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Kaplow IM, Banerjee A, Foo CS. Neural network modeling of differential binding between wild-type and mutant CTCF reveals putative binding preferences for zinc fingers 1-2. BMC Genomics 2022; 23:295. [PMID: 35410161 PMCID: PMC9004084 DOI: 10.1186/s12864-022-08486-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 03/21/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Many transcription factors (TFs), such as multi zinc-finger (ZF) TFs, have multiple DNA binding domains (DBDs), and deciphering the DNA binding motifs of individual DBDs is a major challenge. One example of such a TF is CCCTC-binding factor (CTCF), a TF with eleven ZFs that plays a variety of roles in transcriptional regulation, most notably anchoring DNA loops. Previous studies found that CTCF ZFs 3-7 bind CTCF's core motif and ZFs 9-11 bind a specific upstream motif, but the motifs of ZFs 1-2 have yet to be identified. RESULTS We developed a new approach to identifying the binding motifs of individual DBDs of a TF through analyzing chromatin immunoprecipitation sequencing (ChIP-seq) experiments in which a single DBD is mutated: we train a deep convolutional neural network to predict whether wild-type TF binding sites are preserved in the mutant TF dataset and interpret the model. We applied this approach to mouse CTCF ChIP-seq data and identified the known binding preferences of CTCF ZFs 3-11 as well as a putative GAG binding motif for ZF 1. We analyzed other CTCF datasets to provide additional evidence that ZF 1 is associated with binding at the motif we identified, and we found that the presence of the motif for ZF 1 is associated with CTCF ChIP-seq peak strength. CONCLUSIONS Our approach can be applied to any TF for which in vivo binding data from both the wild-type and mutated versions of the TF are available, and our findings provide new potential insights binding preferences of CTCF's DBDs.
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Affiliation(s)
- Irene M Kaplow
- Departments of Computer Science, Stanford University, 240 Pasteur Drive, Stanford, California, 94305, USA. .,Present address: Department of Computational Biology, Carnegie Mellon University, 5000 Forbes Avenue, Gates-Hillman Building Room 7703, Pittsburgh, PA, 15213, USA.
| | - Abhimanyu Banerjee
- Departments of Physics, Stanford University, 240 Pasteur Drive, Stanford, California, 94305, USA
| | - Chuan Sheng Foo
- Departments of Computer Science, Stanford University, 240 Pasteur Drive, Stanford, California, 94305, USA. .,Present address: Machine Intellection Department, Institute for Infocomm Research, 1 Fusionopolis Way, #21-01 Connexis South Tower, Singapore, 138632, Singapore.
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2
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Xiao T, Li X, Felsenfeld G. The Myc-associated zinc finger protein (MAZ) works together with CTCF to control cohesin positioning and genome organization. Proc Natl Acad Sci U S A 2021; 118:e2023127118. [PMID: 33558242 PMCID: PMC7896315 DOI: 10.1073/pnas.2023127118] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The Myc-associated zinc finger protein (MAZ) is often found at genomic binding sites adjacent to CTCF, a protein which affects large-scale genome organization through its interaction with cohesin. We show here that, like CTCF, MAZ physically interacts with a cohesin subunit and can arrest cohesin sliding independently of CTCF. It also shares with CTCF the ability to independently pause the elongating form of RNA polymerase II, and consequently affects RNA alternative splicing. CTCF/MAZ double sites are more effective at sequestering cohesin than sites occupied only by CTCF. Furthermore, depletion of CTCF results in preferential loss of CTCF from sites not occupied by MAZ. In an assay for insulation activity like that used for CTCF, binding of MAZ to sites between an enhancer and promoter results in down-regulation of reporter gene expression, supporting a role for MAZ as an insulator protein. Hi-C analysis of the effect of MAZ depletion on genome organization shows that local interactions within topologically associated domains (TADs) are disrupted, as well as contacts that establish the boundaries of individual TADs. We conclude that MAZ augments the action of CTCF in organizing the genome, but also shares properties with CTCF that allow it to act independently.
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Affiliation(s)
- Tiaojiang Xiao
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892-0540
| | - Xin Li
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892-0540
| | - Gary Felsenfeld
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892-0540
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3
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Cheng H, Zhang N, Pati D. Cohesin subunit RAD21: From biology to disease. Gene 2020; 758:144966. [PMID: 32687945 PMCID: PMC7949736 DOI: 10.1016/j.gene.2020.144966] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023]
Abstract
RAD21 (also known as KIAA0078, NXP1, HR21, Mcd1, Scc1, and hereafter called RAD21), an essential gene, encodes a DNA double-strand break (DSB) repair protein that is evolutionarily conserved in all eukaryotes from budding yeast to humans. RAD21 protein is a structural component of the highly conserved cohesin complex consisting of RAD21, SMC1a, SMC3, and SCC3 [STAG1 (SA1) and STAG2 (SA2) in metazoans] proteins, involved in sister chromatid cohesion. This function is essential for proper chromosome segregation, post-replicative DNA repair, and prevention of inappropriate recombination between repetitive regions. In interphase, cohesin also functions in the control of gene expression by binding to numerous sites within the genome. In addition to playing roles in the normal cell cycle and DNA DSB repair, RAD21 is also linked to the apoptotic pathways. Germline heterozygous or homozygous missense mutations in RAD21 have been associated with human genetic disorders, including developmental diseases such as Cornelia de Lange syndrome (CdLS) and chronic intestinal pseudo-obstruction (CIPO) called Mungan syndrome, respectively, and collectively termed as cohesinopathies. Somatic mutations and amplification of the RAD21 have also been widely reported in both human solid and hematopoietic tumors. Considering the role of RAD21 in a broad range of cellular processes that are hot spots in neoplasm, it is not surprising that the deregulation of RAD21 has been increasingly evident in human cancers. Herein, we review the biology of RAD21 and the cellular processes that this important protein regulates and discuss the significance of RAD21 deregulation in cancer and cohesinopathies.
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Affiliation(s)
- Haizi Cheng
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Nenggang Zhang
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States
| | - Debananda Pati
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, United States; Department of Pediatrics, Baylor College of Medicine, Houston, TX, United States; Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States.
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4
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Iwasaki Y, Ikemura T, Kurokawa K, Okada N. Implication of a new function of human tDNAs in chromatin organization. Sci Rep 2020; 10:17440. [PMID: 33060757 PMCID: PMC7567086 DOI: 10.1038/s41598-020-74499-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/14/2020] [Indexed: 02/03/2023] Open
Abstract
Transfer RNA genes (tDNAs) are essential genes that encode tRNAs in all species. To understand new functions of tDNAs, other than that of encoding tRNAs, we used ENCODE data to examine binding characteristics of transcription factors (TFs) for all tDNA regions (489 loci) in the human genome. We divided the tDNAs into three groups based on the number of TFs that bound to them. At the two extremes were tDNAs to which many TFs bound (Group 1) and those to which no TFs bound (Group 3). Several TFs involved in chromatin remodeling such as ATF3, EP300 and TBL1XR1 bound to almost all Group 1 tDNAs. Furthermore, almost all Group 1 tDNAs included DNase I hypersensitivity sites and may thus interact with other chromatin regions through their bound TFs, and they showed highly conserved synteny across tetrapods. In contrast, Group 3 tDNAs did not possess these characteristics. These data suggest the presence of a previously uncharacterized function of these tDNAs. We also examined binding of CTCF to tDNAs and their involvement in topologically associating domains (TADs) and lamina-associated domains (LADs), which suggest a new perspective on the evolution and function of tDNAs.
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Affiliation(s)
- Yuki Iwasaki
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
- Center for Information Biology, National Institute of Genetics, Mishima, Japan
| | - Toshimichi Ikemura
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Ken Kurokawa
- Center for Information Biology, National Institute of Genetics, Mishima, Japan
| | - Norihiro Okada
- Department of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan.
- School of Pharmacy, Kitasato University, Sagamihara, Kanagawa, Japan.
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5
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Zhang M, Zhao J, Lv Y, Wang W, Feng C, Zou W, Su L, Jiao J. Histone Variants and Histone Modifications in Neurogenesis. Trends Cell Biol 2020; 30:869-880. [PMID: 33011018 DOI: 10.1016/j.tcb.2020.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 09/02/2020] [Accepted: 09/07/2020] [Indexed: 12/20/2022]
Abstract
During embryonic brain development, neurogenesis requires the orchestration of gene expression to regulate neural stem cell (NSC) fate specification. Epigenetic regulation with specific emphasis on the modes of histone variants and histone post-translational modifications are involved in interactive gene regulation of central nervous system (CNS) development. Here, we provide a broad overview of the regulatory system of histone variants and histone modifications that have been linked to neurogenesis and diseases. We also review the crosstalk between different histone modifications and discuss how the 3D genome affects cell fate dynamics during brain development. Understanding the mechanisms of epigenetic regulation in neurogenesis has shifted the paradigm from single gene regulation to synergistic interactions to ensure healthy embryonic neurogenesis.
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Affiliation(s)
- Mengtian Zhang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; Innovation Academy for Stem Cell and Regeneration, Chinese Academy of Sciences, 100101 Beijing, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinyue Zhao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; Innovation Academy for Stem Cell and Regeneration, Chinese Academy of Sciences, 100101 Beijing, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuqing Lv
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; Innovation Academy for Stem Cell and Regeneration, Chinese Academy of Sciences, 100101 Beijing, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenwen Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; School of Life Sciences, University of Science and Technology of China, Hefei 230000, China
| | - Chao Feng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenzheng Zou
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; Innovation Academy for Stem Cell and Regeneration, Chinese Academy of Sciences, 100101 Beijing, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Libo Su
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; Innovation Academy for Stem Cell and Regeneration, Chinese Academy of Sciences, 100101 Beijing, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jianwei Jiao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; Innovation Academy for Stem Cell and Regeneration, Chinese Academy of Sciences, 100101 Beijing, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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6
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Patel M, Patel D, Datta S, Singh U. CGGBP1-regulated cytosine methylation at CTCF-binding motifs resists stochasticity. BMC Genet 2020; 21:84. [PMID: 32727353 PMCID: PMC7392725 DOI: 10.1186/s12863-020-00894-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 07/23/2020] [Indexed: 12/03/2022] Open
Abstract
Background The human CGGBP1 binds to GC-rich regions and interspersed repeats, maintains homeostasis of stochastic cytosine methylation and determines DNA-binding of CTCF. Interdependence between regulation of cytosine methylation and CTCF occupancy by CGGBP1 remains unknown. Results By analyzing methylated DNA-sequencing data obtained from CGGBP1-depleted cells, we report that some transcription factor-binding sites, including CTCF, resist stochastic changes in cytosine methylation. By analysing CTCF-binding sites we show that cytosine methylation changes at CTCF motifs caused by CGGBP1 depletion resist stochastic changes. These CTCF-binding sites are positioned at locations where the spread of cytosine methylation in cis depends on the levels of CGGBP1. Conclusion Our findings suggest that CTCF occupancy and functions are determined by CGGBP1-regulated cytosine methylation patterns.
