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Snedeker J, Davis BEM, Ranjan R, Wooten M, Blundon J, Chen X. Reduced Levels of Lagging Strand Polymerases Shape Stem Cell Chromatin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591383. [PMID: 38746451 PMCID: PMC11092439 DOI: 10.1101/2024.04.26.591383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Stem cells display asymmetric histone inheritance while non-stem progenitor cells exhibit symmetric patterns in the Drosophila male germline lineage. Here, we report that components involved in lagging strand synthesis, such as DNA polymerase α and δ (Polα and Polδ), have significantly reduced levels in stem cells compared to progenitor cells. Compromising Polα genetically induces the replication-coupled histone incorporation pattern in progenitor cells to be indistinguishable from that in stem cells, which can be recapitulated using a Polα inhibitor in a concentration-dependent manner. Furthermore, stem cell-derived chromatin fibers display a higher degree of old histone recycling by the leading strand compared to progenitor cell-derived chromatin fibers. However, upon reducing Polα levels in progenitor cells, the chromatin fibers now display asymmetric old histone recycling just like GSC-derived fibers. The old versus new histone asymmetry is comparable between stem cells and progenitor cells at both S-phase and M-phase. Together, these results indicate that developmentally programmed expression of key DNA replication components is important to shape stem cell chromatin. Furthermore, manipulating one crucial DNA replication component can induce replication-coupled histone dynamics in non-stem cells in a manner similar to that in stem cells.
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Affiliation(s)
- Jonathan Snedeker
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Brendon E. M. Davis
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Rajesh Ranjan
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
- Howard Hughes Medical Institute, Department of Biology, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Baltimore, MD 21218, USA
| | - Matthew Wooten
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
- Current address: Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
| | - Joshua Blundon
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Xin Chen
- Department of Biology, The Johns Hopkins University, Baltimore, MD 21218, USA
- Howard Hughes Medical Institute, Department of Biology, The Johns Hopkins University, 3400 North Charles Street, Baltimore, Baltimore, MD 21218, USA
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2
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Fenstermaker TK, Petruk S, Mazo A. An emerging paradigm in epigenetic marking: coordination of transcription and replication. Transcription 2024; 15:22-37. [PMID: 38378467 DOI: 10.1080/21541264.2024.2316965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/06/2024] [Indexed: 02/22/2024] Open
Abstract
DNA replication and RNA transcription both utilize DNA as a template and therefore need to coordinate their activities. The predominant theory in the field is that in order for the replication fork to proceed, transcription machinery has to be evicted from DNA until replication is complete. If that does not occur, these machineries collide, and these collisions elicit various repair mechanisms which require displacement of one of the enzymes, often RNA polymerase, in order for replication to proceed. This model is also at the heart of the epigenetic bookmarking theory, which implies that displacement of RNA polymerase during replication requires gradual re-building of chromatin structure, which guides recruitment of transcriptional proteins and resumption of transcription. We discuss these theories but also bring to light newer data that suggest that these two processes may not be as detrimental to one another as previously thought. This includes findings suggesting that these processes can occur without fork collapse and that RNA polymerase may only be transiently displaced during DNA replication. We discuss potential mechanisms by which RNA polymerase may be retained at the replication fork and quickly rebind to DNA post-replication. These discoveries are important, not only as new evidence as to how these two processes are able to occur harmoniously but also because they have implications on how transcriptional programs are maintained through DNA replication. To this end, we also discuss the coordination of replication and transcription in light of revising the current epigenetic bookmarking theory of how the active gene status can be transmitted through S phase.
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Affiliation(s)
- Tyler K Fenstermaker
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Svetlana Petruk
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Alexander Mazo
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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Werner M, Hamperl S. A quick restart: RNA polymerase jumping onto post-replicative chromatin. Mol Cell 2024; 84:186-188. [PMID: 38242096 DOI: 10.1016/j.molcel.2023.12.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 01/21/2024]
Abstract
Two recent studies in Molecular Cell1 and Nature2 show that evicted RNA polymerases reassociate rapidly with post-replicative chromatin and proceed into an unusual transcription cycle, bypassing regular controls and creating a temporary window for altered gene expression.
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Affiliation(s)
- Marcel Werner
- Institute of Epigenetics and Stem Cells, Helmholtz Munich, Feodor-Lynen-Strasse 21, 81377 München, Germany
| | - Stephan Hamperl
- Institute of Epigenetics and Stem Cells, Helmholtz Munich, Feodor-Lynen-Strasse 21, 81377 München, Germany.
