMC6511869 DOI: 10.1093/nar/gkz134] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 01/15/2019] [Accepted: 02/19/2019] [Indexed: 01/10/2023] Open
Abstract
The architecture and function of chromatin are largely regulated by local interacting molecules, such as transcription factors and noncoding RNAs. However, our understanding of these regulatory molecules at a given locus is limited because of technical difficulties. Here, we describe the use of Clustered Regularly Interspaced Short Palindromic Repeats and an engineered ascorbate peroxidase 2 (APEX2) system to investigate local chromatin interactions (CAPLOCUS). We showed that with specific small-guide RNA targets, CAPLOCUS could efficiently identify both repetitive genomic regions and single-copy genomic locus with high resolution. Genome-wide sequencing revealed known and potential long-range chromatin interactions for a specific single-copy locus. CAPLOCUS also identified telomere-associated RNAs. CAPLOCUS, followed by mass spectrometry, identified both known and novel telomere-associated proteins in their native states. Thus, CAPLOCUS may be a useful approach for studying local interacting molecules at any given chromosomal location.
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Affiliation(s)
- Wenqing Qiu
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China, 200032
| | - Zhijiao Xu
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China, 200032
| | - Min Zhang
- The Chemical Proteomics Center and State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China, 201203
| | - Dandan Zhang
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China, 200032
| | - Hui Fan
- MOE Key Laboratory of Metabolism and Molecular Medicine, Institutes of Biomedical Sciences, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China, 200032
| | - Taotao Li
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China, 200032
| | - Qianfeng Wang
- MOE Key Laboratory of Metabolism and Molecular Medicine, Institutes of Biomedical Sciences, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China, 200032
| | - Peiru Liu
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China, 200032
| | - Zaihua Zhu
- Division of Rheumatology, Huashan Hospital, Fudan University, Shanghai, China, 200040
| | - Duo Du
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China, 200032
| | - Minjia Tan
- The Chemical Proteomics Center and State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China, 201203
| | - Bo Wen
- MOE Key Laboratory of Metabolism and Molecular Medicine, Institutes of Biomedical Sciences, and Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai, China, 200032
| | - Yun Liu
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Zhongshan Hospital, Fudan University, Shanghai, China, 200032
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12
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Kang SK, Chu XY, Tian T, Dong PF, Chen BX, Zhang HY. Why the c-Fos/c-Jun complex is extremely conserved: An in vitro evolution exploration by combining cDNA display and proximity ligation. FEBS Lett 2019; 593:1040-1049. [PMID: 31002393 DOI: 10.1002/1873-3468.13388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/31/2019] [Accepted: 04/10/2019] [Indexed: 11/08/2022]
Abstract
Transcriptional regulation involves a series of sophisticated protein-protein and protein-DNA interactions (PPI and PDI). Some transcriptional complexes, such as c-Fos/c-Jun and their binding DNA fragments, have been conserved over the past one billion years. Considering the thermodynamic principle for transcriptional complex formation, we hypothesized that the c-Fos/c-Jun complex may represent a thermodynamic summit in the evolutionary space. To test this, we invented a new method, termed One-Pot-seq, which combines cDNA display and proximity ligation to analyse PPI/PDI complexes simultaneously. We found that the wild-type c-Fos/c-Jun complex is indeed the most thermodynamically stable relative to various mutants of c-Fos/c-Jun and binding DNA fragments. Our method also provides a universal approach to detect transcriptional complexes and explore transcriptional regulation mechanisms.
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Affiliation(s)
- Shou-Kai Kang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
| | - Xin-Yi Chu
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
| | - Tian Tian
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
| | - Peng-Fei Dong
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
| | - Bai-Xue Chen
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
| | - Hong-Yu Zhang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, China
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13
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West KL, Byrum SD, Mackintosh SG, Edmondson RD, Taverna SD, Tackett AJ. Proteomic characterization of the arsenic response locus in S. cerevisiae. Epigenetics 2019; 14:130-145. [PMID: 30739529 PMCID: PMC6557609 DOI: 10.1080/15592294.2019.1580110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 01/17/2019] [Accepted: 01/21/2019] [Indexed: 10/27/2022] Open
Abstract
Arsenic exposure is a global health problem. Millions of people encounter arsenic through contaminated drinking water, consumption, and inhalation. The arsenic response locus in budding yeast is responsible for the detoxification of arsenic and its removal from the cell. This locus constitutes a conserved pathway ranging from prokaryotes to higher eukaryotes. The goal of this study was to identify how transcription from the arsenic response locus is regulated in an arsenic dependent manner. An affinity enrichment strategy called CRISPR-Chromatin Affinity Purification with Mass Spectrometry (CRISPR-ChAP-MS) was used, which provides for the proteomic characterization of a targeted locus. CRISPR-ChAP-MS was applied to the promoter regions of the activated arsenic response locus and uncovered 40 nuclear-annotated proteins showing enrichment. Functional assays identified the histone acetyltransferase SAGA and the chromatin remodelling complex SWI/SNF to be required for activation of the locus. Furthermore, SAGA and SWI/SNF were both found to specifically organize the chromatin structure at the arsenic response locus for activation of gene transcription. This study provides the first proteomic characterization of an arsenic response locus and key insight into the mechanisms of transcriptional activation that are necessary for detoxification of arsenic from the cell.
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Affiliation(s)
- Kirk L. West
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Stephanie D. Byrum
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Arkansas Children’s Research Institute, Little Rock, AR, USA
| | - Samuel G. Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Rick D. Edmondson
- College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Sean D. Taverna
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Epigenetics, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Alan J. Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Arkansas Children’s Research Institute, Little Rock, AR, USA
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14
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A distinct isoform of ZNF207 controls self-renewal and pluripotency of human embryonic stem cells. Nat Commun 2018; 9:4384. [PMID: 30349051 PMCID: PMC6197280 DOI: 10.1038/s41467-018-06908-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 09/21/2018] [Indexed: 01/08/2023] Open
Abstract
Self-renewal and pluripotency in human embryonic stem cells (hESCs) depends upon the function of a remarkably small number of master transcription factors (TFs) that include OCT4, SOX2, and NANOG. Endogenous factors that regulate and maintain the expression of master TFs in hESCs remain largely unknown and/or uncharacterized. Here, we use a genome-wide, proteomics approach to identify proteins associated with the OCT4 enhancer. We identify known OCT4 regulators, plus a subset of potential regulators including a zinc finger protein, ZNF207, that plays diverse roles during development. In hESCs, ZNF207 partners with master pluripotency TFs to govern self-renewal and pluripotency while simultaneously controlling commitment of cells towards ectoderm through direct regulation of neuronal TFs, including OTX2. The distinct roles of ZNF207 during differentiation occur via isoform switching. Thus, a distinct isoform of ZNF207 functions in hESCs at the nexus that balances pluripotency and differentiation to ectoderm.