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Affiliation(s)
- Manthan Patel
- HoMeCell Lab, Biological Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Divyesh Patel
- HoMeCell Lab, Biological Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Subhamoy Datta
- HoMeCell Lab, Biological Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, 382355, Gujarat, India
| | - Umashankar Singh
- HoMeCell Lab, Biological Engineering, Indian Institute of Technology Gandhinagar, Palaj, Gandhinagar, 382355, Gujarat, India.
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7
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Yang G, Ma A, Qin ZS, Chen L. Application of topic models to a compendium of ChIP-Seq datasets uncovers recurrent transcriptional regulatory modules. Bioinformatics 2020; 36:2352-2358. [PMID: 31899481 DOI: 10.1093/bioinformatics/btz975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/29/2019] [Accepted: 12/30/2019] [Indexed: 11/14/2022] Open
Abstract
MOTIVATION The availability of thousands of genome-wide coupling chromatin immunoprecipitation (ChIP)-Seq datasets across hundreds of transcription factors (TFs) and cell lines provides an unprecedented opportunity to jointly analyze large-scale TF-binding in vivo, making possible the discovery of the potential interaction and cooperation among different TFs. The interacted and cooperated TFs can potentially form a transcriptional regulatory module (TRM) (e.g. co-binding TFs), which helps decipher the combinatorial regulatory mechanisms. RESULTS We develop a computational method tfLDA to apply state-of-the-art topic models to multiple ChIP-Seq datasets to decipher the combinatorial binding events of multiple TFs. tfLDA is able to learn high-order combinatorial binding patterns of TFs from multiple ChIP-Seq profiles, interpret and visualize the combinatorial patterns. We apply the tfLDA to two cell lines with a rich collection of TFs and identify combinatorial binding patterns that show well-known TRMs and related TF co-binding events. AVAILABILITY AND IMPLEMENTATION A software R package tfLDA is freely available at https://github.com/lichen-lab/tfLDA. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Guodong Yang
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA.,Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, P. R. China
| | - Aiqun Ma
- Department of Cardiovascular Medicine, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, 710061, P. R. China
| | - Zhaohui S Qin
- Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Li Chen
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.,Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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8
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Freeman DM, Lou D, Li Y, Martos SN, Wang Z. The conserved DNMT1-dependent methylation regions in human cells are vulnerable to neurotoxicant rotenone exposure. Epigenetics Chromatin 2020; 13:17. [PMID: 32178731 PMCID: PMC7076959 DOI: 10.1186/s13072-020-00338-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 03/06/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Allele-specific DNA methylation (ASM) describes genomic loci that maintain CpG methylation at only one inherited allele rather than having coordinated methylation across both alleles. The most prominent of these regions are germline ASMs (gASMs) that control the expression of imprinted genes in a parent of origin-dependent manner and are associated with disease. However, our recent report reveals numerous ASMs at non-imprinted genes. These non-germline ASMs are dependent on DNA methyltransferase 1 (DNMT1) and strikingly show the feature of random, switchable monoallelic methylation patterns in the mouse genome. The significance of these ASMs to human health has not been explored. Due to their shared allelicity with gASMs, herein, we propose that non-traditional ASMs are sensitive to exposures in association with human disease. RESULTS We first explore their conservancy in the human genome. Our data show that our putative non-germline ASMs were in conserved regions of the human genome and located adjacent to genes vital for neuronal development and maturation. We next tested the hypothesized vulnerability of these regions by exposing human embryonic kidney cell HEK293 with the neurotoxicant rotenone for 24 h. Indeed,14 genes adjacent to our identified regions were differentially expressed from RNA-sequencing. We analyzed the base-resolution methylation patterns of the predicted non-germline ASMs at two neurological genes, HCN2 and NEFM, with potential to increase the risk of neurodegeneration. Both regions were significantly hypomethylated in response to rotenone. CONCLUSIONS Our data indicate that non-germline ASMs seem conserved between mouse and human genomes, overlap important regulatory factor binding motifs, and regulate the expression of genes vital to neuronal function. These results support the notion that ASMs are sensitive to environmental factors such as rotenone and may alter the risk of neurological disease later in life by disrupting neuronal development.
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Affiliation(s)
- Dana M Freeman
- Laboratory of Environmental Epigenomes, Department of Environmental Health & Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Dan Lou
- Laboratory of Environmental Epigenomes, Department of Environmental Health & Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Yanqiang Li
- Laboratory of Environmental Epigenomes, Department of Environmental Health & Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Suzanne N Martos
- Laboratory of Environmental Epigenomes, Department of Environmental Health & Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Zhibin Wang
- Laboratory of Environmental Epigenomes, Department of Environmental Health & Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
- The State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, 430062, Hubei, China.
- Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
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9
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Unraveling the Hierarchy of cis and trans Factors That Determine the DNA Binding by Peroxisome Proliferator-Activated Receptor γ. Mol Cell Biol 2020; 40:MCB.00547-19. [PMID: 31932484 DOI: 10.1128/mcb.00547-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 12/20/2019] [Indexed: 12/11/2022] Open
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear receptor essential for adipocyte development and the maintenance of the alternatively polarized macrophage phenotype. Biochemical studies have established that as an obligate heterodimer with retinoid X receptor (RXR), PPARγ binds directly repeated nuclear receptor half sites spaced by one nucleotide (direct repeat 1 [DR1]). However, it has not been analyzed systematically and genome-wide how cis factors such as the sequences of DR1s and adjacent sequences and trans factors such as cobinding lineage-determining transcription factors (LDTFs) contribute to the direct binding of PPARγ in different cellular contexts. We developed a novel motif optimization approach using sequence composition and chromatin immunoprecipitation with high-throughput sequencing (ChIP-seq) densities from macrophages and adipocytes to complement de novo motif enrichment analysis and to define and classify high-affinity binding sites. We found that approximately half of the PPARγ cistrome represents direct DNA binding; both half sites can be extended upstream, and these are typically not of equal strength within a DR1. Strategically positioned LDTFs have greater impact on PPARγ binding than the quality of DR1, and the presence of the extension of DR1 provides a remarkable synergy with LDTFs. This approach of considering not only nucleotide frequencies but also their contribution to protein binding in a cellular context is applicable to other transcription factors.
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10
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Wang XY, Zhang X, Wang TY, Jia YL, Xu DH, Yi DD. Shortened nuclear matrix attachment regions are sufficient for replication and maintenance of episomes in mammalian cells. Mol Biol Cell 2019; 30:2761-2770. [PMID: 31509492 PMCID: PMC6789156 DOI: 10.1091/mbc.e19-02-0108] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Matrix attachment regions (MARs) can mediate the replication of vector episomes in mammalian cells; however, the molecular mode of action remains unclear. Here, we assessed the characteristics of MARs and the mechanism that mediates episomal vector replication in mammalian cells. Five shortened subfragments of β-interferon MAR fragments were cloned and transferred into CHO cells, and transgene expression levels, presence of the gene, and the episomal maintenance mechanism were determined. Three shortened MAR derivatives (position 781–1320, 1201–1740, and 1621–2201) retained full MAR activity and mediated episomal vector replication. Moreover, the three shortened MARs showed higher transgene expression levels, greater efficiency in colony formation, and more persistent transgene expression compared with those of the original pEPI-1 plasmid, and three functional truncated MARs can bind to SAF-A MAR-binding protein. These results suggest that shortened MARs are sufficient for replication and maintenance of episomes in CHO cells.
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Affiliation(s)
- Xiao-Yin Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Xi Zhang
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Yan-Long Jia
- Pharmacy Collage, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Dan-Hua Xu
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Dan-Dan Yi
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang 453003, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, Henan, China
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11
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Pareek M, Almog Y, Bari VK, Hazkani-Covo E, Onn I, Covo S. Alternative Functional rad21 Paralogs in Fusarium oxysporum. Front Microbiol 2019; 10:1370. [PMID: 31275285 PMCID: PMC6591460 DOI: 10.3389/fmicb.2019.01370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 05/31/2019] [Indexed: 11/16/2022] Open
Abstract
Cohesin, the sister chromatid cohesion complex, is an essential complex that ensures faithful sister chromatid segregation in eukaryotes. It also participates in DNA repair, transcription and maintenance of chromosome structure. Mitotic cohesin is composed of Smc1, Smc3, Scc3, and Rad21/Mcd1. The meiotic cohesin complex contains Rec8, a Rad21 paralog and not Rad21 itself. Very little is known about sister chromatid cohesion in fungal plant pathogens. Fusarium oxysporum is an important fungal plant pathogen without known sexual life cycle. Here, we describe that F. oxysporum encodes for three Rad21 paralogs; Rad21, Rec8, and the first alternative Rad21 paralog in the phylum of ascomycete. This last paralog is found only in several fungal plant pathogens from the Fusarium family and thus termed rad21nc (non-conserved). Conserved rad21 (rad21c), rad21nc, and rec8 genes are expressed in F. oxysporum although the expression of rad21c is much higher than the other paralogs. F. oxysporum strains deleted for the rad21nc or rec8 genes were analyzed for their role in fungal life cycle. Δrad21nc and Δrec8 single mutants were proficient in sporulation, conidia germination, hyphal growth and pathogenicity under optimal growth conditions. Interestingly, Δrad21nc and Δrec8 single mutants germinate less effectively than wild type (WT) strains under DNA replication and mitosis stresses. We provide here the first genetic analysis of alternative rad21nc and rec8 paralogs in filamentous fungi. Our results suggest that rad21nc and rec8 may have a unique role in cell cycle related functions of F. oxysporum.
