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The genetic architecture of DNA replication timing in human pluripotent stem cells. Nat Commun 2021; 12:6746. [PMID: 34799581 PMCID: PMC8604924 DOI: 10.1038/s41467-021-27115-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/29/2021] [Indexed: 12/11/2022] Open
Abstract
DNA replication follows a strict spatiotemporal program that intersects with chromatin structure but has a poorly understood genetic basis. To systematically identify genetic regulators of replication timing, we exploited inter-individual variation in human pluripotent stem cells from 349 individuals. We show that the human genome's replication program is broadly encoded in DNA and identify 1,617 cis-acting replication timing quantitative trait loci (rtQTLs) - sequence determinants of replication initiation. rtQTLs function individually, or in combinations of proximal and distal regulators, and are enriched at sites of histone H3 trimethylation of lysines 4, 9, and 36 together with histone hyperacetylation. H3 trimethylation marks are individually repressive yet synergistically associate with early replication. We identify pluripotency-related transcription factors and boundary elements as positive and negative regulators of replication timing, respectively. Taken together, human replication timing is controlled by a multi-layered mechanism with dozens of effectors working combinatorially and following principles analogous to transcription regulation.
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Utani K, Fu H, Jang SM, Marks AB, Smith OK, Zhang Y, Redon CE, Shimizu N, Aladjem MI. Phosphorylated SIRT1 associates with replication origins to prevent excess replication initiation and preserve genomic stability. Nucleic Acids Res 2017; 45:7807-7824. [PMID: 28549174 PMCID: PMC5570034 DOI: 10.1093/nar/gkx468] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/09/2017] [Accepted: 05/11/2017] [Indexed: 12/31/2022] Open
Abstract
Chromatin structure affects DNA replication patterns, but the role of specific chromatin modifiers in regulating the replication process is yet unclear. We report that phosphorylation of the human SIRT1 deacetylase on Threonine 530 (T530-pSIRT1) modulates DNA synthesis. T530-pSIRT1 associates with replication origins and inhibits replication from a group of 'dormant' potential replication origins, which initiate replication only when cells are subject to replication stress. Although both active and dormant origins bind T530-pSIRT1, active origins are distinguished from dormant origins by their unique association with an open chromatin mark, histone H3 methylated on lysine 4. SIRT1 phosphorylation also facilitates replication fork elongation. SIRT1 T530 phosphorylation is essential to prevent DNA breakage upon replication stress and cells harboring SIRT1 that cannot be phosphorylated exhibit a high prevalence of extrachromosomal elements, hallmarks of perturbed replication. These observations suggest that SIRT1 phosphorylation modulates the distribution of replication initiation events to insure genomic stability.
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Affiliation(s)
- Koichi Utani
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Haiqing Fu
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sang-Min Jang
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anna B. Marks
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Owen K. Smith
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ya Zhang
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christophe E. Redon
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Noriaki Shimizu
- Graduate School of Biosphere Science, Hiroshima University, Hiroshima 739-8521, Japan
| | - Mirit I. Aladjem
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Aladjem MI, Redon CE. Order from clutter: selective interactions at mammalian replication origins. Nat Rev Genet 2017; 18:101-116. [PMID: 27867195 PMCID: PMC6596300 DOI: 10.1038/nrg.2016.141] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mammalian chromosome duplication progresses in a precise order and is subject to constraints that are often relaxed in developmental disorders and malignancies. Molecular information about the regulation of DNA replication at the chromatin level is lacking because protein complexes that initiate replication seem to bind chromatin indiscriminately. High-throughput sequencing and mathematical modelling have yielded detailed genome-wide replication initiation maps. Combining these maps and models with functional genetic analyses suggests that distinct DNA-protein interactions at subgroups of replication initiation sites (replication origins) modulate the ubiquitous replication machinery and supports an emerging model that delineates how indiscriminate DNA-binding patterns translate into a consistent, organized replication programme.
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Affiliation(s)
- Mirit I Aladjem
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Bethesda, Maryland 20892, USA
| | - Christophe E Redon
- Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Bethesda, Maryland 20892, USA
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Marks AB, Fu H, Aladjem MI. Regulation of Replication Origins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1042:43-59. [PMID: 29357052 DOI: 10.1007/978-981-10-6955-0_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In eukaryotes, genome duplication starts concomitantly at many replication initiation sites termed replication origins. The replication initiation program is spatially and temporally coordinated to ensure accurate, efficient DNA synthesis that duplicates the entire genome while maintaining other chromatin-dependent functions. Unlike in prokaryotes, not all potential replication origins in eukaryotes are needed for complete genome duplication during each cell cycle. Instead, eukaryotic cells vary the use of initiation sites so that only a fraction of potential replication origins initiate replication each cell cycle. Flexibility in origin choice allows each eukaryotic cell type to utilize different initiation sites, corresponding to unique nuclear DNA packaging patterns. These patterns coordinate replication with gene expression and chromatin condensation. Budding yeast replication origins share a consensus sequence that marks potential initiation sites. Metazoan origins, on the other hand, lack a consensus sequence. Rather, they are associated with a collection of structural features, chromatin packaging features, histone modifications, transcription, and DNA-DNA/DNA-protein interactions. These features confer cell type-specific replication and expression and play an essential role in maintaining genomic stability.