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15
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Liu X, Zhang Y, Chen Y, Li M, Shao Z, Zhang MQ, Xu J. CAPTURE: In Situ Analysis of Chromatin Composition of Endogenous Genomic Loci by Biotinylated dCas9. ACTA ACUST UNITED AC 2018; 123:e64. [PMID: 29927077 DOI: 10.1002/cpmb.64] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cis-regulatory elements (CREs) play a pivotal role in spatiotemporal control of tissue-specific gene expression, yet the molecular composition of the vast majority of CREs in native chromatin remains unknown. In this article, we describe the clustered regularly interspaced short palindromic repeats (CRISPR) affinity purification in situ of regulatory elements (CAPTURE) approach to simultaneously identify locus-specific chromatin-regulating protein complexes and long-range DNA interactions. Using an in vivo biotinylated nuclease-deficient Cas9 (dCas9) protein and programmable single guide RNAs (sgRNAs), this approach allows for high-resolution and locus-specific isolation of protein complexes and long-range chromatin looping associated with single copy CREs in mammalian cells. Unbiased analysis of the compositional structure of developmentally regulated or disease-associated CREs identifies new features of transcriptional regulation. Hence, CAPTURE provides a versatile platform to study genomic locus-regulating chromatin composition in a mammalian genome. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Xin Liu
- Children's Medical Center Research Institute, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Yuannyu Zhang
- Children's Medical Center Research Institute, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Yong Chen
- Department of Biological Sciences, Center for Systems Biology, University of Texas at Dallas, Richardson, Texas
| | - Mushan Li
- Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zhen Shao
- Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Michael Q Zhang
- Department of Biological Sciences, Center for Systems Biology, University of Texas at Dallas, Richardson, Texas
| | - Jian Xu
- Children's Medical Center Research Institute, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
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16
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Wang P, Byrum S, Fowler FC, Pal S, Tackett AJ, Tyler JK. Proteomic identification of histone post-translational modifications and proteins enriched at a DNA double-strand break. Nucleic Acids Res 2017; 45:10923-10940. [PMID: 29036368 PMCID: PMC5737490 DOI: 10.1093/nar/gkx844] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 09/13/2017] [Indexed: 11/13/2022] Open
Abstract
Here, we use ChAP-MS (chromatin affinity purification with mass spectrometry), for the affinity purification of a sequence-specific single-copy endogenous chromosomal locus containing a DNA double-strand break (DSB). We found multiple new histone post-translational modifications enriched on chromatin bearing a DSB from budding yeast. One of these, methylation of histone H3 on lysine 125, has not previously been reported. Among over 100 novel proteins enriched at a DSB were the phosphatase Sit4, the RNA pol II degradation factor Def1, the mRNA export protein Yra1 and the HECT E3 ligase Tom1. Each of these proteins was required for resistance to radiomimetics, and many were required for resistance to heat, which we show here to cause a defect in DSB repair in yeast. Yra1 and Def1 were required for DSB repair per se, while Sit4 was required for rapid inactivation of the DNA damage checkpoint after DSB repair. Thus, our unbiased proteomics approach has led to the unexpected discovery of novel roles for these and other proteins in the DNA damage response.
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Affiliation(s)
- Pingping Wang
- Weill Cornell Medicine, Department of Pathology and Laboratory Medicine, New York, NY 10065, USA.,Genes and Development Graduate Program of the University of Texas MD Anderson Cancer Center, UT Health Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Stephanie Byrum
- University of Arkansas for Medical Sciences, Department of Biochemistry and Molecular Biology, Little Rock, AR 72205, USA
| | - Faith C Fowler
- Weill Cornell Medicine, Department of Pathology and Laboratory Medicine, New York, NY 10065, USA
| | - Sangita Pal
- Weill Cornell Medicine, Department of Pathology and Laboratory Medicine, New York, NY 10065, USA.,Genes and Development Graduate Program of the University of Texas MD Anderson Cancer Center, UT Health Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Alan J Tackett
- University of Arkansas for Medical Sciences, Department of Biochemistry and Molecular Biology, Little Rock, AR 72205, USA
| | - Jessica K Tyler
- Weill Cornell Medicine, Department of Pathology and Laboratory Medicine, New York, NY 10065, USA
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17
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Fujita T, Kitaura F, Yuno M, Suzuki Y, Sugano S, Fujii H. Locus-specific ChIP combined with NGS analysis reveals genomic regulatory regions that physically interact with the Pax5 promoter in a chicken B cell line. DNA Res 2017; 24:537-548. [PMID: 28586432 PMCID: PMC5737561 DOI: 10.1093/dnares/dsx023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 05/04/2017] [Indexed: 12/05/2022] Open
Abstract
Chromosomal interactions regulate genome functions, such as transcription, via dynamic chromosomal organization in the nucleus. In this study, we attempted to identify genomic regions that physically bind to the promoter region of the Pax5 gene, which encodes a master regulator for B cell lineage commitment, in a chicken B cell line, DT40, with the goal of obtaining mechanistic insight into transcriptional regulation through chromosomal interaction. We found that the Pax5 promoter bound to multiple genomic regions using locus-specific chromatin immunoprecipitation (locus-specific ChIP), a method for locus-specific isolation of target genomic regions, in combination with next-generation sequencing (NGS). Comparing chromosomal interactions in wild-type DT40 with those in a macrophage-like counterpart, we found that some of the identified chromosomal interactions were organized in a B cell-specific manner. In addition, deletion of a B cell-specific interacting genomic region in chromosome 11, which was marked by active enhancer histone modifications, resulted in moderate but significant down-regulation of Pax5 transcription. Together, these results suggested that Pax5 transcription in DT40 is regulated by B cell-specific inter-chromosomal interactions. Moreover, these analyses showed that locus-specific ChIP combined with NGS analysis is useful for non-biased identification of functional genomic regions that physically interact with a locus of interest.
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Affiliation(s)
- Toshitsugu Fujita
- Department of Biochemistry and Genome Biology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan.,Chromatin Biochemistry Research Group, Combined Program on Microbiology and Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Fusako Kitaura
- Chromatin Biochemistry Research Group, Combined Program on Microbiology and Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Miyuki Yuno
- Chromatin Biochemistry Research Group, Combined Program on Microbiology and Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yutaka Suzuki
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan.,Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Sumio Sugano
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan.,Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Hodaka Fujii
- Department of Biochemistry and Genome Biology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan.,Chromatin Biochemistry Research Group, Combined Program on Microbiology and Immunology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
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18
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Wierer M, Mann M. Proteomics to study DNA-bound and chromatin-associated gene regulatory complexes. Hum Mol Genet 2016; 25:R106-R114. [PMID: 27402878 PMCID: PMC5036873 DOI: 10.1093/hmg/ddw208] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 06/24/2016] [Indexed: 01/30/2023] Open
Abstract
High-resolution mass spectrometry (MS)-based proteomics is a powerful method for the identification of soluble protein complexes and large-scale affinity purification screens can decode entire protein interaction networks. In contrast, protein complexes residing on chromatin have been much more challenging, because they are difficult to purify and often of very low abundance. However, this is changing due to recent methodological and technological advances in proteomics. Proteins interacting with chromatin marks can directly be identified by pulldowns with synthesized histone tails containing posttranslational modifications (PTMs). Similarly, pulldowns with DNA baits harbouring single nucleotide polymorphisms or DNA modifications reveal the impact of those DNA alterations on the recruitment of transcription factors. Accurate quantitation – either isotope-based or label free – unambiguously pinpoints proteins that are significantly enriched over control pulldowns. In addition, protocols that combine classical chromatin immunoprecipitation (ChIP) methods with mass spectrometry (ChIP-MS) target gene regulatory complexes in their in-vivo context. Similar to classical ChIP, cells are crosslinked with formaldehyde and chromatin sheared by sonication or nuclease digested. ChIP-MS baits can be proteins in tagged or endogenous form, histone PTMs, or lncRNAs. Locus-specific ChIP-MS methods would allow direct purification of a single genomic locus and the proteins associated with it. There, loci can be targeted either by artificial DNA-binding sites and corresponding binding proteins or via proteins with sequence specificity such as TAL or nuclease deficient Cas9 in combination with a specific guide RNA. We predict that advances in MS technology will soon make such approaches generally applicable tools in epigenetics.
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Affiliation(s)
- Michael Wierer
- Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, Martinsried, Germany
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, Martinsried, Germany
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19
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Byrd AK, Zybailov BL, Maddukuri L, Gao J, Marecki JC, Jaiswal M, Bell MR, Griffin WC, Reed MR, Chib S, Mackintosh SG, MacNicol AM, Baldini G, Eoff RL, Raney KD. Evidence That G-quadruplex DNA Accumulates in the Cytoplasm and Participates in Stress Granule Assembly in Response to Oxidative Stress. J Biol Chem 2016; 291:18041-57. [PMID: 27369081 DOI: 10.1074/jbc.m116.718478] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Indexed: 12/13/2022] Open
Abstract
Cells engage numerous signaling pathways in response to oxidative stress that together repair macromolecular damage or direct the cell toward apoptosis. As a result of DNA damage, mitochondrial DNA or nuclear DNA has been shown to enter the cytoplasm where it binds to "DNA sensors," which in turn initiate signaling cascades. Here we report data that support a novel signaling pathway in response to oxidative stress mediated by specific guanine-rich sequences that can fold into G-quadruplex DNA (G4DNA). In response to oxidative stress, we demonstrate that sequences capable of forming G4DNA appear at increasing levels in the cytoplasm and participate in assembly of stress granules. Identified proteins that bind to endogenous G4DNA in the cytoplasm are known to modulate mRNA translation and participate in stress granule formation. Consistent with these findings, stress granule formation is known to regulate mRNA translation during oxidative stress. We propose a signaling pathway whereby cells can rapidly respond to DNA damage caused by oxidative stress. Guanine-rich sequences that are excised from damaged genomic DNA are proposed to enter the cytoplasm where they can regulate translation through stress granule formation. This newly proposed role for G4DNA provides an additional molecular explanation for why such sequences are prevalent in the human genome.