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Affiliation(s)
- Manish Pareek
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yael Almog
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Vinay Kumar Bari
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Einat Hazkani-Covo
- Department of Natural Sciences, Open University of Israel, Ra’anana, Israel
| | - Itay Onn
- The Azrieli Faculty of Medicine, Bar Ilan University, Safed, Israel
| | - Shay Covo
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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12
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The bipartite TAD organization of the X-inactivation center ensures opposing developmental regulation of Tsix and Xist. Nat Genet 2019; 51:1024-1034. [PMID: 31133748 PMCID: PMC6551226 DOI: 10.1038/s41588-019-0412-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 04/04/2019] [Indexed: 01/08/2023]
Abstract
The mouse X-inactivation center (Xic) locus represents a powerful model for understanding the links between genome architecture and gene regulation, with the non-coding genes Xist and Tsix showing opposite developmental expression patterns while being organized as an overlapping sense/antisense unit. The Xic is organized into two topologically associating domains (TADs) but the role of this architecture in orchestrating cis-regulatory information remains elusive. To explore this, we generated genomic inversions that swap the Xist/Tsix transcriptional unit and place their promoters in each other’s TAD. We found that this led to a switch in their expression dynamics: Xist became precociously and ectopically up-regulated, both in male and female pluripotent cells, while Tsix expression aberrantly persisted during differentiation. The topological partitioning of the Xic is thus critical to ensure proper developmental timing of X inactivation. Our study illustrates how the genomic architecture of cis-regulatory landscapes can affect the regulation of mammalian developmental processes.
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13
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Yu S, Zheng C, Zhou F, Baillie DL, Rose AM, Deng Z, Chu JSC. Genomic identification and functional analysis of essential genes in Caenorhabditis elegans. BMC Genomics 2018; 19:871. [PMID: 30514206 PMCID: PMC6278001 DOI: 10.1186/s12864-018-5251-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 11/14/2018] [Indexed: 11/27/2022] Open
Abstract
Background Essential genes are required for an organism’s viability and their functions can vary greatly, spreading across many pathways. Due to the importance of essential genes, large scale efforts have been undertaken to identify the complete set of essential genes and to understand their function. Studies of genome architecture and organization have found that genes are not randomly disturbed in the genome. Results Using combined genetic mapping, Illumina sequencing, and bioinformatics analyses, we successfully identified 44 essential genes with 130 lethal mutations in genomic regions of C. elegans of around 7.3 Mb from Chromosome I (left). Of the 44 essential genes, six of which were genes not characterized previously by mutant alleles, let-633/let-638 (B0261.1), let-128 (C53H9.2), let-511 (W09C3.4), let-162 (Y47G6A.18), let-510 (Y47G6A.19), and let-131 (Y71G12B.6). Examine essential genes with Hi-C data shows that essential genes tend to cluster within TAD units rather near TAD boundaries. We have also shown that essential genes in the left half of chromosome I in C. elegans function in enzyme and nucleic acid binding activities during fundamental processes, such as DNA replication, transcription, and translation. From protein-protein interaction networks, essential genes exhibit more protein connectivity than non-essential genes in the genome. Also, many of the essential genes show strong expression in embryos or early larvae stages, indicating that they are important to early development. Conclusions Our results confirmed that this work provided a more comprehensive picture of the essential gene and their functional characterization. These genetic resources will offer important tools for further heath and disease research. Electronic supplementary material The online version of this article (10.1186/s12864-018-5251-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shicheng Yu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, China. .,Wuhan Frasergen Bioinformatics, Wuhan East Lake High-tech Zone, Wuhan, 430075, China.
| | - Chaoran Zheng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, China
| | - Fan Zhou
- Wuhan Frasergen Bioinformatics, Wuhan East Lake High-tech Zone, Wuhan, 430075, China
| | - David L Baillie
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada
| | - Ann M Rose
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, Wuhan, 430071, China.
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Bakshi A, Bretz CL, Cain TL, Kim J. Intergenic and intronic DNA hypomethylated regions as putative regulators of imprinted domains. Epigenomics 2018; 10:445-461. [PMID: 29569934 DOI: 10.2217/epi-2017-0125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIM To investigate the regulatory potential of intergenic/intronic hypomethylated regions (iHMRs) within imprinted domains. MATERIALS & METHODS Based on the preliminary results of the histone modification and conservation profiles, we conducted reporter assays on the Peg3 and H19 domain iHMRs. The in vitro results were confirmed by the in vivo deletion of Peg3-iHMR designed to test its function in the Peg3 imprinted domain. RESULTS & CONCLUSION Initial bioinformatic analyses suggested that some iHMRs may be noncanonical enhancers for imprinted genes. Consistent with this, Peg3- and H19-iHMRs showed context-dependent promoter and enhancer activity. Further, deletion of Peg3-iHMR resulted in allele- and sex-specific misregulation of several imprinted genes within the domain. Taken together, these results suggest that some iHMRs may function as domain-wide regulators for the associated imprinted domains.
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Affiliation(s)
- Arundhati Bakshi
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Corey L Bretz
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Terri L Cain
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Joomyeong Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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15
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Rennie S, Dalby M, van Duin L, Andersson R. Transcriptional decomposition reveals active chromatin architectures and cell specific regulatory interactions. Nat Commun 2018; 9:487. [PMID: 29402885 PMCID: PMC5799294 DOI: 10.1038/s41467-017-02798-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 12/29/2017] [Indexed: 12/29/2022] Open
Abstract
Transcriptional regulation is tightly coupled with chromosomal positioning and three-dimensional chromatin architecture. However, it is unclear what proportion of transcriptional activity is reflecting such organisation, how much can be informed by RNA expression alone and how this impacts disease. Here, we develop a computational transcriptional decomposition approach separating the proportion of expression associated with genome organisation from independent effects not directly related to genomic positioning. We show that positionally attributable expression accounts for a considerable proportion of total levels and is highly informative of topological associating domain activities and organisation, revealing boundaries and chromatin compartments. Furthermore, expression data alone accurately predict individual enhancer-promoter interactions, drawing features from expression strength, stabilities, insulation and distance. We characterise predictions in 76 human cell types, observing extensive sharing of domains, yet highly cell-type-specific enhancer-promoter interactions and strong enrichments in relevant trait-associated variants. Overall, our work demonstrates a close relationship between transcription and chromatin architecture.
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Affiliation(s)
- Sarah Rennie
- The Bioinformatics Centre, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200, Copenhagen, Denmark
| | - Maria Dalby
- The Bioinformatics Centre, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200, Copenhagen, Denmark
| | - Lucas van Duin
- The Bioinformatics Centre, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200, Copenhagen, Denmark
| | - Robin Andersson
- The Bioinformatics Centre, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200, Copenhagen, Denmark.
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16
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Glinsky GV. Contribution of transposable elements and distal enhancers to evolution of human-specific features of interphase chromatin architecture in embryonic stem cells. Chromosome Res 2018; 26:61-84. [PMID: 29335803 DOI: 10.1007/s10577-018-9571-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/20/2017] [Accepted: 01/02/2018] [Indexed: 11/28/2022]
Abstract
Transposable elements have made major evolutionary impacts on creation of primate-specific and human-specific genomic regulatory loci and species-specific genomic regulatory networks (GRNs). Molecular and genetic definitions of human-specific changes to GRNs contributing to development of unique to human phenotypes remain a highly significant challenge. Genome-wide proximity placement analysis of diverse families of human-specific genomic regulatory loci (HSGRL) identified topologically associating domains (TADs) that are significantly enriched for HSGRL and designated rapidly evolving in human TADs. Here, the analysis of HSGRL, hESC-enriched enhancers, super-enhancers (SEs), and specific sub-TAD structures termed super-enhancer domains (SEDs) has been performed. In the hESC genome, 331 of 504 (66%) of SED-harboring TADs contain HSGRL and 68% of SEDs co-localize with HSGRL, suggesting that emergence of HSGRL may have rewired SED-associated GRNs within specific TADs by inserting novel and/or erasing existing non-coding regulatory sequences. Consequently, markedly distinct features of the principal regulatory structures of interphase chromatin evolved in the hESC genome compared to mouse: the SED quantity is 3-fold higher and the median SED size is significantly larger. Concomitantly, the overall TAD quantity is increased by 42% while the median TAD size is significantly decreased (p = 9.11E-37) in the hESC genome. Present analyses illustrate a putative global role for transposable elements and HSGRL in shaping the human-specific features of the interphase chromatin organization and functions, which are facilitated by accelerated creation of novel transcription factor binding sites and new enhancers driven by targeted placement of HSGRL at defined genomic coordinates. A trend toward the convergence of TAD and SED architectures of interphase chromatin in the hESC genome may reflect changes of 3D-folding patterns of linear chromatin fibers designed to enhance both regulatory complexity and functional precision of GRNs by creating predominantly a single gene (or a set of functionally linked genes) per regulatory domain structures. Collectively, present analyses reveal critical evolutionary contributions of transposable elements and distal enhancers to creation of thousands primate- and human-specific elements of a chromatin folding code, which defines the 3D context of interphase chromatin both restricting and facilitating biological functions of GRNs.
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Affiliation(s)
- Gennadi V Glinsky
- Institute of Engineering in Medicine, University of California, San Diego, 9500 Gilman Dr. MC 0435, La Jolla, CA, 92093-0435, USA.
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17
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Ruiz-Velasco M, Kumar M, Lai MC, Bhat P, Solis-Pinson AB, Reyes A, Kleinsorg S, Noh KM, Gibson TJ, Zaugg JB. CTCF-Mediated Chromatin Loops between Promoter and Gene Body Regulate Alternative Splicing across Individuals. Cell Syst 2017; 5:628-637.e6. [DOI: 10.1016/j.cels.2017.10.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 08/02/2017] [Accepted: 10/27/2017] [Indexed: 12/20/2022]
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18
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Blinka S, Rao S. Nanog Expression in Embryonic Stem Cells - An Ideal Model System to Dissect Enhancer Function. Bioessays 2017; 39:10.1002/bies.201700086. [PMID: 28977693 PMCID: PMC5878941 DOI: 10.1002/bies.201700086] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 08/31/2017] [Indexed: 01/17/2023]
Abstract
Embryonic stem cells (ESCs) are derived from the preimplantation embryo and can differentiate into virtually any other cell type (termed pluripotency), which is governed by lineage specific transcriptions factors (TFs) binding to cis regulatory elements (CREs) to mediate changes in gene expression. The reliance on transcriptional regulation to maintain pluripotency makes ESCs a valuable model to study the role of distal CREs such as enhancers in modulating gene expression to affect cell fate decisions. This review will highlight recent advance on transcriptional enhancers, focusing on studies performed in ESCs. In addition, we argue that the Nanog locus, which encodes for an ESC-critical TF, is particularly informative because it contains multiple co-regulated genes and enhancers in close proximity to one another. The unique landscape at Nanog permits the study of ongoing questions including whether multiple enhancers function additively versus synergistically, determinants of gene specificity, and cell-to-cell variability in gene expression.