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Bruno F, Coronel-Guisado C, González-Aguilera C. Collisions of RNA polymerases behind the replication fork promote alternative RNA splicing in newly replicated chromatin. Mol Cell 2024; 84:221-233.e6. [PMID: 38151016 DOI: 10.1016/j.molcel.2023.11.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 08/23/2023] [Accepted: 11/29/2023] [Indexed: 12/29/2023]
Abstract
DNA replication produces a global disorganization of chromatin structure that takes hours to be restored. However, how these chromatin rearrangements affect the regulation of gene expression and the maintenance of cell identity is not clear. Here, we use ChOR-seq and ChrRNA-seq experiments to analyze RNA polymerase II (RNAPII) activity and nascent RNA synthesis during the first hours after chromatin replication in human cells. We observe that transcription elongation is rapidly reactivated in nascent chromatin but that RNAPII abundance and distribution are altered, producing heterogeneous changes in RNA synthesis. Moreover, this first wave of transcription results in RNAPII blockages behind the replication fork, leading to changes in alternative splicing. Altogether, our results deepen our understanding of how transcriptional programs are regulated during cell division and uncover molecular mechanisms that explain why chromatin replication is an important source of gene expression variability.
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Affiliation(s)
- Federica Bruno
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, CSIC, Universidad Pablo de Olavide, 41092, Seville, Spain
| | - Cristóbal Coronel-Guisado
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, CSIC, Universidad Pablo de Olavide, 41092, Seville, Spain
| | - Cristina González-Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla, CSIC, Universidad Pablo de Olavide, 41092, Seville, Spain; Departamento de Biología Celular, Facultad de Biología, Universidad de Sevilla, 41013, Seville, Spain.
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Barrientos-Moreno M, Maya-Miles D, Murillo-Pineda M, Fontalva S, Pérez-Alegre M, Andujar E, Prado F. Transcription and FACT facilitate the restoration of replication-coupled chromatin assembly defects. Sci Rep 2023; 13:11397. [PMID: 37452085 PMCID: PMC10349138 DOI: 10.1038/s41598-023-38280-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023] Open
Abstract
Genome duplication occurs through the coordinated action of DNA replication and nucleosome assembly at replication forks. Defective nucleosome assembly causes DNA lesions by fork breakage that need to be repaired. In addition, it causes a loss of chromatin integrity. These chromatin alterations can be restored, even though the mechanisms are unknown. Here, we show that the process of chromatin restoration can deal with highly severe chromatin defects induced by the absence of the chaperones CAF1 and Rtt106 or a strong reduction in the pool of available histones, and that this process can be followed by analyzing the topoisomer distribution of the 2µ plasmid. Using this assay, we demonstrate that chromatin restoration is slow and independent of checkpoint activation, whereas it requires the action of transcription and the FACT complex. Therefore, cells are able to "repair" not only DNA lesions but also chromatin alterations associated with defective nucleosome assembly.
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Affiliation(s)
- Marta Barrientos-Moreno
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine (CABIMER), CSIC‑University of Seville‑University Pablo de Olavide, Seville, Spain
| | - Douglas Maya-Miles
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine (CABIMER), CSIC‑University of Seville‑University Pablo de Olavide, Seville, Spain
| | - Marina Murillo-Pineda
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine (CABIMER), CSIC‑University of Seville‑University Pablo de Olavide, Seville, Spain
| | - Sara Fontalva
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine (CABIMER), CSIC‑University of Seville‑University Pablo de Olavide, Seville, Spain
| | - Mónica Pérez-Alegre
- Genomic Unit, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), CSIC‑University of Seville‑University Pablo de Olavide, Seville, Spain
| | - Eloísa Andujar
- Genomic Unit, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), CSIC‑University of Seville‑University Pablo de Olavide, Seville, Spain
| | - Félix Prado
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine (CABIMER), CSIC‑University of Seville‑University Pablo de Olavide, Seville, Spain.
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Urban JA, Ranjan R, Chen X. Asymmetric Histone Inheritance: Establishment, Recognition, and Execution. Annu Rev Genet 2022; 56:113-143. [PMID: 35905975 PMCID: PMC10054593 DOI: 10.1146/annurev-genet-072920-125226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The discovery of biased histone inheritance in asymmetrically dividing Drosophila melanogaster male germline stem cells demonstrates one means to produce two distinct daughter cells with identical genetic material. This inspired further studies in different systems, which revealed that this phenomenon may be a widespread mechanism to introduce cellular diversity. While the extent of asymmetric histone inheritance could vary among systems, this phenomenon is proposed to occur in three steps: first, establishment of histone asymmetry between sister chromatids during DNA replication; second, recognition of sister chromatids carrying asymmetric histone information during mitosis; and third, execution of this asymmetry in the resulting daughter cells. By compiling the current knowledge from diverse eukaryotic systems, this review comprehensively details and compares known chromatin factors, mitotic machinery components, and cell cycle regulators that may contribute to each of these three steps. Also discussed are potential mechanisms that introduce and regulate variable histone inheritance modes and how these different modes may contribute to cell fate decisions in multicellular organisms.