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Affiliation(s)
- Alicia K Byrd
- From the Departments of Biochemistry and Molecular Biology and
| | - Boris L Zybailov
- From the Departments of Biochemistry and Molecular Biology and the University of Arkansas at Little Rock/University of Arkansas for Medical Sciences (UALR/UAMS) Joint Graduate Program in Bioinformatics, University of Arkansas at Little Rock, Little Rock, Arkansas 72204
| | - Leena Maddukuri
- From the Departments of Biochemistry and Molecular Biology and
| | - Jun Gao
- From the Departments of Biochemistry and Molecular Biology and
| | - John C Marecki
- From the Departments of Biochemistry and Molecular Biology and
| | - Mihir Jaiswal
- the University of Arkansas at Little Rock/University of Arkansas for Medical Sciences (UALR/UAMS) Joint Graduate Program in Bioinformatics, University of Arkansas at Little Rock, Little Rock, Arkansas 72204
| | - Matthew R Bell
- From the Departments of Biochemistry and Molecular Biology and
| | | | - Megan R Reed
- From the Departments of Biochemistry and Molecular Biology and
| | - Shubeena Chib
- From the Departments of Biochemistry and Molecular Biology and
| | - Samuel G Mackintosh
- From the Departments of Biochemistry and Molecular Biology and the Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and
| | - Angus M MacNicol
- the Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and Neurobiology and Developmental Sciences and
| | - Giulia Baldini
- From the Departments of Biochemistry and Molecular Biology and
| | - Robert L Eoff
- From the Departments of Biochemistry and Molecular Biology and the Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and
| | - Kevin D Raney
- From the Departments of Biochemistry and Molecular Biology and the Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205 and
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20
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Guillen-Ahlers H, Rao PK, Levenstein ME, Kennedy-Darling J, Perumalla DS, Jadhav AYL, Glenn JP, Ludwig-Kubinski A, Drigalenko E, Montoya MJ, Göring HH, Anderson CD, Scalf M, Gildersleeve HIS, Cole R, Greene AM, Oduro AK, Lazarova K, Cesnik AJ, Barfknecht J, Cirillo LA, Gasch AP, Shortreed MR, Smith LM, Olivier M. HyCCAPP as a tool to characterize promoter DNA-protein interactions in Saccharomyces cerevisiae. Genomics 2016; 107:267-73. [PMID: 27184763 DOI: 10.1016/j.ygeno.2016.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 05/11/2016] [Accepted: 05/12/2016] [Indexed: 11/30/2022]
Abstract
Currently available methods for interrogating DNA-protein interactions at individual genomic loci have significant limitations, and make it difficult to work with unmodified cells or examine single-copy regions without specific antibodies. In this study, we describe a physiological application of the Hybridization Capture of Chromatin-Associated Proteins for Proteomics (HyCCAPP) methodology we have developed. Both novel and known locus-specific DNA-protein interactions were identified at the ENO2 and GAL1 promoter regions of Saccharomyces cerevisiae, and revealed subgroups of proteins present in significantly different levels at the loci in cells grown on glucose versus galactose as the carbon source. Results were validated using chromatin immunoprecipitation. Overall, our analysis demonstrates that HyCCAPP is an effective and flexible technology that does not require specific antibodies nor prior knowledge of locally occurring DNA-protein interactions and can now be used to identify changes in protein interactions at target regions in the genome in response to physiological challenges.
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Affiliation(s)
- Hector Guillen-Ahlers
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Prahlad K Rao
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Mark E Levenstein
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | | | - Danu S Perumalla
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Avinash Y L Jadhav
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Jeremy P Glenn
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Amy Ludwig-Kubinski
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Eugene Drigalenko
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Maria J Montoya
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Harald H Göring
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA
| | - Corianna D Anderson
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Mark Scalf
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | | | - Regina Cole
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Alexandra M Greene
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Akua K Oduro
- Department of Cell Biology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Katarina Lazarova
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Anthony J Cesnik
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Jared Barfknecht
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Lisa A Cirillo
- Department of Cell Biology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Audrey P Gasch
- Department of Genetics, University of Wisconsin, Madison, WI 53706, USA
| | | | - Lloyd M Smith
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Michael Olivier
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX 78227, USA; Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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21
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Wu TP, Wang T, Seetin MG, Lai Y, Zhu S, Lin K, Liu Y, Byrum SD, Mackintosh SG, Zhong M, Tackett A, Wang G, Hon LS, Fang G, Swenberg JA, Xiao AZ. DNA methylation on N(6)-adenine in mammalian embryonic stem cells. Nature 2016; 532:329-33. [PMID: 27027282 DOI: 10.1038/nature17640] [Citation(s) in RCA: 431] [Impact Index Per Article: 53.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 03/07/2016] [Indexed: 12/29/2022]
Abstract
It has been widely accepted that 5-methylcytosine is the only form of DNA methylation in mammalian genomes. Here we identify N(6)-methyladenine as another form of DNA modification in mouse embryonic stem cells. Alkbh1 encodes a demethylase for N(6)-methyladenine. An increase of N(6)-methyladenine levels in Alkbh1-deficient cells leads to transcriptional silencing. N(6)-methyladenine deposition is inversely correlated with the evolutionary age of LINE-1 transposons; its deposition is strongly enriched at young (<1.5 million years old) but not old (>6 million years old) L1 elements. The deposition of N(6)-methyladenine correlates with epigenetic silencing of such LINE-1 transposons, together with their neighbouring enhancers and genes, thereby resisting the gene activation signals during embryonic stem cell differentiation. As young full-length LINE-1 transposons are strongly enriched on the X chromosome, genes located on the X chromosome are also silenced. Thus, N(6)-methyladenine developed a new role in epigenetic silencing in mammalian evolution distinct from its role in gene activation in other organisms. Our results demonstrate that N(6)-methyladenine constitutes a crucial component of the epigenetic regulation repertoire in mammalian genomes.
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Affiliation(s)
- Tao P Wu
- Department of Genetics and Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Tao Wang
- Department of Genetics and Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Matthew G Seetin
- Pacific Biosciences, 1380 Willow Road, Menlo Park, California 94025, USA
| | - Yongquan Lai
- Environmental Sciences &Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Shijia Zhu
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York 10029, USA
| | - Kaixuan Lin
- Department of Genetics and Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Yifei Liu
- Department of Genetics and Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Stephanie D Byrum
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
| | - Samuel G Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
| | - Mei Zhong
- Yale Stem Cell Center and Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Alan Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
| | - Guilin Wang
- Department of Molecular Biophysics &Biochemistry, Yale Center for Genome Analysis, Yale School of Medicine, New Haven, Connecticut 06520, USA
| | - Lawrence S Hon
- Pacific Biosciences, 1380 Willow Road, Menlo Park, California 94025, USA
| | - Gang Fang
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York 10029, USA
| | - James A Swenberg
- Environmental Sciences &Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Andrew Z Xiao
- Department of Genetics and Yale Stem Cell Center, Yale School of Medicine, New Haven, Connecticut 06520, USA
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22
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Abstract
Hundreds of distinct chemical modifications to DNA and histone amino acids have been described. Regulation exerted by these so-called epigenetic marks is vital to normal development, stability of cell identity through mitosis, and nongenetic transmission of traits between generations through meiosis. Loss of this regulation contributes to many diseases. Evidence indicates epigenetic marks function in combinations, whereby a given modification has distinct effects on local genome control, depending on which additional modifications are locally present. This review summarizes emerging methods for assessing combinatorial epigenomic states, as well as challenges and opportunities for their refinement.