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Affiliation(s)
- Steven Blinka
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Blood Research Institute, Blood Center of Wisconsin, 8733 West Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Sridhar Rao
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Blood Research Institute, Blood Center of Wisconsin, 8733 West Watertown Plank Road, Milwaukee, WI 53226, USA
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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19
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Lin X, Su J, Chen K, Rodriguez B, Li W. Sparse conserved under-methylated CpGs are associated with high-order chromatin structure. Genome Biol 2017; 18:163. [PMID: 28859663 PMCID: PMC5580327 DOI: 10.1186/s13059-017-1296-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 08/09/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Whole-genome bisulfite sequencing (WGBS) is the gold standard for studying landscape DNA methylation. Current computational methods for WGBS are mainly designed for gene regulatory regions with multiple under-methylated CpGs (UMCs), such as promoters and enhancers. RESULTS To reliably predict the functional importance of single isolated UMCs across the genome, which is usually not achievable using traditional methods, we develop a multi-sample-based method. We identified 9421 sparse conserved under-methylated CpGs (scUMCs) from 31 high-quality methylomes, which are enriched in distal interacting anchor regions co-occupied by multiple chromatin-loop factors and are flanked by highly methylated CpGs. Moreover, cell lineage-specific scUMCs are associated with essential developmental genes, regulators of cell differentiation, and chromatin remodeling enzymes. Dynamic methylation levels of scUMCs correlate with the intensity of chromatin interactions and binding of looping factors as well as patterns of gene expression. CONCLUSIONS We introduce an innovative computational method for the identification of scUMCs, which are novel epigenetic features associated with high-order chromatin structure, opening new directions in the study of the inter-relationships between DNA methylation and chromatin structure.
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Affiliation(s)
- Xueqiu Lin
- Division of Biostatistics, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030 USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030 USA
- Department of Bioinformatics, School of Life sciences and Technology, Tongji University, Shanghai, 20092 China
| | - Jianzhong Su
- Division of Biostatistics, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030 USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030 USA
| | - Kaifu Chen
- Division of Biostatistics, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030 USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030 USA
| | - Benjamin Rodriguez
- Division of Biostatistics, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030 USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030 USA
| | - Wei Li
- Division of Biostatistics, Dan L Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030 USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030 USA
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20
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Genetic variation is associated with RTN4R expression and working memory processing in healthy humans. Brain Res Bull 2017; 134:162-167. [PMID: 28755979 DOI: 10.1016/j.brainresbull.2017.07.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 07/19/2017] [Accepted: 07/23/2017] [Indexed: 02/01/2023]
Abstract
The Nogo receptor (NgR) is implicated in neurodevelopmental processes and it participates in inhibiting axonal growth. Consistent with its high levels of expression in the prefrontal cortex, animal studies indicate that NgR is relevant for prefrontal-related cognitive processing. Given that genetic variation may alter mechanisms of gene expression impacting molecular and systems-level phenotypes, we investigated the association of genetic variation with the expression of the NgR coding gene (RTN4R), as well as with prefrontal correlates at progressively greater biological distance from gene effects. First, we studied the association of single nucleotide polymorphisms (SNPs) with RTN4R mRNA expression in postmortem prefrontal cortex of humans without psychiatric illnesses. Then, we probed in peripheral blood mononuclear cells (PBMCs) the association that we found in prefrontal tissue. Thus, we investigated whether functional genetic variation affecting RTN4R expression is also associated with prefrontal activity during working memory. We found that rs696884 (A/G) predicted these phenotypes. Specifically, the AA genotype was associated with lower RTN4R mRNA expression levels in the prefrontal cortex and PBMCs and inefficient prefrontal activity during working memory compared to the GG genotype. These results suggest that genetic variation associated with RTN4R mRNA expression influences prefrontal physiology in healthy individuals. Furthermore, they highlight the need for further investigations of the role of NgR in the pathophysiology of brain disorders associated with prefrontal dysfunction.
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21
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Achinger-Kawecka J, Taberlay PC, Clark SJ. Alterations in Three-Dimensional Organization of the Cancer Genome and Epigenome. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2017; 81:41-51. [PMID: 28424341 DOI: 10.1101/sqb.2016.81.031013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The structural and functional basis of the genome is provided by the three-dimensional (3D) chromatin state. To enable accurate gene regulation, enhancer elements and promoter regions are brought into close spatial proximity to ensure proper, cell type-specific gene expression. In cancer, genetic and epigenetic processes can deregulate the transcriptional program. To investigate whether the 3D chromatin state is also disrupted in cancer we performed Hi-C chromosome conformation sequencing in normal and prostate cancer cells and compared the chromatin interaction maps with changes to the genome and epigenome. Notably, we find that additional topologically associated domain (TAD) boundaries are formed in cancer cells resulting in smaller TADs and altered gene expression profiles. The new TAD boundaries are commonly associated with copy-number changes observed in the cancer genome. We also identified new cancer-specific chromatin loops within TADs that are enriched for enhancers and promoters. Finally, we find that many of the long-range epigenetically silenced (LRES) and long-range epigenetically active (LREA) regions in cancer are characterized by differential chromatin interactions. Together our data provide a new insight into charting alterations in higher-order structure and the relationship with genetic, epigenetic, and transcriptional changes across the cancer genome.
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Affiliation(s)
- Joanna Achinger-Kawecka
- Epigenetics Research Laboratory, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia.,St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
| | - Phillippa C Taberlay
- Epigenetics Research Laboratory, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia.,St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, New South Wales 2010, Australia.,School of Medicine, Faculty of Health, University of Tasmania, Hobart, Tasmania 7000, Australia
| | - Susan J Clark
- Epigenetics Research Laboratory, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia.,St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
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22
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Liu H, Leslie EJ, Carlson JC, Beaty TH, Marazita ML, Lidral AC, Cornell RA. Identification of common non-coding variants at 1p22 that are functional for non-syndromic orofacial clefting. Nat Commun 2017; 8:14759. [PMID: 28287101 PMCID: PMC5355807 DOI: 10.1038/ncomms14759] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 01/30/2017] [Indexed: 01/29/2023] Open
Abstract
Genome-wide association studies (GWAS) do not distinguish between single nucleotide polymorphisms (SNPs) that are causal and those that are merely in linkage-disequilibrium with causal mutations. Here we describe a versatile, functional pipeline and apply it to SNPs at 1p22, a locus identified in several GWAS for non-syndromic cleft lip with or without cleft palate (NS CL/P). First we amplified DNA elements containing the ten most-highly risk-associated SNPs and tested their enhancer activity in vitro, identifying three SNPs with allele-dependent effects on such activity. We then used in vivo reporter assays to test the tissue-specificity of these enhancers, chromatin configuration capture to test enhancer-promoter interactions, and genome editing in vitro to show allele-specific effects on ARHGAP29 expression and cell migration. Our results further indicate that two SNPs affect binding of CL/P-associated transcription factors, and one affects chromatin configuration. These results translate risk into potential mechanisms of pathogenesis.
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Affiliation(s)
- Huan Liu
- Department of Anatomy and Cell Biology, College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory for Oral Biomedicine of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei 430079, China
| | - Elizabeth J. Leslie
- Center for Craniofacial and Dental Genetics, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
| | - Jenna C. Carlson
- Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Terri H. Beaty
- Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Mary L. Marazita
- Center for Craniofacial and Dental Genetics, Department of Oral Biology, School of Dental Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
- Department of Human Genetics, Graduate School of Public Health and Clinical and Translational Science Institute, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
| | - Andrew C. Lidral
- Department of Orthodontics, College of Dentistry, University of Iowa, Iowa City, Iowa 52246, USA
| | - Robert A. Cornell
- Department of Anatomy and Cell Biology, College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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23
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Fuchs O, Gorlanova O, Latzin P, Schmidt A, Schieck M, Toncheva AA, Michel S, Gaertner VD, Kabesch M, Frey U. 6q12 and 11p14 variants are associated with postnatal exhaled nitric oxide levels and respiratory symptoms. J Allergy Clin Immunol 2017; 140:1015-1023. [PMID: 28109725 DOI: 10.1016/j.jaci.2016.11.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 11/04/2016] [Accepted: 11/14/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Exhaled nitric oxide (eNO) is a biomarker of airway inflammation and seems to precede respiratory symptoms, such as asthma, in childhood. Identifying genetic determinants of postnatal eNO levels might aid in unraveling the role of eNO in epithelial function or airway inflammation and disease. OBJECTIVE We sought to identify genetic determinants of early postnatal eNO levels and subsequent respiratory symptoms during the first year of life. METHODS Within a population-based birth cohort, eNO levels were measured in healthy term infants aged 5 weeks during quiet tidal breathing in unsedated sleep. We assessed associations of single nucleotide polymorphisms with eNO levels in a genome-wide association study and subsequent symptoms of lower respiratory tract infections during the first year of life and asked whether this was modified by prenatal and early-life environmental factors. RESULTS We identified thus far unknown determinants of infant eNO levels: rs208515 (P = 3.3 × 10-8), which is located at 6q12, probably acting in "trans" and explaining 10.3% of eNO level variance, and rs1441519 (P = 1.6 × 10-6), which is located at 11p14, potentially affecting nitric oxide synthase 3 (NOS3) expression, as shown by means of in vitro functional analyses. Moreover, the 6q12 locus was inversely associated with subsequent respiratory symptoms (P < .05) and time to recovery after first respiratory symptoms during the first year of life (P < .05). CONCLUSION The identification of novel genetic determinants of infant eNO levels might implicate that postnatal eNO metabolism in healthy infants before first viral infections and sensitization is related to mechanisms other than those associated with asthma, atopy, or increased risk thereof later in life.