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Affiliation(s)
- Jennifer A Urban
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland, USA;
| | - Rajesh Ranjan
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland, USA; .,Howard Hughes Medical Institute, The Johns Hopkins University, Baltimore, Maryland, USA; ,
| | - Xin Chen
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland, USA; .,Howard Hughes Medical Institute, The Johns Hopkins University, Baltimore, Maryland, USA; ,
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Genome-wide mapping of individual replication fork velocities using nanopore sequencing. Nat Commun 2022; 13:3295. [PMID: 35676270 PMCID: PMC9177527 DOI: 10.1038/s41467-022-31012-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/26/2022] [Indexed: 01/27/2023] Open
Abstract
Little is known about replication fork velocity variations along eukaryotic genomes, since reference techniques to determine fork speed either provide no sequence information or suffer from low throughput. Here we present NanoForkSpeed, a nanopore sequencing-based method to map and extract the velocity of individual forks detected as tracks of the thymidine analogue bromodeoxyuridine incorporated during a brief pulse-labelling of asynchronously growing cells. NanoForkSpeed retrieves previous Saccharomyces cerevisiae mean fork speed estimates (≈2 kb/min) in the BT1 strain exhibiting highly efficient bromodeoxyuridine incorporation and wild-type growth, and precisely quantifies speed changes in cells with altered replisome progression or exposed to hydroxyurea. The positioning of >125,000 fork velocities provides a genome-wide map of fork progression based on individual fork rates, showing a uniform fork speed across yeast chromosomes except for a marked slowdown at known pausing sites. Theulot et al. introduce NanoForkSpeed, a nanopore sequencing-based method to map individual replication fork velocities on entire genomes. NFS shows that fork speed is uniform across yeast chromosomes except for a marked slowdown at pausing sites.
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López-Jiménez E, González-Aguilera C. Role of Chromatin Replication in Transcriptional Plasticity, Cell Differentiation and Disease. Genes (Basel) 2022; 13:genes13061002. [PMID: 35741764 PMCID: PMC9222293 DOI: 10.3390/genes13061002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 11/16/2022] Open
Abstract
Chromatin organization is essential to maintain a correct regulation of gene expression and establish cell identity. However, during cell division, the replication of the genetic material produces a global disorganization of chromatin structure. In this paper, we describe the new scientific breakthroughs that have revealed the nature of the post-replicative chromatin and the mechanisms that facilitate its restoration. Moreover, we highlight the implications of these chromatin alterations in gene expression control and their impact on key biological processes, such as cell differentiation, cell reprogramming or human diseases linked to cell proliferation, such as cancer.
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Affiliation(s)
- Elena López-Jiménez
- Faculty of Medicine, National Heart and Lung Institute, Margaret Turner Warwick Centre for Fibrosing Lung Disease, Royal Brompton Campus, Imperial College London, London SW3 6LY, UK;
| | - Cristina González-Aguilera
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, 41092 Seville, Spain
- Departamento de Biología Celular, Facultad de Biología, Universidad de Sevilla, 41013 Seville, Spain
- Correspondence:
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S Phase Duration Is Determined by Local Rate and Global Organization of Replication. BIOLOGY 2022; 11:biology11050718. [PMID: 35625446 PMCID: PMC9139170 DOI: 10.3390/biology11050718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 04/29/2022] [Accepted: 05/03/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary In order for a cell to divide into two cells, it must first copy its DNA. Although the time required for this process tends not to vary much, many examples of the importance of variability have been reported. In this review, we discuss the methods used to study this question, present some of the examples of variation, and attempt to explain the factors that determine the time required in simple terms. We will show that the overall time depends on the rate of DNA replication within a region, and on the temporal organization of the regions relative to each other. Abstract The duration of the cell cycle has been extensively studied and a wide degree of variability exists between cells, tissues and organisms. However, the duration of S phase has often been neglected, due to the false assumption that S phase duration is relatively constant. In this paper, we describe the methodologies to measure S phase duration, summarize the existing knowledge about its variability and discuss the key factors that control it. The local rate of replication (LRR), which is a combination of fork rate (FR) and inter-origin distance (IOD), has a limited influence on S phase duration, partially due to the compensation between FR and IOD. On the other hand, the organization of the replication program, specifically the amount of replication domains that fire simultaneously and the degree of overlap between the firing of distinct replication timing domains, is the main determinant of S phase duration. We use these principles to explain the variation in S phase length in different tissues and conditions.
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