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Affiliation(s)
- Paul D. Soloway
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, United States
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23
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Noberini R, Sigismondo G, Bonaldi T. The contribution of mass spectrometry-based proteomics to understanding epigenetics. Epigenomics 2016; 8:429-45. [DOI: 10.2217/epi.15.108] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Chromatin is a macromolecular complex composed of DNA and histones that regulate gene expression and nuclear architecture. The concerted action of DNA methylation, histone post-translational modifications and chromatin-associated proteins control the epigenetic regulation of the genome, ultimately determining cell fate and the transcriptional outputs of differentiated cells. Deregulation of this complex machinery leads to disease states, and exploiting epigenetic drugs is becoming increasingly attractive for therapeutic intervention. Mass spectrometry (MS)-based proteomics emerged as a powerful tool complementary to genomic approaches for epigenetic research, allowing the unbiased and comprehensive analysis of histone post-translational modifications and the characterization of chromatin constituents and chromatin-associated proteins. Furthermore, MS holds great promise for epigenetic biomarker discovery and represents a useful tool for deconvolution of epigenetic drug targets. Here, we will provide an overview of the applications of MS-based proteomics in various areas of chromatin biology.
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Affiliation(s)
- Roberta Noberini
- Center for Genomic Science of IIT@SEMM, Istituto Italiano di Tecnologia, via Adamello 16, Milano, Italy
| | - Gianluca Sigismondo
- Department of Experimental Oncology, European Institute of Oncology, via Adamello 16, Milano, Italy
| | - Tiziana Bonaldi
- Department of Experimental Oncology, European Institute of Oncology, via Adamello 16, Milano, Italy
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24
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Laufer BI, Singh SM. Strategies for precision modulation of gene expression by epigenome editing: an overview. Epigenetics Chromatin 2015; 8:34. [PMID: 26388942 PMCID: PMC4574080 DOI: 10.1186/s13072-015-0023-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 08/19/2015] [Indexed: 01/27/2023] Open
Abstract
Genome editing technology has evolved rather quickly and become accessible to most researchers. It has resulted in far reaching implications and a number of novel designer systems including epigenome editing. Epigenome editing utilizes a combination of nuclease-null genome editing systems and effector domains to modulate gene expression. In particular, Zinc Finger, Transcription-Activator-Like Effector, and CRISPR/Cas9 have emerged as modular systems that can be modified to allow for precision manipulation of epigenetic marks without altering underlying DNA sequence. This review contains a comprehensive catalog of effector domains that can be used with components of genome editing systems to achieve epigenome editing. Ultimately, the evidence-based design of epigenome editing offers a novel improvement to the limited attenuation strategies. There is much potential for editing and/or correcting gene expression in somatic cells toward a new era of functional genomics and personalized medicine.
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Affiliation(s)
- Benjamin I Laufer
- Molecular Genetics Unit, Department of Biology, University of Western Ontario, London, ON Canada
| | - Shiva M Singh
- Molecular Genetics Unit, Department of Biology, University of Western Ontario, London, ON Canada
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25
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Hoffman EA, Frey BL, Smith LM, Auble DT. Formaldehyde crosslinking: a tool for the study of chromatin complexes. J Biol Chem 2015; 290:26404-11. [PMID: 26354429 DOI: 10.1074/jbc.r115.651679] [Citation(s) in RCA: 241] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Formaldehyde has been used for decades to probe macromolecular structure and function and to trap complexes, cells, and tissues for further analysis. Formaldehyde crosslinking is routinely employed for detection and quantification of protein-DNA interactions, interactions between chromatin proteins, and interactions between distal segments of the chromatin fiber. Despite widespread use and a rich biochemical literature, important aspects of formaldehyde behavior in cells have not been well described. Here, we highlight features of formaldehyde chemistry relevant to its use in analyses of chromatin complexes, focusing on how its properties may influence studies of chromatin structure and function.
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Affiliation(s)
- Elizabeth A Hoffman
- From the Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, Virginia 22908 and
| | - Brian L Frey
- the Department of Chemistry and Genome Center of Wisconsin, University of Wisconsin, Madison, Wisconsin 53706
| | - Lloyd M Smith
- the Department of Chemistry and Genome Center of Wisconsin, University of Wisconsin, Madison, Wisconsin 53706
| | - David T Auble
- From the Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, Virginia 22908 and
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26
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Burdine LJ, Burdine MS, Moreland L, Fogel B, Orr LM, James J, Turnage RH, Tackett AJ. Proteomic Identification of DNA-PK Involvement within the RET Signaling Pathway. PLoS One 2015; 10:e0127943. [PMID: 26065416 PMCID: PMC4466258 DOI: 10.1371/journal.pone.0127943] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/20/2015] [Indexed: 01/07/2023] Open
Abstract
Constitutive activation of the Rearranged during Transfection (RET) proto-oncogene leads to the development of MEN2A medullary thyroid cancer (MTC). The relatively clear genotype/phenotype relationship seen with RET mutations and the development of MEN2A is unusual in the fact that a single gene activity can drive the progression towards metastatic disease. Despite knowing the oncogene responsible for MEN2A, MTC, like most tumors of neural crest origin, remains largely resistant to chemotherapy. Constitutive activation of RET in a SK-N-MC cell line model reduces cell sensitivity to chemotherapy. In an attempt to identify components of the machinery responsible for the observed RET induced chemoresistance, we performed a proteomic screen of histones and associated proteins in cells with a constitutively active RET signaling pathway. The proteomic approach identified DNA-PKcs, a DNA damage response protein, as a target of the RET signaling pathway. Active DNA-PKcs, which is phosphorylated at site serine 2056 and localized to chromatin, was elevated within our model. Treatment with the RET inhibitor RPI-1 significantly reduced s2056 phosphorylation in RET cells as well as in a human medullary thyroid cancer cell line. Additionally, inhibition of DNA-PKcs activity diminished the chemoresistance observed in both cell lines. Importantly, we show that activated DNA-PKcs is elevated in medullary thyroid tumor samples and that expression correlates with expression of RET in thyroid tumors. These results highlight one mechanism by which RET signaling likely primes cells for rapid response to DNA damage and suggests DNA-PKcs as an additional target in MTC.
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Affiliation(s)
- Lyle J. Burdine
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
- * E-mail:
| | - Marie Schluterman Burdine
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
| | - Linley Moreland
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
| | - Brad Fogel
- Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
| | - Lisa M. Orr
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
| | - Jennifer James
- Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
| | - Richard H. Turnage
- Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
| | - Alan J. Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
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27
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Rogers JM, Barrera LA, Reyon D, Sander JD, Kellis M, Joung JK, Bulyk ML. Context influences on TALE-DNA binding revealed by quantitative profiling. Nat Commun 2015; 6:7440. [PMID: 26067805 PMCID: PMC4467457 DOI: 10.1038/ncomms8440] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/08/2015] [Indexed: 12/13/2022] Open
Abstract
Transcription activator-like effector (TALE) proteins recognize DNA using a seemingly simple DNA-binding code, which makes them attractive for use in genome engineering technologies that require precise targeting. Although this code is used successfully to design TALEs to target specific sequences, off-target binding has been observed and is difficult to predict. Here we explore TALE-DNA interactions comprehensively by quantitatively assaying the DNA-binding specificities of 21 representative TALEs to ∼5,000-20,000 unique DNA sequences per protein using custom-designed protein-binding microarrays (PBMs). We find that protein context features exert significant influences on binding. Thus, the canonical recognition code does not fully capture the complexity of TALE-DNA binding. We used the PBM data to develop a computational model, Specificity Inference For TAL-Effector Design (SIFTED), to predict the DNA-binding specificity of any TALE. We provide SIFTED as a publicly available web tool that predicts potential genomic off-target sites for improved TALE design.