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Affiliation(s)
- Oliver Fuchs
- University Children's Hospital (UKBB), University of Basel, Basel, Switzerland; Dr von Hauner Children's Hospital, Ludwig-Maximilians-Universität, Munch, and the Comprehensive Pneumology Center Munich (CPC-M; Member of the German Center for Lung Research [DZL]), Munich, Germany; Division of Respiratory Medicine, Department of Pediatrics, Inselspital, University of Bern, Bern, Switzerland
| | - Olga Gorlanova
- University Children's Hospital (UKBB), University of Basel, Basel, Switzerland
| | - Philipp Latzin
- University Children's Hospital (UKBB), University of Basel, Basel, Switzerland; Division of Respiratory Medicine, Department of Pediatrics, Inselspital, University of Bern, Bern, Switzerland
| | - Anne Schmidt
- University Children's Hospital (UKBB), University of Basel, Basel, Switzerland
| | - Maximilian Schieck
- Department of Pediatric Pneumology and Allergy, University Children's Hospital Regensburg (KUNO), Regensburg, Germany; Institute of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Antoaneta A Toncheva
- Department of Pediatric Pneumology and Allergy, University Children's Hospital Regensburg (KUNO), Regensburg, Germany
| | - Sven Michel
- Department of Pediatric Pneumology and Allergy, University Children's Hospital Regensburg (KUNO), Regensburg, Germany
| | - Vincent D Gaertner
- Department of Pediatric Pneumology and Allergy, University Children's Hospital Regensburg (KUNO), Regensburg, Germany
| | - Michael Kabesch
- Department of Pediatric Pneumology and Allergy, University Children's Hospital Regensburg (KUNO), Regensburg, Germany; Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany, and Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Germany (member of the German Center for Lung Research [DZL]), Hannover, Germany
| | - Urs Frey
- University Children's Hospital (UKBB), University of Basel, Basel, Switzerland.
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Abstract
Recent advances in chromosome conformation capture technologies are improving the current appreciation of how 3D genome architecture affects its function in different cell types and disease. Long-range chromatin interactions are organized into topologically associated domains, which are known to play a role in constraining gene expression patterns. However, in cancer cells there are alterations in the 3D genome structure, which impacts on gene regulation. Disruption of topologically associated domains architecture can result in alterations in chromatin interactions that bring new regulatory elements and genes together, leading to altered expression of oncogenes and tumor suppressor genes. Here, we discuss the impact of genetic and epigenetic changes in cancer and how this affects the spatial organization of chromatin. Understanding how disruptions to the 3D architecture contribute to the cancer genome will provide novel insights into the principles of epigenetic gene regulation in cancer and mechanisms responsible for cancer associated mutations and rearrangements.
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Affiliation(s)
- Joanna Achinger-Kawecka
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010, Australia
- St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, NSW 2010, Australia
| | - Susan J Clark
- Epigenetics Research Laboratory, Genomics & Epigenetics Division, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010, Australia
- St. Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, NSW 2010, Australia
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25
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Abstract
The kollerin complex, consisting of Scc2/Scc4 in yeast and Nipbl/Mau2 in vertebrates, is crucial for the chromatin-association of the cohesin complex and therefore for the critical functions of cohesin in cell division, transcriptional regulation and chromatin organisation. Despite the recent efforts to determine the genomic localization of the kollerin complex in different cell lines, major questions still remain unresolved, for instance where cohesin is actually loaded onto chromatin. Further, Nipbl seems to have also additional roles, for instance as transcription factor.This chapter summarizes our current knowledge on kollerin function and the recent studies on the genomic localization of Scc2, highlighting and critically discussing controversial data.
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Affiliation(s)
- Kerstin S Wendt
- Department of Cell Biology, Erasmus MC, Faculty Building, Room Ee1020, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands.
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26
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Schuyler RP, Merkel A, Raineri E, Altucci L, Vellenga E, Martens JHA, Pourfarzad F, Kuijpers TW, Burden F, Farrow S, Downes K, Ouwehand WH, Clarke L, Datta A, Lowy E, Flicek P, Frontini M, Stunnenberg HG, Martín-Subero JI, Gut I, Heath S. Distinct Trends of DNA Methylation Patterning in the Innate and Adaptive Immune Systems. Cell Rep 2016; 17:2101-2111. [PMID: 27851971 PMCID: PMC5889099 DOI: 10.1016/j.celrep.2016.10.054] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/17/2016] [Accepted: 09/12/2016] [Indexed: 01/15/2023] Open
Abstract
DNA methylation and the localization and post-translational modification of nucleosomes are interdependent factors that contribute to the generation of distinct phenotypes from genetically identical cells. With 112 whole-genome bisulfite sequencing datasets from the BLUEPRINT Epigenome Project, we analyzed the global development of DNA methylation patterns during lineage commitment and maturation of a range of immune system effector cells and the cancers that arise from them. We show clear trends in methylation patterns that are distinct in the innate and adaptive arms of the human immune system, both globally and in relation to consistently positioned nucleosomes. Most notable are a progressive loss of methylation in developing lymphocytes and the consistent occurrence of non-CG methylation in specific cell types. Cancer samples from the two lineages are further polarized, suggesting the involvement of distinct lineage-specific epigenetic mechanisms. We anticipate broad utility for this resource as a basis for further comparative epigenetic analyses.
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Affiliation(s)
- Ronald P Schuyler
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, Barcelona 08028, Spain; Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain
| | - Angelika Merkel
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, Barcelona 08028, Spain; Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain
| | - Emanuele Raineri
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, Barcelona 08028, Spain; Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain
| | - Lucia Altucci
- Dipartimento di Biochimica Biofisica e Patologia Generale, Seconda Università degli Studi di Napoli, Vico Luigi de Crecchio 7, Napoli 80138, Italy
| | - Edo Vellenga
- Department of Hematology, University of Groningen and University Medical Center Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands
| | - Joost H A Martens
- Department of Molecular Biology, Radboud University, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, 6500 HB Nijmegen, the Netherlands
| | - Farzin Pourfarzad
- Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Plesmanlaan 125, 1066 CX Amsterdam, the Netherlands
| | - Taco W Kuijpers
- Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Plesmanlaan 125, 1066 CX Amsterdam, the Netherlands; Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Frances Burden
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK; National Health Service (NHS) Blood and Transplant, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK
| | - Samantha Farrow
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK; National Health Service (NHS) Blood and Transplant, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK
| | - Kate Downes
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK; National Health Service (NHS) Blood and Transplant, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK
| | - Willem H Ouwehand
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK; National Health Service (NHS) Blood and Transplant, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK; British Heart Foundation Centre of Excellence, University of Cambridge, Cambridge Biomedical Campus, Long Road, CB2 0QQ Cambridge, UK; Department of Human Genetics, The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, CB10 1HH Cambridge, UK
| | - Laura Clarke
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD Cambridge, UK
| | - Avik Datta
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD Cambridge, UK
| | - Ernesto Lowy
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD Cambridge, UK
| | - Paul Flicek
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, CB10 1SD Cambridge, UK
| | - Mattia Frontini
- Department of Haematology, University of Cambridge, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK; National Health Service (NHS) Blood and Transplant, Cambridge Biomedical Campus, Long Road, CB2 0PT Cambridge, UK; British Heart Foundation Centre of Excellence, University of Cambridge, Cambridge Biomedical Campus, Long Road, CB2 0QQ Cambridge, UK
| | - Hendrik G Stunnenberg
- Department of Molecular Biology, Radboud University, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, 6500 HB Nijmegen, the Netherlands
| | - José I Martín-Subero
- Department of Anatomic Pathology, Pharmacology and Microbiology, University of Barcelona, Institut d'Investigacions Biomédiques August Pi i Sunyer (IDIBAPS), Barcelona 08036, Spain
| | - Ivo Gut
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, Barcelona 08028, Spain; Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain
| | - Simon Heath
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Baldiri i Reixac 4, Barcelona 08028, Spain; Universitat Pompeu Fabra (UPF), Barcelona 08002, Spain.
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Neme A, Nurminen V, Seuter S, Carlberg C. The vitamin D-dependent transcriptome of human monocytes. J Steroid Biochem Mol Biol 2016; 164:180-187. [PMID: 26523676 DOI: 10.1016/j.jsbmb.2015.10.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/05/2015] [Accepted: 10/25/2015] [Indexed: 11/28/2022]
Abstract
Monocytes are important cells of the innate immune system that can differentiate into macrophages and dendritic cells. The biologically active form of vitamin D, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), serves as a ligand of the nuclear receptor vitamin D receptor (VDR). A key physiological function of 1,25(OH)2D3 is the defense against pathogens, such as those causing tuberculosis, that involves the modulation of the monocyte transcriptome. THP-1 cells are an established model of human monocytes, for which the at present largest set of 1,25(OH)2D3-affected genome-wide data are available. Here we summarize the insight obtained from the recent transcriptome of 1,25(OH)2D3-stimulated THP-1 cells, that was determined by triplicate RNA sequencing (RNA-seq). Primary and secondary vitamin D target genes being up- and down-regulated were related to changes in the epigenome of THP-1 cells, such as 1,25(OH)2D3-dependent chromatin opening and modulation of the genome-wide association of the transcription factors VDR and CCCTC-binding factor (CTCF) with their respective genomic binding sites. The anti-microbial response is the top-ranking early physiological function represented by 1,25(OH)2D3-stimulated genomic regions and genes, but also other immunity-related pathways, such as IL10 signaling, are activated. Taken together, the epigenomic and transcriptomic responses of THP-1 cells to 1,25(OH)2D3 represent a master example of the impact of vitamin D on human physiology.
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Affiliation(s)
- Antonio Neme
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, FI-70211 Kuopio, Finland
| | - Veijo Nurminen
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, FI-70211 Kuopio, Finland
| | - Sabine Seuter
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, FI-70211 Kuopio, Finland
| | - Carsten Carlberg
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, FI-70211 Kuopio, Finland.
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28
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Glinsky GV. Mechanistically Distinct Pathways of Divergent Regulatory DNA Creation Contribute to Evolution of Human-Specific Genomic Regulatory Networks Driving Phenotypic Divergence of Homo sapiens. Genome Biol Evol 2016; 8:2774-88. [PMID: 27503290 PMCID: PMC5630920 DOI: 10.1093/gbe/evw185] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Thousands of candidate human-specific regulatory sequences (HSRS) have been identified, supporting the hypothesis that unique to human phenotypes result from human-specific alterations of genomic regulatory networks. Collectively, a compendium of multiple diverse families of HSRS that are functionally and structurally divergent from Great Apes could be defined as the backbone of human-specific genomic regulatory networks. Here, the conservation patterns analysis of 18,364 candidate HSRS was carried out requiring that 100% of bases must remap during the alignments of human, chimpanzee, and bonobo sequences. A total of 5,535 candidate HSRS were identified that are: (i) highly conserved in Great Apes; (ii) evolved by the exaptation of highly conserved ancestral DNA; (iii) defined by either the acceleration of mutation rates on the human lineage or the functional divergence from non-human primates. The exaptation of highly conserved ancestral DNA pathway seems mechanistically distinct from the evolution of regulatory DNA segments driven by the species-specific expansion of transposable elements. Genome-wide proximity placement analysis of HSRS revealed that a small fraction of topologically associating domains (TADs) contain more than half of HSRS from four distinct families. TADs that are enriched for HSRS and termed rapidly evolving in humans TADs (revTADs) comprise 0.8–10.3% of 3,127 TADs in the hESC genome. RevTADs manifest distinct correlation patterns between placements of human accelerated regions, human-specific transcription factor-binding sites, and recombination rates. There is a significant enrichment within revTAD boundaries of hESC-enhancers, primate-specific CTCF-binding sites, human-specific RNAPII-binding sites, hCONDELs, and H3K4me3 peaks with human-specific enrichment at TSS in prefrontal cortex neurons (P < 0.0001 in all instances). Present analysis supports the idea that phenotypic divergence of Homo sapiens is driven by the evolution of human-specific genomic regulatory networks via at least two mechanistically distinct pathways of creation of divergent sequences of regulatory DNA: (i) recombination-associated exaptation of the highly conserved ancestral regulatory DNA segments; (ii) human-specific insertions of transposable elements.