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Affiliation(s)
- Anna B Marks
- Developmental Therapeutics Branch, Center for Cancer Research, NCI, NIH, Bethesda, MD, USA
| | - Haiqing Fu
- Developmental Therapeutics Branch, Center for Cancer Research, NCI, NIH, Bethesda, MD, USA
| | - Mirit I Aladjem
- Developmental Therapeutics Branch, Center for Cancer Research, NCI, NIH, Bethesda, MD, USA.
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Making Sense of the Tangle: Insights into Chromatin Folding and Gene Regulation. Genes (Basel) 2016; 7:genes7100071. [PMID: 27669308 PMCID: PMC5083910 DOI: 10.3390/genes7100071] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/10/2016] [Accepted: 09/07/2016] [Indexed: 01/03/2023] Open
Abstract
Proximity ligation assays such as circularized chromosome conformation capture and high-throughput chromosome capture assays have shed light on the structural organization of the interphase genome. Functional topologically associating domains (TADs) that constitute the building blocks of genomic organization are disrupted and reconstructed during the cell cycle. Epigenetic memory, as well as the sequence of chromosomes, regulate TAD reconstitution. Sub-TAD domains that are invariant across cell types have been identified, and contacts between these domains, rather than looping, are speculated to drive chromatin folding. Replication domains are established simultaneously with TADs during the cell cycle and the two correlate well in terms of characteristic features, such as lamin association and histone modifications. CCCTC-binding factor (CTCF) and cohesin cooperate across different cell types to regulate genes and genome organization. CTCF elements that demarcate TAD boundaries are commonly disrupted in cancer and promote oncogene activation. Chromatin looping facilitates interactions between distant promoters and enhancers, and the resulting enhanceosome complex promotes gene expression. Deciphering the chromatin tangle requires comprehensive integrative analyses of DNA- and protein-dependent factors that regulate genomic organization.
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Marks AB, Smith OK, Aladjem MI. Replication origins: determinants or consequences of nuclear organization? Curr Opin Genet Dev 2016; 37:67-75. [PMID: 26845042 PMCID: PMC4914405 DOI: 10.1016/j.gde.2015.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/24/2015] [Accepted: 11/25/2015] [Indexed: 12/20/2022]
Abstract
Chromosome replication, gene expression and chromatin assembly all occur on the same template, necessitating a tight spatial and temporal coordination to maintain genomic stability. The distribution of replication initiation events is responsive to local and global changes in chromatin structure and is affected by transcriptional activity. Concomitantly, replication origin sequences, which determine the locations of replication initiation events, can affect chromatin structure and modulate transcriptional efficiency. The flexibility observed in the replication initiation landscape might help achieve complete and accurate genome duplication while coordinating the DNA replication program with transcription and other nuclear processes in a cell-type specific manner. This review discusses the relationships among replication origin distribution, local and global chromatin structures and concomitant nuclear metabolic processes.
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Affiliation(s)
- Anna B Marks
- Developmental Therapeutics Branch, NCI, NIH, Bethesda, MD, USA
| | - Owen K Smith
- Developmental Therapeutics Branch, NCI, NIH, Bethesda, MD, USA
| | - Mirit I Aladjem
- Developmental Therapeutics Branch, NCI, NIH, Bethesda, MD, USA.
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Müller-Kuller U, Ackermann M, Kolodziej S, Brendel C, Fritsch J, Lachmann N, Kunkel H, Lausen J, Schambach A, Moritz T, Grez M. A minimal ubiquitous chromatin opening element (UCOE) effectively prevents silencing of juxtaposed heterologous promoters by epigenetic remodeling in multipotent and pluripotent stem cells. Nucleic Acids Res 2015; 43:1577-92. [PMID: 25605798 PMCID: PMC4330381 DOI: 10.1093/nar/gkv019] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Epigenetic silencing of transgene expression represents a major obstacle for the efficient genetic modification of multipotent and pluripotent stem cells. We and others have demonstrated that a 1.5 kb methylation-free CpG island from the human HNRPA2B1-CBX3 housekeeping genes (A2UCOE) effectively prevents transgene silencing and variegation in cell lines, multipotent and pluripotent stem cells, and their differentiated progeny. However, the bidirectional promoter activity of this element may disturb expression of neighboring genes. Furthermore, the epigenetic basis underlying the anti-silencing effect of the UCOE on juxtaposed promoters has been only partially explored. In this study we removed the HNRPA2B1 moiety from the A2UCOE and demonstrate efficient anti-silencing properties also for a minimal 0.7 kb element containing merely the CBX3 promoter. This DNA element largely prevents silencing of viral and tissue-specific promoters in multipotent and pluripotent stem cells. The protective activity of CBX3 was associated with reduced promoter CpG-methylation, decreased levels of repressive and increased levels of active histone marks. Moreover, the anti-silencing effect of CBX3 was locally restricted and when linked to tissue-specific promoters did not activate transcription in off target cells. Thus, CBX3 is a highly attractive element for sustained, tissue-specific and copy-number dependent transgene expression in vitro and in vivo.