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Affiliation(s)
- Julia M Rogers
- 1] Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA [2] Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Luis A Barrera
- 1] Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA [2] Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts 02138, USA [3] Harvard-MIT Division of Health Sciences and Technology (HST), Harvard Medical School, Boston, Massachusetts 02115, USA [4] Computer Science and Artificial Intelligence Laboratory, MIT, Cambridge, Massachusetts 02139, USA
| | - Deepak Reyon
- 1] Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA [2] Center for Computational and Integrative Biology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA [3] Center for Cancer Research, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA [4] Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jeffry D Sander
- 1] Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA [2] Center for Computational and Integrative Biology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA [3] Center for Cancer Research, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA [4] Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Manolis Kellis
- Computer Science and Artificial Intelligence Laboratory, MIT, Cambridge, Massachusetts 02139, USA
| | - J Keith Joung
- 1] Molecular Pathology Unit, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA [2] Center for Computational and Integrative Biology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA [3] Center for Cancer Research, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA [4] Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Martha L Bulyk
- 1] Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA [2] Committee on Higher Degrees in Biophysics, Harvard University, Cambridge, Massachusetts 02138, USA [3] Harvard-MIT Division of Health Sciences and Technology (HST), Harvard Medical School, Boston, Massachusetts 02115, USA [4] Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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28
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Pannkuk EL, Risch TS, Savary BJ. Isolation and identification of an extracellular subtilisin-like serine protease secreted by the bat pathogen Pseudogymnoascus destructans. PLoS One 2015; 10:e0120508. [PMID: 25785714 PMCID: PMC4364704 DOI: 10.1371/journal.pone.0120508] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 01/23/2015] [Indexed: 12/13/2022] Open
Abstract
White nose syndrome (WNS) is a cutaneous fungal disease of bats. WNS is responsible for unprecedented mortalities in North American cave bat populations. There have been few descriptions of enzyme activities that may function in WNS host/pathogen interactions, while no study has isolated and described secreted proteases. To address the hypothesis that Pseudogymnoascus destructans secretes extracellular proteases that function in wing necrosis during WNS infection, the object of this study was to culture P. destructans on various media, then isolate and structurally identify those proteases accumulated stably in the culture medium. We found a single dominant protease activity on minimal nutrient broth enriched with protein substrates, which was strongly inhibited by phenylmethylsulfonyl fluoride. This P. destructans serine protease (PdSP1) was isolated by preparative isoelectric focusing and concanavalin A lectin affinity chromatography. PdSP1 showed a molecular weight 27,900 (estimated by SDS-PAGE), broad pH optimum 6-8, and temperature optimum 60°C. Structural characterization of PdSP1 by MALDI-TOF MS, Orbitrap MS/MS, and Edman amino-terminal peptide sequencing matched it directly to a hypothetical protein accession from the sequenced P. destructans genome that is further identified as a MEROPS family S8A subtilisin-like serine peptidase. Two additional isoforms, PdSP2 and PdSP3, were identified in the P. destructans genome with 90% and 53% homology, respectively. P. destructans S8A serine proteases showed closer sequence conservation to P. pannorum and plant pathogenic fungi than to human pathogenic dermatophytes. Peptide-specific polyclonal antibodies developed from the PdSP1 sequence detected the protein in western blots. These subtilisin-like serine proteases are candidates for further functional studies in WNS host-pathogen interaction.
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Affiliation(s)
- Evan L. Pannkuk
- Graduate Program of Environmental Science, Arkansas State University, Jonesboro, Arkansas, United States of America
- * E-mail: (BJS); (ELP)
| | - Thomas S. Risch
- Department of Biological Sciences, Arkansas State University, Jonesboro, Arkansas, United States of America
| | - Brett J. Savary
- Arkansas Biosciences Institute, Arkansas State University, Jonesboro, Arkansas, United States of America
- * E-mail: (BJS); (ELP)
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29
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Maze I, Shen L, Zhang B, Garcia BA, Shao N, Mitchell A, Sun H, Akbarian S, Allis CD, Nestler EJ. Analytical tools and current challenges in the modern era of neuroepigenomics. Nat Neurosci 2014; 17:1476-90. [PMID: 25349914 DOI: 10.1038/nn.3816] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 08/20/2014] [Indexed: 12/14/2022]
Abstract
Over the past decade, rapid advances in epigenomics research have extensively characterized critical roles for chromatin regulatory events during normal periods of eukaryotic cell development and plasticity, as well as part of aberrant processes implicated in human disease. Application of such approaches to studies of the CNS, however, is more recent. Here we provide a comprehensive overview of available tools for analyzing neuroepigenomics data, as well as a discussion of pending challenges specific to the field of neuroscience. Integration of numerous unbiased genome-wide and proteomic approaches will be necessary to fully understand the neuroepigenome and the extraordinarily complex nature of the human brain. This will be critical to the development of future diagnostic and therapeutic strategies aimed at alleviating the vast array of heterogeneous and genetically distinct disorders of the CNS.
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Affiliation(s)
- Ian Maze
- 1] Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York, USA. [2] Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Li Shen
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Bin Zhang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Benjamin A Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ningyi Shao
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Amanda Mitchell
- 1] Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA. [2] Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - HaoSheng Sun
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Schahram Akbarian
- 1] Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA. [2] Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - C David Allis
- Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, New York, USA
| | - Eric J Nestler
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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30
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Waldrip ZJ, Byrum SD, Storey AJ, Gao J, Byrd AK, Mackintosh SG, Wahls WP, Taverna SD, Raney KD, Tackett AJ. A CRISPR-based approach for proteomic analysis of a single genomic locus. Epigenetics 2014; 9:1207-11. [PMID: 25147920 PMCID: PMC4169012 DOI: 10.4161/epi.29919] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/24/2014] [Accepted: 07/12/2014] [Indexed: 01/23/2023] Open
Abstract
Any given chromosomal activity (e.g., transcription) is governed predominantly by the local epiproteome. However, defining local epiproteomes has been limited by a lack of effective technologies to isolate discrete sections of chromatin and to identify with precision specific proteins and histone posttranslational modifications (PTMs). We report the use of the Cas9 and guide RNA (gRNA) components of the CRISPR system for gRNA-directed purification of a discrete section of chromatin. Quantitative mass spectrometry provides for unambiguous identification of proteins and histone PTMs specifically associated with the enriched chromatin. This CRISPR-based Chromatin Affinity Purification with Mass Spectrometry (CRISPR-ChAP-MS) approach revealed changes in the local epiproteome of a promoter during activation of transcription. CRISPR-ChAP-MS thus has broad applications for discovering molecular components and dynamic regulation of any in vivo activity at a given chromosomal location.
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Affiliation(s)
- Zachary J Waldrip
- University of Arkansas for Medical Sciences; Department of Biochemistry and Molecular Biology; Little Rock, AR USA
| | - Stephanie D Byrum
- University of Arkansas for Medical Sciences; Department of Biochemistry and Molecular Biology; Little Rock, AR USA
| | - Aaron J Storey
- University of Arkansas for Medical Sciences; Department of Biochemistry and Molecular Biology; Little Rock, AR USA
| | - Jun Gao
- University of Arkansas for Medical Sciences; Department of Biochemistry and Molecular Biology; Little Rock, AR USA
| | - Alicia K Byrd
- University of Arkansas for Medical Sciences; Department of Biochemistry and Molecular Biology; Little Rock, AR USA
| | - Samuel G Mackintosh
- University of Arkansas for Medical Sciences; Department of Biochemistry and Molecular Biology; Little Rock, AR USA
| | - Wayne P Wahls
- University of Arkansas for Medical Sciences; Department of Biochemistry and Molecular Biology; Little Rock, AR USA
| | - Sean D Taverna
- Department of Pharmacology and Molecular Sciences; Johns Hopkins University School of Medicine; Baltimore, MD USA
| | - Kevin D Raney
- University of Arkansas for Medical Sciences; Department of Biochemistry and Molecular Biology; Little Rock, AR USA
| | - Alan J Tackett
- University of Arkansas for Medical Sciences; Department of Biochemistry and Molecular Biology; Little Rock, AR USA
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31
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Booher NJ, Bogdanove AJ. Tools for TAL effector design and target prediction. Methods 2014; 69:121-7. [PMID: 24981075 PMCID: PMC4175064 DOI: 10.1016/j.ymeth.2014.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 06/11/2014] [Accepted: 06/13/2014] [Indexed: 10/25/2022] Open
Abstract
TAL effectors are transcription factors injected into plant cells by pathogenic bacteria during infection. They find their specific DNA targets via a string of contiguous, structural repeats that individually recognize single nucleotides (with some degeneracy) by virtue of polymorphisms at residue 13. The number of repeats and sequence of the amino acids at position 13 determine the nucleotide sequence of the DNA target. Due to this modularity, TAL effectors are readily engineered and have been used alone or as molecular fusions for targeted gene activation, gene repression, chromatin modification, chromatin tagging, and most broadly, for genome editing as TAL effector nucleases (TALENs). Several moderate and high-throughput cloning methods are in place for assembling TAL effector-based genetic constructs. Targeting is complicated to an extent by a general requirement for thymine to precede the DNA target, a requirement of TALENs to bind paired opposing sites separated by a defined range of distances, differential contributions of different repeat types to overall affinity, and a polarity to mismatch tolerance. Several computational tools are available online to aid in design and the identification of candidate off-target binding sites, as well as assembly and implementation. These tools vary in their approaches, capabilities, and relative utility for different types of TAL effector applications. Accuracy of off-target prediction is not well characterized yet for any of the tools and will require a better understanding of the qualitative and quantitative variation in the nucleotide preferences of individual repeats.