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Affiliation(s)
- Gennadi V Glinsky
- Institute of Engineering in Medicine, University of California-San Diego
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29
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Delvaux E, Mastroeni D, Nolz J, Coleman PD. Novel method to ascertain chromatin accessibility at specific genomic loci from frozen brain homogenates and laser capture microdissected defined cells. ACTA ACUST UNITED AC 2016; 6:1-9. [PMID: 27158594 DOI: 10.1016/j.nepig.2016.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
We describe a novel method for assessing the "open" or "closed" state of chromatin at selected locations within the genome. This method combines the use of Benzonase, which can digest DNA in the presence of actin, with qPCR to define digested regions. We demonstrate the application of this method in brain homogenates and laser captured cells. We also demonstrate application to selected sites within more than one gene and multiple sites within one gene. We demonstrate the validity of the method by treating cells with valproate, known to render chromatin more permissive, and by comparison with classical digestion with DNase I in an in vitro preparation. Although we demonstrate the use of this method in brain tissue we also recognize its applicability to other tissue types.
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Affiliation(s)
- Elaine Delvaux
- ASU-Banner Neurodegenerative Disease Research Center, Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, AZ, USA; L.J. Roberts Center for Alzheimer's Research, Banner Sun Health Research Institute, 10515 W Santa Fe Dr, Sun City, AZ 85351, USA
| | - Diego Mastroeni
- ASU-Banner Neurodegenerative Disease Research Center, Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, AZ, USA; L.J. Roberts Center for Alzheimer's Research, Banner Sun Health Research Institute, 10515 W Santa Fe Dr, Sun City, AZ 85351, USA; Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Faculty of Health, Medicine and Life Sciences, European Graduate School of Neuroscience (EURON), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Jennifer Nolz
- ASU-Banner Neurodegenerative Disease Research Center, Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, AZ, USA; L.J. Roberts Center for Alzheimer's Research, Banner Sun Health Research Institute, 10515 W Santa Fe Dr, Sun City, AZ 85351, USA
| | - Paul D Coleman
- ASU-Banner Neurodegenerative Disease Research Center, Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, AZ, USA; L.J. Roberts Center for Alzheimer's Research, Banner Sun Health Research Institute, 10515 W Santa Fe Dr, Sun City, AZ 85351, USA
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30
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Seuter S, Neme A, Carlberg C. Epigenome-wide effects of vitamin D and their impact on the transcriptome of human monocytes involve CTCF. Nucleic Acids Res 2016; 44:4090-104. [PMID: 26715761 PMCID: PMC4872072 DOI: 10.1093/nar/gkv1519] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 12/15/2015] [Accepted: 12/19/2015] [Indexed: 11/13/2022] Open
Abstract
The physiological functions of vitamin D are mediated by its metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) activating the transcription factor vitamin D receptor (VDR). In THP-1 human monocytes we demonstrated epigenome-wide effects of 1,25(OH)2D3 at 8979 loci with significantly modulated chromatin accessibility. Maximal chromatin opening was observed after 24 h, while after 48 h most sites closed again. The chromatin-organizing protein CTCF bound to 14% of the 1,25(OH)2D3-sensitive chromatin regions. Interestingly, 1,25(OH)2D3 affected the chromatin association of CTCF providing an additional mechanism for the epigenome-wide effects of the VDR ligand. The 1,25(OH)2D3-modulated transcriptome of THP-1 cells comprised 1284 genes, 77.5% of which responded only 24 h after stimulation. During the 1,25(OH)2D3 stimulation time course the proportion of down-regulated genes increased from 0% to 44.9% and the top-ranking physiological function of the respective genes shifted from anti-microbial response to connective tissue disorders. The integration of epigenomic and transcriptomic data identified 165 physiologically important 1,25(OH)2D3 target genes, including HTT and NOD2, whose expression can be predicted primarily from epigenomic data of their genomic loci. Taken together, a large number of 1,25(OH)2D3-triggered epigenome-wide events precede and accompany the transcriptional activation of target genes of the nuclear hormone.
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Affiliation(s)
- Sabine Seuter
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, FI-70211 Kuopio, Finland
| | - Antonio Neme
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, FI-70211 Kuopio, Finland
| | - Carsten Carlberg
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, FI-70211 Kuopio, Finland
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31
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Wang J, Meng X, Chen H, Yuan C, Li X, Zhou Y, Chen M. Exploring the mechanisms of genome-wide long-range interactions: interpreting chromosome organization. Brief Funct Genomics 2016; 15:385-95. [PMID: 26769147 DOI: 10.1093/bfgp/elv062] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Developments in chromosome conformation capture (3C) technologies have revealed that the three-dimensional organization of a genome leads widely separated functional elements to reside in close proximity. However, the mechanisms responsible for mediating long-range interactions are still not completely known. In this review, we firstly evaluate and compare the current seven 3C-based methods, summarize their advantages and discuss their limitations to our current understanding of genome structure. Then, software packages available to perform the analysis of 3C-based data are described. Moreover, we review the insights into the two main mechanisms of long-range interactions, which regulate gene expression by bringing together promoters and distal regulatory elements and by creating structural domains that contain functionally related genes with similar expression landscape. At last, we summarize what is known about the mediating factors involved in stimulation/repression of long-range interactions, such as transcription factors and noncoding RNAs.
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32
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Shavit Y, Merelli I, Milanesi L, Lio’ P. How computer science can help in understanding the 3D genome architecture. Brief Bioinform 2015; 17:733-44. [DOI: 10.1093/bib/bbv085] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Indexed: 01/20/2023] Open
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Abstract
Recent investigations on 3D chromatin folding revealed that the eukaryote genomes are both highly compartmentalized and extremely dynamic. This review presents the most recent advances in topological domains' organization of the eukaryote genomes and discusses the relationship to chromatin loop formation. CTCF protein appears as a central factor of these two organization levels having either a strong insulating role at TAD borders, or a weaker architectural role in chromatin loop formation. TAD borders directly impact on chromatin dynamics by restricting contacts within specific genomic portions thus confining chromatin loop formation within TADs. We discuss how sub-TAD chromatin dynamics, constrained into a recently described statistical helix conformation, can produce functional interactions by contact stabilization.
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Abstract
Female mammalian cells compensate dosage of X-linked gene expression through the inactivation of one of their two X chromosomes. X chromosome inactivation (XCI) in eutherians is dependent on the non-coding RNA Xist that is up-regulated from the future inactive X chromosome, coating it and recruiting factors involved in silencing and altering its chromatin state. Xist lies within the X-inactivation center (Xic), a region on the X that is required for XCI, and is regulated in cis by elements on the X chromosome and in trans by diffusible factors. In this review, we summarize the latest results in cis- and trans-regulation of the Xic. We discuss how the organization of the Xic in topologically associating domains is important for XCI (cis-regulation) and how proteins in the pluripotent state and upon development or differentiation of embryonic stem cells control proper inactivation of one X chromosome (trans-regulation).
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Evolutionary comparison reveals that diverging CTCF sites are signatures of ancestral topological associating domains borders. Proc Natl Acad Sci U S A 2015; 112:7542-7. [PMID: 26034287 DOI: 10.1073/pnas.1505463112] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Increasing evidence in the last years indicates that the vast amount of regulatory information contained in mammalian genomes is organized in precise 3D chromatin structures. However, the impact of this spatial chromatin organization on gene expression and its degree of evolutionary conservation is still poorly understood. The Six homeobox genes are essential developmental regulators organized in gene clusters conserved during evolution. Here, we reveal that the Six clusters share a deeply evolutionarily conserved 3D chromatin organization that predates the Cambrian explosion. This chromatin architecture generates two largely independent regulatory landscapes (RLs) contained in two adjacent topological associating domains (TADs). By disrupting the conserved TAD border in one of the zebrafish Six clusters, we demonstrate that this border is critical for preventing competition between promoters and enhancers located in separated RLs, thereby generating different expression patterns in genes located in close genomic proximity. Moreover, evolutionary comparison of Six-associated TAD borders reveals the presence of CCCTC-binding factor (CTCF) sites with diverging orientations in all studied deuterostomes. Genome-wide examination of mammalian HiC data reveals that this conserved CTCF configuration is a general signature of TAD borders, underscoring that common organizational principles underlie TAD compartmentalization in deuterostome evolution.
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36
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Boulos RE, Drillon G, Argoul F, Arneodo A, Audit B. Structural organization of human replication timing domains. FEBS Lett 2015; 589:2944-57. [PMID: 25912651 DOI: 10.1016/j.febslet.2015.04.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 12/16/2022]
Abstract
Recent analysis of genome-wide epigenetic modification data, mean replication timing (MRT) profiles and chromosome conformation data in mammals have provided increasing evidence that flexibility in replication origin usage is regulated locally by the epigenetic landscape and over larger genomic distances by the 3D chromatin architecture. Here, we review the recent results establishing some link between replication domains and chromatin structural domains in pluripotent and various differentiated cell types in human. We reconcile the originally proposed dichotomic picture of early and late constant timing regions that replicate by multiple rather synchronous origins in separated nuclear compartments of open and closed chromatins, with the U-shaped MRT domains bordered by "master" replication origins specified by a localized (∼200-300 kb) zone of open and transcriptionally active chromatin from which a replication wave likely initiates and propagates toward the domain center via a cascade of origin firing. We discuss the relationships between these MRT domains, topologically associated domains and lamina-associated domains. This review sheds a new light on the epigenetically regulated global chromatin reorganization that underlies the loss of pluripotency and the determination of differentiation properties.