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Affiliation(s)
- Uta Müller-Kuller
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Mania Ackermann
- RG Reprogramming and Gene Therapy, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany
| | - Stephan Kolodziej
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Christian Brendel
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Jessica Fritsch
- RG Reprogramming and Gene Therapy, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany
| | - Nico Lachmann
- RG Reprogramming and Gene Therapy, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany
| | - Hana Kunkel
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Jörn Lausen
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Axel Schambach
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Division of Pediatric Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas Moritz
- RG Reprogramming and Gene Therapy, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany
| | - Manuel Grez
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
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Erliandri I, Fu H, Nakano M, Kim JH, Miga KH, Liskovykh M, Earnshaw WC, Masumoto H, Kouprina N, Aladjem MI, Larionov V. Replication of alpha-satellite DNA arrays in endogenous human centromeric regions and in human artificial chromosome. Nucleic Acids Res 2014; 42:11502-16. [PMID: 25228468 PMCID: PMC4191410 DOI: 10.1093/nar/gku835] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In human chromosomes, centromeric regions comprise megabase-size arrays of 171 bp alpha-satellite DNA monomers. The large distances spanned by these arrays preclude their replication from external sites and imply that the repetitive monomers contain replication origins. However, replication within these arrays has not previously been profiled and the role of alpha-satellite DNA in initiation of DNA replication has not yet been demonstrated. Here, replication of alpha-satellite DNA in endogenous human centromeric regions and in de novo formed Human Artificial Chromosome (HAC) was analyzed. We showed that alpha-satellite monomers could function as origins of DNA replication and that replication of alphoid arrays organized into centrochromatin occurred earlier than those organized into heterochromatin. The distribution of inter-origin distances within centromeric alphoid arrays was comparable to the distribution of inter-origin distances on randomly selected non-centromeric chromosomal regions. Depletion of CENP-B, a kinetochore protein that binds directly to a 17 bp CENP-B box motif common to alpha-satellite DNA, resulted in enrichment of alpha-satellite sequences for proteins of the ORC complex, suggesting that CENP-B may have a role in regulating the replication of centromeric regions. Mapping of replication initiation sites in the HAC revealed that replication preferentially initiated in transcriptionally active regions.
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Affiliation(s)
- Indri Erliandri
- Developmental Therapeutics Branch, National Cancer Institute, National Institute of Health, Bethesda, MD, 20892, USA
| | - Haiqing Fu
- Developmental Therapeutics Branch, National Cancer Institute, National Institute of Health, Bethesda, MD, 20892, USA
| | - Megumi Nakano
- Laboratory of Cell Engineering, Department of Frontier Research, Kazusa DNA Research Institute, Kisarazu, Chiba, 292-0818, Japan
| | - Jung-Hyun Kim
- Developmental Therapeutics Branch, National Cancer Institute, National Institute of Health, Bethesda, MD, 20892, USA
| | - Karen H Miga
- Center for Biomolecular Science and Engineering, University of California, Santa Cruz, CA, 95064, USA
| | - Mikhail Liskovykh
- Developmental Therapeutics Branch, National Cancer Institute, National Institute of Health, Bethesda, MD, 20892, USA
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, EH9 3JR, UK
| | - Hiroshi Masumoto
- Laboratory of Cell Engineering, Department of Frontier Research, Kazusa DNA Research Institute, Kisarazu, Chiba, 292-0818, Japan
| | - Natalay Kouprina
- Developmental Therapeutics Branch, National Cancer Institute, National Institute of Health, Bethesda, MD, 20892, USA
| | - Mirit I Aladjem
- Developmental Therapeutics Branch, National Cancer Institute, National Institute of Health, Bethesda, MD, 20892, USA
| | - Vladimir Larionov
- Developmental Therapeutics Branch, National Cancer Institute, National Institute of Health, Bethesda, MD, 20892, USA
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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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