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Affiliation(s)
- Nicholas J Booher
- Plant Pathology and Plant-Microbe Biology, 334 Plant Science, Cornell University, Ithaca, NY 14853, USA.
| | - Adam J Bogdanove
- Plant Pathology and Plant-Microbe Biology, 334 Plant Science, Cornell University, Ithaca, NY 14853, USA.
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32
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Papazyan R, Voronina E, Chapman JR, Luperchio TR, Gilbert TM, Meier E, Mackintosh SG, Shabanowitz J, Tackett AJ, Reddy KL, Coyne RS, Hunt DF, Liu Y, Taverna SD. Methylation of histone H3K23 blocks DNA damage in pericentric heterochromatin during meiosis. eLife 2014; 3:e02996. [PMID: 25161194 PMCID: PMC4141274 DOI: 10.7554/elife.02996] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Despite the well-established role of heterochromatin in protecting chromosomal integrity during meiosis and mitosis, the contribution and extent of heterochromatic histone posttranslational modifications (PTMs) remain poorly defined. Here, we gained novel functional insight about heterochromatic PTMs by analyzing histone H3 purified from the heterochromatic germline micronucleus of the model organism Tetrahymena thermophila. Mass spectrometric sequencing of micronuclear H3 identified H3K23 trimethylation (H3K23me3), a previously uncharacterized PTM. H3K23me3 became particularly enriched during meiotic leptotene and zygotene in germline chromatin of Tetrahymena and C. elegans. Loss of H3K23me3 in Tetrahymena through deletion of the methyltransferase Ezl3p caused mislocalization of meiosis-induced DNA double-strand breaks (DSBs) to heterochromatin, and a decrease in progeny viability. These results show that an evolutionarily conserved developmental pathway regulates H3K23me3 during meiosis, and our studies in Tetrahymena suggest this pathway may function to protect heterochromatin from DSBs. DOI:http://dx.doi.org/10.7554/eLife.02996.001 Inside the nucleus of a cell, the DNA is wound around histone proteins. This forms a structure called chromatin that allows the long DNA strands to fit inside the cell. Variations in chromatin structure also help the cell to control the functional properties of DNA. For example, a large proportion of chromatin in the cell is in the form of heterochromatin, which is very densely packed, and is associated with many roles such as gene silencing and keeping DNA intact during reproduction. Many animals and plants have two copies of each DNA molecule: one inherited from the mother, and one from the father of the organism. Reproductive cells undergo a process called recombination when they form, where the matching copies of each DNA molecule break in a number of places and rejoin to form a new ‘blend’ of their mother's and their father's DNA, which is passed on to their own offspring. In contrast, most heterochromatin is inherited without recombining, preserving it in an unaltered form. This is important since recombination in heterochromatin can create genetic abnormalities. Adding small chemical modifications—such as methyl groups—to the histone proteins at the core of the chromatin can change how the DNA is packed. However, the histone modifications that yield different chromatin structures, and the effect of these modifications, are not very well understood. Papazyan et al. have taken advantage of a distinct feature of the protozoan Tetrahymena thermophila: a single-celled organism that divides its chromatin into two different nuclei. The smaller micronuclei contain only heterochromatin, and Papazyan et al. discovered that the histone H3 protein in the micronuclei is modified by methyl groups at a specific site that had not been studied before. Furthermore, this protozoan makes more of these modifications when it reproduces. An enzyme called Ezl3p adds these methyl groups, and without this enzyme T. thermophila reproduces more slowly and has offspring that are less likely to survive and more likely to be infertile. Papazyan et al. provide evidence that these characteristics arise because the cells without the histone modification are unable to prevent DNA breaks from occurring in heterochromatin during recombination. The same histone modification also occurs when the microscopic worm Caenorhabditis elegans reproduces, suggesting that this method of DNA protection has been conserved throughout evolution. Papazyan et al. propose that the histone modification may prevent another enzyme that induces DNA breaks from accessing the heterochromatin in reproductive cells; but more work is required to support this hypothesis. These findings reveal the importance of a new histone modification during reproduction, and could provide new directions for infertility research. DOI:http://dx.doi.org/10.7554/eLife.02996.002
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Affiliation(s)
- Romeo Papazyan
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, United States Center for Epigenetics, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Ekaterina Voronina
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, The Johns Hopkins University School of Medicine, Balitmore, United States Center for Cell Dynamics, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Jessica R Chapman
- Department of Chemistry, University of Virginia, Charlottesville, United States
| | - Teresa R Luperchio
- Center for Epigenetics, The Johns Hopkins University School of Medicine, Baltimore, United States Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Tonya M Gilbert
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, United States Center for Epigenetics, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Elizabeth Meier
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, United States Center for Epigenetics, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Samuel G Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, United States
| | - Jeffrey Shabanowitz
- Department of Chemistry, University of Virginia, Charlottesville, United States
| | - Alan J Tackett
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, United States
| | - Karen L Reddy
- Center for Epigenetics, The Johns Hopkins University School of Medicine, Baltimore, United States Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, United States
| | - Robert S Coyne
- Department of Genomic Medicine, J. Craig Venter Institute, Rockville, United States
| | - Donald F Hunt
- Department of Chemistry, University of Virginia, Charlottesville, United States Department of Pathology, University of Virginia, Charlottesville, United States
| | - Yifan Liu
- Department of Pathology, University of Michigan Medical School, Ann Arbor, United States
| | - Sean D Taverna
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, United States Center for Epigenetics, The Johns Hopkins University School of Medicine, Baltimore, United States
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Müller-Ott K, Erdel F, Matveeva A, Mallm JP, Rademacher A, Hahn M, Bauer C, Zhang Q, Kaltofen S, Schotta G, Höfer T, Rippe K. Specificity, propagation, and memory of pericentric heterochromatin. Mol Syst Biol 2014; 10:746. [PMID: 25134515 PMCID: PMC4299515 DOI: 10.15252/msb.20145377] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The cell establishes heritable patterns of active and silenced chromatin via interacting factors
that set, remove, and read epigenetic marks. To understand how the underlying networks operate, we
have dissected transcriptional silencing in pericentric heterochromatin (PCH) of mouse fibroblasts.
We assembled a quantitative map for the abundance and interactions of 16 factors related to PCH in
living cells and found that stably bound complexes of the histone methyltransferase SUV39H1/2
demarcate the PCH state. From the experimental data, we developed a predictive mathematical model
that explains how chromatin-bound SUV39H1/2 complexes act as nucleation sites and propagate a
spatially confined PCH domain with elevated histone H3 lysine 9 trimethylation levels via chromatin
dynamics. This “nucleation and looping” mechanism is particularly robust toward
transient perturbations and stably maintains the PCH state. These features make it an attractive
model for establishing functional epigenetic domains throughout the genome based on the localized
immobilization of chromatin-modifying enzymes.