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Affiliation(s)
- Rasha E Boulos
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Guénola Drillon
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Françoise Argoul
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Alain Arneodo
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France
| | - Benjamin Audit
- Université de Lyon, F-69000 Lyon, France; Laboratoire de Physique, CNRS UMR5672, Ecole Normale Supérieure de Lyon, F-69007 Lyon, France.
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Hofmann A, Heermann DW. The role of loops on the order of eukaryotes and prokaryotes. FEBS Lett 2015; 589:2958-65. [PMID: 25912650 DOI: 10.1016/j.febslet.2015.04.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 04/14/2015] [Accepted: 04/14/2015] [Indexed: 11/29/2022]
Abstract
The study of the three-dimensional organization of chromatin has recently gained much focus in the context of novel techniques for detecting genome-wide contacts using next-generation sequencing. These chromosome conformation capture-based methods give a deep topological insight into the architecture of the genome inside the nucleus. Several recent studies observe a compartmentalization of chromatin interactions into spatially confined domains. This structural feature of interphase chromosomes is not only supported by conventional studies assessing the interaction data of millions of cells, but also by analysis on the level of a single cell. We first present and examine the different models that have been proposed to elucidate these topological domains in eukaryotes. Then we show that a model which relies on the dynamic formation of loops within domains can account for the experimentally observed contact maps. Interestingly, the topological domain structure is not only found in mammalian genomes, but also in bacterial chromosomes.
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Affiliation(s)
- Andreas Hofmann
- Institute for Theoretical Physics, University of Heidelberg, Philosophenweg 19, 69120 Heidelberg, Germany.
| | - Dieter W Heermann
- Institute for Theoretical Physics, University of Heidelberg, Philosophenweg 19, 69120 Heidelberg, Germany; Institute for Molecular Biophysics, The Jackson Laboratory, Bar Harbor, ME, USA; Shanghai Institute of Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai, PR China; Shanghai Center for Bioinformation Technology (SCBIT), Shanghai, PR China
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38
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Venkatraman B, Klenova E. Role of CTCF poly(ADP-Ribosyl)ation in the regulation of apoptosis in breast cancer cells. Indian J Med Paediatr Oncol 2015; 36:49-54. [PMID: 25810575 PMCID: PMC4363851 DOI: 10.4103/0971-5851.151784] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
INTRODUCTION CTCF is a candidate tumor suppressor gene encoding a multifunctional transcription factor. CTCF function is controlled by posttranslational modification and interaction with other proteins. Research findings suggested that CTCF function can be regulated by poly(ADP-ribosyl)ation (PARlation) and has specific anti-apoptotic function in breast cancer cells. The aim of this study is to assess the effect of CTCF-wild type (WT) and CTCF complete mutant, which is deficient of PARlation in regulating apoptosis in breast cancer cells. MATERIALS AND METHODS The effect of CTCF-WT and CTCF complete mutant was expressed in breast cancer cell-lines by DNA-mediated transfection technique monitored by enhanced green fluorescent protein fluorescence. Evaluation of apoptotic cell death was carried out with immunohistochemical staining using 4'-6'-diamino-2 phenylindole and scoring by fluorescent microscopy. RESULTS CTCF-WT supports survival of breast cancer cells and was observed that CTCF complete mutant interferes with the functions of the CTCF-WT and there was a considerable apoptotic cell death in the breast cancer cell lines such as MDA-MB-435, CAMA-1 and MCF-7. CONCLUSION The study enlighten CTCF as a Biological Marker for breast cancer and the role of CTCF PARlation may be involved in breast carcinogenesis.
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Affiliation(s)
- Bhooma Venkatraman
- Australian School of Advanced Medicine, Macquarie University, Sydney, Australia
| | - Elena Klenova
- School of Biological Sciences, University of Essex, United Kingdom
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39
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Liu L, Heermann DW. The interaction of DNA with multi-Cys2His2 zinc finger proteins. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:064107. [PMID: 25563438 DOI: 10.1088/0953-8984/27/6/064107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The multi-Cys2His2 (mC2H2) zinc finger protein, like CTCF, plays a central role in the three-dimensional organization of chromatin and gene regulation. The interaction between DNA and mC2H2 zinc finger proteins becomes crucial to better understand how CTCF dynamically shapes the chromatin structure. Here, we study a coarse-grained model of the mC2H2 zinc finger proteins in complexes with DNA, and in particular, we study how a mC2H2 zinc finger protein binds to and searches for its target DNA loci. On the basis of coarse-grained molecular dynamics simulations, we present several interesting kinetic conformational properties of the proteins, such as the rotation-coupled sliding, the asymmetrical roles of different zinc fingers and the partial binding partial dangling mode. In addition, two kinds of studied mC2H2 zinc finger proteins, of CG-rich and AT-rich binding motif each, were able to recognize their target sites and slide away from their non-target sites, which shows a proper sequence specificity in our model and the derived force field for mC2H2-DNA interaction. A further application to CTCF shows that the protein binds to a specific DNA duplex only with its central zinc fingers. The zinc finger domains of CTCF asymmetrically bend the DNA, but do not form a DNA loop alone in our simulations.
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Affiliation(s)
- Lei Liu
- Institute for Theoretical Physics, Heidelberg University, 69117 Heidelberg, Germany
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40
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Sancho A, Li S, Paul T, Zhang F, Aguilo F, Vashisht A, Balasubramaniyan N, Leleiko NS, Suchy FJ, Wohlschlegel JA, Zhang W, Walsh MJ. CHD6 regulates the topological arrangement of the CFTR locus. Hum Mol Genet 2015; 24:2724-32. [PMID: 25631877 DOI: 10.1093/hmg/ddv032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/26/2015] [Indexed: 01/19/2023] Open
Abstract
The control of transcription is regulated through the well-coordinated spatial and temporal interactions between distal genomic regulatory elements required for specialized cell-type and developmental gene expression programs. With recent findings CFTR has served as a model to understand the principles that govern genome-wide and topological organization of distal intra-chromosomal contacts as it relates to transcriptional control. This is due to the extensive characterization of the DNase hypersensitivity sites, modification of chromatin, transcription factor binding sites and the arrangement of these sites in CFTR consistent with the restrictive expression in epithelial cell types. Here, we identified CHD6 from a screen among several chromatin-remodeling proteins as a putative epigenetic modulator of CFTR expression. Moreover, our findings of CTCF interactions with CHD6 are consistent with the role described previously for CTCF in CFTR regulation. Our results now reveal that the CHD6 protein lies within the infrastructure of multiple transcriptional complexes, such as the FACT, PBAF, PAF1C, Mediator, SMC/Cohesion and MLL complexes. This model underlies the fundamental role CHD6 facilitates by tethering cis-acting regulatory elements of CFTR in proximity to these multi-subunit transcriptional protein complexes. Finally, we indicate that CHD6 structurally coordinates a three-dimensional stricture between intragenic elements of CFTR bound by several cell-type specific transcription factors, such as CDX2, SOX18, HNF4α and HNF1α. Therefore, our results reveal new insights into the epigenetic regulation of CFTR expression, whereas the manipulation of CFTR gene topology could be considered for treating specific indications of cystic fibrosis and/or pancreatitis.
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Affiliation(s)
- Ana Sancho
- Departments of Pediatrics, Structural and Chemical Biology
| | | | - Thankam Paul
- Department of Paediatrics, St. George's Hospital, University of London, London SW17 0QT, UK
| | - Fan Zhang
- Laboratory of Bioinformatics, Division of Nephrology, Department of Medicine
| | | | - Ajay Vashisht
- Department of Biological Chemistry and the Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Natarajan Balasubramaniyan
- Children's Hospital Research Institute of Colorado, University of Colorado School of Medicine, Aurora, CO 80045, USA and
| | - Neal S Leleiko
- Department of Pediatrics, Division of Gastroenterology, Hasbro Children's Hospital, Brown University School of Medicine, Providence, NY, USA
| | - Frederick J Suchy
- Children's Hospital Research Institute of Colorado, University of Colorado School of Medicine, Aurora, CO 80045, USA and
| | - James A Wohlschlegel
- Department of Biological Chemistry and the Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Weijia Zhang
- Laboratory of Bioinformatics, Division of Nephrology, Department of Medicine
| | - Martin J Walsh
- Departments of Pediatrics, Structural and Chemical Biology, Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA,
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41
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Schoborg T, Labrador M. Expanding the roles of chromatin insulators in nuclear architecture, chromatin organization and genome function. Cell Mol Life Sci 2014; 71:4089-113. [PMID: 25012699 PMCID: PMC11113341 DOI: 10.1007/s00018-014-1672-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/31/2014] [Accepted: 06/23/2014] [Indexed: 01/08/2023]
Abstract
Of the numerous classes of elements involved in modulating eukaryotic chromosome structure and function, chromatin insulators arguably remain the most poorly understood in their contribution to these processes in vivo. Indeed, our view of chromatin insulators has evolved dramatically since their chromatin boundary and enhancer blocking properties were elucidated roughly a quarter of a century ago as a result of recent genome-wide, high-throughput methods better suited to probing the role of these elements in their native genomic contexts. The overall theme that has emerged from these studies is that chromatin insulators function as general facilitators of higher-order chromatin loop structures that exert both physical and functional constraints on the genome. In this review, we summarize the result of recent work that supports this idea as well as a number of other studies linking these elements to a diverse array of nuclear processes, suggesting that chromatin insulators exert master control over genome organization and behavior.
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Affiliation(s)
- Todd Schoborg
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
- Present Address: Laboratory of Molecular Machines and Tissue Architecture, Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 50 South Dr Rm 2122, Bethesda, MD 20892 USA
| | - Mariano Labrador
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
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42
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Franco MM, Prickett AR, Oakey RJ. The role of CCCTC-binding factor (CTCF) in genomic imprinting, development, and reproduction. Biol Reprod 2014; 91:125. [PMID: 25297545 DOI: 10.1095/biolreprod.114.122945] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
CCCTC-binding factor (CTCF) is the major protein involved in insulator activity in vertebrates, with widespread DNA binding sites in the genome. CTCF participates in many processes related to global chromatin organization and remodeling, contributing to the repression or activation of gene transcription. It is also involved in epigenetic reprogramming and is essential during gametogenesis and embryo development. Abnormal DNA methylation patterns at CTCF motifs may impair CTCF binding to DNA, and are related to fertility disorders in mammals. Therefore, CTCF and its binding sites are important candidate regions to be investigated as molecular markers for gamete and embryo quality. This article reviews the role of CTCF in genomic imprinting, gametogenesis, and early embryo development and, moreover, highlights potential opportunities for environmental influences associated with assisted reproductive techniques (ARTs) to affect CTCF-mediated processes. We discuss the potential use of CTCF as a molecular marker for assessing gamete and embryo quality in the context of improving the efficiency and safety of ARTs.
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Affiliation(s)
- Maurício M Franco
- Embrapa Genetic Resources & Biotechnology, Laboratory of Animal Reproduction, Parque Estação Biológica, Brasília, Brazil
| | - Adam R Prickett
- Department of Medical & Molecular Genetics, King's College London, Guy's Hospital, London, United Kingdom
| | - Rebecca J Oakey
- Department of Medical & Molecular Genetics, King's College London, Guy's Hospital, London, United Kingdom
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43
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Sharov AA. Evolutionary constraints or opportunities? Biosystems 2014; 123:9-18. [PMID: 25047708 DOI: 10.1016/j.biosystems.2014.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/14/2014] [Accepted: 04/14/2014] [Indexed: 12/24/2022]
Abstract
Natural selection is traditionally viewed as a leading factor of evolution, whereas variation is assumed to be random and non-directional. Any order in variation is attributed to epigenetic or developmental constraints that can hinder the action of natural selection. In contrast I consider the positive role of epigenetic mechanisms in evolution because they provide organisms with opportunities for rapid adaptive change. Because the term "constraint" has negative connotations, I use the term "regulated variation" to emphasize the adaptive nature of phenotypic variation, which helps populations and species to survive and evolve in changing environments. The capacity to produce regulated variation is a phenotypic property, which is not described in the genome. Instead, the genome acts as a switchboard, where mostly random mutations switch "on" or "off" preexisting functional capacities of organism components. Thus, there are two channels of heredity: informational (genomic) and structure-functional (phenotypic). Functional capacities of organisms most likely emerged in a chain of modifications and combinations of more simple ancestral functions. The role of DNA has been to keep records of these changes (without describing the result) so that they can be reproduced in the following generations. Evolutionary opportunities include adjustments of individual functions, multitasking, connection between various components of an organism, and interaction between organisms. The adaptive nature of regulated variation can be explained by the differential success of lineages in macro-evolution. Lineages with more advantageous patterns of regulated variation are likely to produce more species and secure more resources (i.e., long-term lineage selection).
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Affiliation(s)
- Alexei A Sharov
- National Institute on Aging, Genetics Laboratory, 251 Bayview Blvd., Baltimore, MD 21224, USA.
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44
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Quintin J, Le Péron C, Palierne G, Bizot M, Cunha S, Sérandour AA, Avner S, Henry C, Percevault F, Belaud-Rotureau MA, Huet S, Watrin E, Eeckhoute J, Legagneux V, Salbert G, Métivier R. Dynamic estrogen receptor interactomes control estrogen-responsive trefoil Factor (TFF) locus cell-specific activities. Mol Cell Biol 2014; 34:2418-36. [PMID: 24752895 PMCID: PMC4054307 DOI: 10.1128/mcb.00918-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 09/03/2013] [Accepted: 04/09/2014] [Indexed: 12/28/2022] Open
Abstract
Estradiol signaling is ideally suited for analyzing the molecular and functional linkages between the different layers of information directing transcriptional regulations: the DNA sequence, chromatin modifications, and the spatial organization of the genome. Hence, the estrogen receptor (ER) can bind at a distance from its target genes and engages timely and spatially coordinated processes to regulate their expression. In the context of the coordinated regulation of colinear genes, identifying which ER binding sites (ERBSs) regulate a given gene still remains a challenge. Here, we investigated the coordination of such regulatory events at a 2-Mb genomic locus containing the estrogen-sensitive trefoil factor (TFF) cluster of genes in breast cancer cells. We demonstrate that this locus exhibits a hormone- and cohesin-dependent reduction in the plasticity of its three-dimensional organization that allows multiple ERBSs to be dynamically brought to the vicinity of estrogen-sensitive genes. Additionally, by using triplex-forming oligonucleotides, we could precisely document the functional links between ER engagement at given ERBSs and the regulation of particular genes. Hence, our data provide evidence of a formerly suggested cooperation of enhancers toward gene regulation and also show that redundancy between ERBSs can occur.
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Affiliation(s)
- Justine Quintin
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Christine Le Péron
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Gaëlle Palierne
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Maud Bizot
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Stéphanie Cunha
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Aurélien A Sérandour
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Stéphane Avner
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Catherine Henry
- Cytogenetics and Cellular Biology Department, CHU, Rennes, France
| | - Frédéric Percevault
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Marc-Antoine Belaud-Rotureau
- Cytogenetics and Cellular Biology Department, CHU, Rennes, France BIOSIT, UMR CNRS 6290, Université de Rennes I, Faculté de Médecine, Rennes, France
| | - Sébastien Huet
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Erwan Watrin
- Equipe CC, UMR CNRS 6290, Université de Rennes I, Faculté de Médecine, Rennes, France
| | - Jérôme Eeckhoute
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France INSERM U1011, Université Lille-Nord de France, Faculté de Médecine de Lille-Pôle Recherche, Lille, France
| | - Vincent Legagneux
- Equipe EGD, UMR CNRS 6290, Université de Rennes I, Faculté de Médecine, Rennes, France
| | - Gilles Salbert
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
| | - Raphaël Métivier
- Equipe SP@RTE, UMR CNRS 6290, Equipe Labellisée Ligue contre le Cancer, Université de Rennes I, Rennes, France
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45
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Smith OK, Aladjem MI. Chromatin structure and replication origins: determinants of chromosome replication and nuclear organization. J Mol Biol 2014; 426:3330-41. [PMID: 24905010 DOI: 10.1016/j.jmb.2014.05.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 05/22/2014] [Accepted: 05/24/2014] [Indexed: 12/29/2022]
Abstract
The DNA replication program is, in part, determined by the epigenetic landscape that governs local chromosome architecture and directs chromosome duplication. Replication must coordinate with other biochemical processes occurring concomitantly on chromatin, such as transcription and remodeling, to insure accurate duplication of both genetic and epigenetic features and to preserve genomic stability. The importance of genome architecture and chromatin looping in coordinating cellular processes on chromatin is illustrated by two recent sets of discoveries. First, chromatin-associated proteins that are not part of the core replication machinery were shown to affect the timing of DNA replication. These chromatin-associated proteins could be working in concert, or perhaps in competition, with the transcriptional machinery and with chromatin modifiers to determine the spatial and temporal organization of replication initiation events. Second, epigenetic interactions are mediated by DNA sequences that determine chromosomal replication. In this review, we summarize recent findings and current models linking spatial and temporal regulation of the replication program with epigenetic signaling. We discuss these issues in the context of the genome's three-dimensional structure with an emphasis on events occurring during the initiation of DNA replication.
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Affiliation(s)
- Owen K Smith
- DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA
| | - Mirit I Aladjem
- DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
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46
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Cohesin mutations in myeloid malignancies: underlying mechanisms. Exp Hematol Oncol 2014; 3:13. [PMID: 24904756 PMCID: PMC4046106 DOI: 10.1186/2162-3619-3-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 04/16/2014] [Indexed: 01/09/2023] Open
Abstract
Recently, whole genome sequencing approaches have pinpointed mutations in genes that were previously not associated with cancer. For Acute Myeloid Leukaemia (AML), and other myeloid disorders, these approaches revealed a high prevalence of mutations in genes encoding the chromosome cohesion complex, cohesin. Cohesin mutations represent a novel genetic pathway for AML, but how AML arises from these mutations is unknown. This review will explore the potential mechanisms by which cohesin mutations contribute to AML and other myeloid malignancies.
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47
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Sharov AA. WITHDRAWN: Evolutionary constraints or opportunities? Biosystems 2014. [DOI: 10.1016/j.biosystems.2014.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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48
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Sharov AA. Evolutionary constraints or opportunities? Biosystems 2014; 120C:21-30. [PMID: 24769155 PMCID: PMC4206685 DOI: 10.1016/j.biosystems.2014.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/14/2014] [Accepted: 04/14/2014] [Indexed: 01/05/2023]
Abstract
Natural selection is traditionally viewed as a leading factor of evolution, whereas variation is assumed to be random and non-directional. Any order in variation is attributed to epigenetic or developmental constraints that can hinder the action of natural selection. In contrast I consider the positive role of epigenetic mechanisms in evolution because they provide organisms with opportunities for rapid adaptive change. Because the term "constraint" has negative connotations, I use the term "regulated variation" to emphasize the adaptive nature of phenotypic variation, which helps populations and species to survive and evolve in changing environments. The capacity to produce regulated variation is a phenotypic property, which is not described in the genome. Instead, the genome acts as a switchboard, where mostly random mutations switch "on" or "off" preexisting functional capacities of organism components. Thus, there are two channels of heredity: informational (genomic) and structure-functional (phenotypic). Functional capacities of organisms most likely emerged in a chain of modifications and combinations of more simple ancestral functions. The role of DNA has been to keep records of these changes (without describing the result) so that they can be reproduced in the following generations. Evolutionary opportunities include adjustments of individual functions, multitasking, connection between various components of an organism, and interaction between organisms. The adaptive nature of regulated variation can be explained by the differential success of lineages in macro-evolution. Lineages with more advantageous patterns of regulated variation are likely to produce more species and secure more resources (i.e., long-term lineage selection).
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Affiliation(s)
- Alexei A Sharov
- National Institute on Aging, Genetics Laboratory, 251 Bayview Blvd., Baltimore, MD 21224, USA.
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49
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Wendt KS, Grosveld FG. Transcription in the context of the 3D nucleus. Curr Opin Genet Dev 2014; 25:62-7. [DOI: 10.1016/j.gde.2013.11.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 11/29/2013] [Indexed: 11/27/2022]
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50
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Maksimenko O, Georgiev P. Mechanisms and proteins involved in long-distance interactions. Front Genet 2014; 5:28. [PMID: 24600469 PMCID: PMC3927085 DOI: 10.3389/fgene.2014.00028] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 01/25/2014] [Indexed: 12/28/2022] Open
Abstract
Due to advances in genome-wide technologies, consistent distant interactions within chromosomes of higher eukaryotes have been revealed. In particular, it has been shown that enhancers can specifically and directly interact with promoters by looping out intervening sequences, which can be up to several hundred kilobases long. This review is focused on transcription factors that are supposed to be involved in long-range interactions. Available data are in agreement with the model that several known transcription factors and insulator proteins belong to an abundant but poorly studied class of proteins that are responsible for chromosomal architecture.
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Affiliation(s)
- Oksana Maksimenko
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences Moscow, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences Moscow, Russia
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