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Affiliation(s)
- Katharina Müller-Ott
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Research Group Genome Organization & Function, Heidelberg, Germany
| | - Fabian Erdel
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Research Group Genome Organization & Function, Heidelberg, Germany
| | - Anna Matveeva
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Division Theoretical Systems Biology, Heidelberg, Germany
| | - Jan-Philipp Mallm
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Research Group Genome Organization & Function, Heidelberg, Germany
| | - Anne Rademacher
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Research Group Genome Organization & Function, Heidelberg, Germany
| | - Matthias Hahn
- Munich Center for Integrated Protein Science and Adolf Butenandt Institute, Ludwig Maximilians University, Munich, Germany
| | - Caroline Bauer
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Research Group Genome Organization & Function, Heidelberg, Germany
| | - Qin Zhang
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Division Theoretical Systems Biology, Heidelberg, Germany
| | - Sabine Kaltofen
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Research Group Genome Organization & Function, Heidelberg, Germany
| | - Gunnar Schotta
- Munich Center for Integrated Protein Science and Adolf Butenandt Institute, Ludwig Maximilians University, Munich, Germany
| | - Thomas Höfer
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Division Theoretical Systems Biology, Heidelberg, Germany
| | - Karsten Rippe
- Deutsches Krebsforschungszentrum (DKFZ) and BioQuant, Research Group Genome Organization & Function, Heidelberg, Germany
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Cieniewicz AM, Moreland L, Ringel AE, Mackintosh SG, Raman A, Gilbert TM, Wolberger C, Tackett AJ, Taverna SD. The bromodomain of Gcn5 regulates site specificity of lysine acetylation on histone H3. Mol Cell Proteomics 2014; 13:2896-910. [PMID: 25106422 DOI: 10.1074/mcp.m114.038174] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
In yeast, the conserved histone acetyltransferase (HAT) Gcn5 associates with Ada2 and Ada3 to form the catalytic module of the ADA and SAGA transcriptional coactivator complexes. Gcn5 also contains an acetyl-lysine binding bromodomain that has been implicated in regulating nucleosomal acetylation in vitro, as well as at gene promoters in cells. However, the contribution of the Gcn5 bromodomain in regulating site specificity of HAT activity remains unclear. Here, we used a combined acid-urea gel and quantitative mass spectrometry approach to compare the HAT activity of wild-type and Gcn5 bromodomain-mutant ADA subcomplexes (Gcn5-Ada2-Ada3). Wild-type ADA subcomplex acetylated H3 lysines with the following specificity; H3K14 > H3K23 > H3K9 ≈ H3K18 > H3K27 > H3K36. However, when the Gcn5 bromodomain was defective in acetyl-lysine binding, the ADA subcomplex demonstrated altered site-specific acetylation on free and nucleosomal H3, with H3K18ac being the most severely diminished. H3K18ac was also severely diminished on H3K14R, but not H3K23R, substrates in wild-type HAT reactions, further suggesting that Gcn5-catalyzed acetylation of H3K14 and bromodomain binding to H3K14ac are important steps preceding H3K18ac. In sum, this work details a previously uncharacterized cross-talk between the Gcn5 bromodomain "reader" function and enzymatic HAT activity that might ultimately affect gene expression. Future studies of how mutations in bromodomains or other histone post-translational modification readers can affect chromatin-templated enzymatic activities will yield unprecedented insight into a potential "histone/epigenetic code." MS data are available via ProteomeXchange with identifier PXD001167.
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Affiliation(s)
- Anne M Cieniewicz
- From the ‡Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; §Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Linley Moreland
- ¶Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Alison E Ringel
- ‖Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; **Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Samuel G Mackintosh
- ¶Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205
| | - Ana Raman
- From the ‡Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; §Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Tonya M Gilbert
- From the ‡Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; §Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Cynthia Wolberger
- §Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; ‖Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; **Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Alan J Tackett
- ¶Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205;
| | - Sean D Taverna
- From the ‡Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; §Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
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35
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Gilbert TM, McDaniel SL, Byrum SD, Cades JA, Dancy BCR, Wade H, Tackett AJ, Strahl BD, Taverna SD. A PWWP domain-containing protein targets the NuA3 acetyltransferase complex via histone H3 lysine 36 trimethylation to coordinate transcriptional elongation at coding regions. Mol Cell Proteomics 2014; 13:2883-95. [PMID: 25104842 DOI: 10.1074/mcp.m114.038224] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Post-translational modifications of histones, such as acetylation and methylation, are differentially positioned in chromatin with respect to gene organization. For example, although histone H3 is often trimethylated on lysine 4 (H3K4me3) and acetylated on lysine 14 (H3K14ac) at active promoter regions, histone H3 lysine 36 trimethylation (H3K36me3) occurs throughout the open reading frames of transcriptionally active genes. The conserved yeast histone acetyltransferase complex, NuA3, specifically binds H3K4me3 through a plant homeodomain (PHD) finger in the Yng1 subunit, and subsequently catalyzes the acetylation of H3K14 through the histone acetyltransferase domain of Sas3, leading to transcription initiation at a subset of genes. We previously found that Ylr455w (Pdp3), an uncharacterized proline-tryptophan-tryptophan-proline (PWWP) domain-containing protein, copurifies with stable members of NuA3. Here, we employ mass-spectrometric analysis of affinity purified Pdp3, biophysical binding assays, and genetic analyses to classify NuA3 into two functionally distinct forms: NuA3a and NuA3b. Although NuA3a uses the PHD finger of Yng1 to interact with H3K4me3 at the 5'-end of open reading frames, NuA3b contains the unique member, Pdp3, which regulates an interaction between NuA3b and H3K36me3 at the transcribed regions of genes through its PWWP domain. We find that deletion of PDP3 decreases NuA3-directed transcription and results in growth defects when combined with transcription elongation mutants, suggesting NuA3b acts as a positive elongation factor. Finally, we determine that NuA3a, but not NuA3b, is synthetically lethal in combination with a deletion of the histone acetyltransferase GCN5, indicating NuA3b has a specialized role at coding regions that is independent of Gcn5 activity. Collectively, these studies define a new form of the NuA3 complex that associates with H3K36me3 to effect transcriptional elongation. MS data are available via ProteomeXchange with identifier PXD001156.
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Affiliation(s)
- Tonya M Gilbert
- From the ‡Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205; §Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205
| | - Stephen L McDaniel
- ¶Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Stephanie D Byrum
- ‖Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205
| | - Jessica A Cades
- From the ‡Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205
| | - Blair C R Dancy
- From the ‡Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205; §Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205
| | - Herschel Wade
- **Department of Biophysics and Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205
| | - Alan J Tackett
- ‖Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, 72205
| | - Brian D Strahl
- ¶Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599; ‡‡Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599
| | - Sean D Taverna
- From the ‡Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205; §Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, 21205;
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Yamanaka S, Siomi MC, Siomi H. piRNA clusters and open chromatin structure. Mob DNA 2014; 5:22. [PMID: 25126116 PMCID: PMC4131230 DOI: 10.1186/1759-8753-5-22] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 07/09/2014] [Indexed: 12/27/2022] Open
Abstract
Transposable elements (TEs) are major structural components of eukaryotic genomes; however, mobilization of TEs generally has negative effects on the host genome. To counteract this threat, host cells have evolved genetic and epigenetic mechanisms that keep TEs silenced. One such mechanism involves the Piwi-piRNA complex, which represses TEs in animal gonads either by cleaving TE transcripts in the cytoplasm or by directing specific chromatin modifications at TE loci in the nucleus. Most Piwi-interacting RNAs (piRNAs) are derived from genomic piRNA clusters. There has been remarkable progress in our understanding of the mechanisms underlying piRNA biogenesis. However, little is known about how a specific locus in the genome is converted into a piRNA-producing site. In this review, we will discuss a possible link between chromatin boundaries and piRNA cluster formation.
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Affiliation(s)
- Soichiro Yamanaka
- Department of Molecular Biology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
| | - Mikiko C Siomi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan
| | - Haruhiko Siomi
- Department of Molecular Biology, Keio University School of Medicine, 35 Shinanomachi Shinjuku-ku, Tokyo 160-8582, Japan
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37
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Kennedy-Darling J, Guillen-Ahlers H, Shortreed MR, Scalf M, Frey BL, Kendziorski C, Olivier M, Gasch AP, Smith LM. Discovery of Chromatin-Associated Proteins via Sequence-Specific Capture and Mass Spectrometric Protein Identification in Saccharomyces cerevisiae. J Proteome Res 2014; 13:3810-25. [PMID: 24999558 PMCID: PMC4123949 DOI: 10.1021/pr5004938] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
![]()
DNA–protein
interactions play critical roles in the control
of genome expression and other fundamental processes. An essential
element in understanding how these systems function is to identify
their molecular components. We present here a novel strategy, Hybridization
Capture of Chromatin Associated Proteins for Proteomics (HyCCAPP),
to identify proteins that are interacting with any given region of
the genome. This technology identifies and quantifies the proteins
that are specifically interacting with a genomic region of interest
by sequence-specific hybridization capture of the target region from in vivo cross-linked chromatin, followed by mass spectrometric
identification and quantification of associated proteins. We demonstrate
the utility of HyCCAPP by identifying proteins associated with three
multicopy and one single-copy loci in yeast. In each case, a locus-specific
pattern of target-associated proteins was revealed. The binding of
previously unknown proteins was confirmed by ChIP in 11 of 17 cases.
The identification of many previously known proteins at each locus
provides strong support for the ability of HyCCAPP to correctly identify
DNA-associated proteins in a sequence-specific manner, while the discovery
of previously unknown proteins provides new biological insights into
transcriptional and regulatory processes at the target locus.
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Affiliation(s)
| | - Hector Guillen-Ahlers
- ‡Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas 78227, United States
| | | | | | | | | | - Michael Olivier
- ‡Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas 78227, United States
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38
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Abstract
Xanthomonas phytopathogenic bacteria produce unique transcription activator-like effector (TALE) proteins that recognize and activate specific plant promoters through a set of tandem repeats. A unique TALE-DNA-binding code uses two polymorphic amino acids in each repeat to mediate recognition of specific nucleotides. The order of repeats determines effector’s specificity toward the cognate nucleotide sequence of the sense DNA strand. Artificially designed TALE-DNA-binding domains fused to nuclease or activation and repressor domains provide an outstanding toolbox for targeted gene editing and gene regulation in research, biotechnology and gene therapy. Gene editing with custom-designed TALE nucleases (TALENs) extends the repertoire of targeted genome modifications across a broad spectrum of organisms ranging from plants and insect to mammals.
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39
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Bogdanove AJ. Principles and applications of TAL effectors for plant physiology and metabolism. CURRENT OPINION IN PLANT BIOLOGY 2014; 19:99-104. [PMID: 24907530 PMCID: PMC4086460 DOI: 10.1016/j.pbi.2014.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 05/08/2014] [Accepted: 05/08/2014] [Indexed: 05/27/2023]
Abstract
Recent advances in DNA targeting allow unprecedented control over gene function and expression. Targeting based on TAL effectors is arguably the most promising for systems biology and metabolic engineering. Multiple, orthogonal TAL-effector reagents of different types can be used in the same cell. Furthermore, variation in base preferences of the individual structural repeats that make up the TAL effector DNA recognition domain makes targeting stringency tunable. Realized applications range from genome editing to epigenome modification to targeted gene regulation to chromatin labeling and capture. The principles that govern TAL effector DNA recognition make TAL effectors well suited for applications relevant to plant physiology and metabolism. TAL effector targeting has merits that are distinct from those of the RNA-based DNA targeting CRISPR/Cas9 system.
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Affiliation(s)
- Adam J Bogdanove
- Plant Pathology and Plant-Microbe Biology, 334 Plant Science, Cornell University, Ithaca, NY 14853, USA.
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40
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Guillen-Ahlers H, Shortreed MR, Smith LM, Olivier M. Advanced methods for the analysis of chromatin-associated proteins. Physiol Genomics 2014; 46:441-7. [PMID: 24803678 DOI: 10.1152/physiolgenomics.00041.2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
DNA-protein interactions are central to gene expression and chromatin regulation and have become one of the main focus areas of the ENCODE consortium. Advances in mass spectrometry and associated technologies have facilitated studies of these interactions, revealing many novel DNA-interacting proteins and histone posttranslational modifications. Proteins interacting at a single locus or at multiple loci have been targeted in these recent studies, each requiring a separate analytical strategy for isolation and analysis of DNA-protein interactions. The enrichment of target chromatin fractions occurs via a number of methods including immunoprecipitation, affinity purification, and hybridization, with the shared goal of using proteomics approaches as the final readout. The result of this is a number of exciting new tools, with distinct strengths and limitations that can enable highly robust and novel chromatin studies when applied appropriately. The present review compares and contrasts these methods to help the reader distinguish the advantages of each approach.
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Affiliation(s)
- Hector Guillen-Ahlers
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas; and
| | | | - Lloyd M Smith
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin
| | - Michael Olivier
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas; and
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41
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Soldi M, Bremang M, Bonaldi T. Biochemical systems approaches for the analysis of histone modification readout. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:657-68. [PMID: 24681439 DOI: 10.1016/j.bbagrm.2014.03.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/06/2014] [Accepted: 03/18/2014] [Indexed: 11/28/2022]
Abstract
Chromatin is the macromolecular nucleoprotein complex that governs the organization of genetic material in the nucleus of eukaryotic cells. In chromatin, DNA is packed with histone proteins into nucleosomes. Core histones are prototypes of hyper-modified proteins, being decorated by a large number of site-specific reversible and irreversible post-translational modifications (PTMs), which contribute to the maintenance and modulation of chromatin plasticity, gene activation, and a variety of other biological processes and disease states. The observations of the variety, frequency and co-occurrence of histone modifications in distinct patterns at specific genomic loci have led to the idea that hPTMs can create a molecular barcode, read by effector proteins that translate it into a specific transcriptional state, or process, on the underlying DNA. However, despite the fact that this histone-code hypothesis was proposed more than 10 years ago, the molecular details of its working mechanisms are only partially characterized. In particular, two questions deserve specific investigation: how the different modifications associate and synergize into patterns and how these PTM configurations are read and translated by multi-protein complexes into a specific functional outcome on the genome. Mass spectrometry (MS) has emerged as a versatile tool to investigate chromatin biology, useful for both identifying and validating hPTMs, and to dissect the molecular determinants of histone modification readout systems. We review here the MS techniques and the proteomics methods that have been developed to address these fundamental questions in epigenetics research, emphasizing approaches based on the proteomic dissection of distinct native chromatin regions, with a critical evaluation of their present challenges and future potential. This article is part of a Special Issue entitled: Molecular mechanisms of histone modification function.
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Affiliation(s)
- Monica Soldi
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Michael Bremang
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Tiziana Bonaldi
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy.
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42
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Rothbart SB, Strahl BD. Interpreting the language of histone and DNA modifications. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:627-43. [PMID: 24631868 DOI: 10.1016/j.bbagrm.2014.03.001] [Citation(s) in RCA: 471] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/14/2014] [Accepted: 03/04/2014] [Indexed: 01/10/2023]
Abstract
A major mechanism regulating the accessibility and function of eukaryotic genomes are the covalent modifications to DNA and histone proteins that dependably package our genetic information inside the nucleus of every cell. Formally postulated over a decade ago, it is becoming increasingly clear that post-translational modifications (PTMs) on histones act singly and in combination to form a language or 'code' that is read by specialized proteins to facilitate downstream functions in chromatin. Underappreciated at the time was the level of complexity harbored both within histone PTMs and their combinations, as well as within the proteins that read and interpret the language. In addition to histone PTMs, newly-identified DNA modifications that can recruit specific effector proteins have raised further awareness that histone PTMs operate within a broader language of epigenetic modifications to orchestrate the dynamic functions associated with chromatin. Here, we highlight key recent advances in our understanding of the epigenetic language encompassing histone and DNA modifications and foreshadow challenges that lie ahead as we continue our quest to decipher the fundamental mechanisms of chromatin regulation. This article is part of a Special Issue entitled: Molecular mechanisms of histone modification function.
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Affiliation(s)
- Scott B Rothbart
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Brian D Strahl
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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43
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A TAL effector repeat architecture for frameshift binding. Nat Commun 2014; 5:3447. [PMID: 24614980 DOI: 10.1038/ncomms4447] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 02/13/2014] [Indexed: 11/08/2022] Open
Abstract
Transcription activator-like effectors (TALEs) are important Xanthomonas virulence factors that bind DNA via a unique tandem 34-amino-acid repeat domain to induce expression of plant genes. So far, TALE repeats are described to bind as a consecutive array to a consecutive DNA sequence, in which each repeat independently recognizes a single DNA base. This modular protein architecture enables the design of any desired DNA-binding specificity for biotechnology applications. Here we report that natural TALE repeats of unusual amino-acid sequence length break the strict one repeat-to-one base pair binding mode and introduce a local flexibility to TALE-DNA binding. This flexibility allows TALEs and TALE nucleases to recognize target sequence variants with single nucleotide deletions. The flexibility also allows TALEs to activate transcription at allelic promoters that otherwise confer resistance to the host plant.
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