1
|
Serra-Cardona A, Hua X, McNutt SW, Zhou H, Toda T, Jia S, Chu F, Zhang Z. The PCNA-Pol δ complex couples lagging strand DNA synthesis to parental histone transfer for epigenetic inheritance. SCIENCE ADVANCES 2024; 10:eadn5175. [PMID: 38838138 PMCID: PMC11152121 DOI: 10.1126/sciadv.adn5175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 05/01/2024] [Indexed: 06/07/2024]
Abstract
Inheritance of epigenetic information is critical for maintaining cell identity. The transfer of parental histone H3-H4 tetramers, the primary carrier of epigenetic modifications on histone proteins, represents a crucial yet poorly understood step in the inheritance of epigenetic information. Here, we show the lagging strand DNA polymerase, Pol δ, interacts directly with H3-H4 and that the interaction between Pol δ and the sliding clamp PCNA regulates parental histone transfer to lagging strands, most likely independent of their roles in DNA synthesis. When combined, mutations at Pol δ and Mcm2 that compromise parental histone transfer result in a greater reduction in nucleosome occupancy at nascent chromatin than mutations in either alone. Last, PCNA contributes to nucleosome positioning on nascent chromatin. On the basis of these results, we suggest that the PCNA-Pol δ complex couples lagging strand DNA synthesis to parental H3-H4 transfer, facilitating epigenetic inheritance.
Collapse
Affiliation(s)
- Albert Serra-Cardona
- Institute for Cancer Genetics, Department of Pediatrics and Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10019, USA
| | - Xu Hua
- Institute for Cancer Genetics, Department of Pediatrics and Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10019, USA
| | - Seth W. McNutt
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Hui Zhou
- Institute for Cancer Genetics, Department of Pediatrics and Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10019, USA
| | - Takenori Toda
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Feixia Chu
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Zhiguo Zhang
- Institute for Cancer Genetics, Department of Pediatrics and Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10019, USA
| |
Collapse
|
2
|
Karri S, Yang Y, Zhou J, Dickinson Q, Jia J, Huang Y, Wang Z, Gan H, Yu C. Defective transfer of parental histone decreases frequency of homologous recombination by increasing free histone pools in budding yeast. Nucleic Acids Res 2024; 52:5138-5151. [PMID: 38554108 PMCID: PMC11109958 DOI: 10.1093/nar/gkae205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/27/2024] [Accepted: 03/08/2024] [Indexed: 04/01/2024] Open
Abstract
Recycling of parental histones is an important step in epigenetic inheritance. During DNA replication, DNA polymerase epsilon subunit DPB3/DPB4 and DNA replication helicase subunit MCM2 are involved in the transfer of parental histones to the leading and lagging strands, respectively. Single Dpb3 deletion (dpb3Δ) or Mcm2 mutation (mcm2-3A), which each disrupts one parental histone transfer pathway, leads to the other's predominance. However, the biological impact of the two histone transfer pathways on chromatin structure and DNA repair remains elusive. In this study, we used budding yeast Saccharomyces cerevisiae to determine the genetic and epigenetic outcomes from disruption of parental histone H3-H4 tetramer transfer. We found that a dpb3Δ mcm2-3A double mutant did not exhibit the asymmetric parental histone patterns caused by a single dpb3Δ or mcm2-3A mutation, suggesting that the processes by which parental histones are transferred to the leading and lagging strands are independent. Surprisingly, the frequency of homologous recombination was significantly lower in dpb3Δ, mcm2-3A and dpb3Δ mcm2-3A mutants, likely due to the elevated levels of free histones detected in the mutant cells. Together, these findings indicate that proper transfer of parental histones during DNA replication is essential for maintaining chromatin structure and that lower homologous recombination activity due to parental histone transfer defects is detrimental to cells.
Collapse
Affiliation(s)
- Srinivasu Karri
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Yi Yang
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Jiaqi Zhou
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Quinn Dickinson
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Jing Jia
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Yuxin Huang
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Zhiquan Wang
- Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Haiyun Gan
- CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics and Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Chuanhe Yu
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| |
Collapse
|
3
|
Ouasti F, Audin M, Fréon K, Quivy JP, Tachekort M, Cesard E, Thureau A, Ropars V, Fernández Varela P, Moal G, Soumana-Amadou I, Uryga A, Legrand P, Andreani J, Guerois R, Almouzni G, Lambert S, Ochsenbein F. Disordered regions and folded modules in CAF-1 promote histone deposition in Schizosaccharomyces pombe. eLife 2024; 12:RP91461. [PMID: 38376141 PMCID: PMC10942606 DOI: 10.7554/elife.91461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024] Open
Abstract
Genome and epigenome integrity in eukaryotes depends on the proper coupling of histone deposition with DNA synthesis. This process relies on the evolutionary conserved histone chaperone CAF-1 for which the links between structure and functions are still a puzzle. While studies of the Saccharomyces cerevisiae CAF-1 complex enabled to propose a model for the histone deposition mechanism, we still lack a framework to demonstrate its generality and in particular, how its interaction with the polymerase accessory factor PCNA is operating. Here, we reconstituted a complete SpCAF-1 from fission yeast. We characterized its dynamic structure using NMR, SAXS and molecular modeling together with in vitro and in vivo functional studies on rationally designed interaction mutants. Importantly, we identify the unfolded nature of the acidic domain which folds up when binding to histones. We also show how the long KER helix mediates DNA binding and stimulates SpCAF-1 association with PCNA. Our study highlights how the organization of CAF-1 comprising both disordered regions and folded modules enables the dynamics of multiple interactions to promote synthesis-coupled histone deposition essential for its DNA replication, heterochromatin maintenance, and genome stability functions.
Collapse
Affiliation(s)
- Fouad Ouasti
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| | - Maxime Audin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| | - Karine Fréon
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Université Paris-Saclay, Equipe labellisée Ligue contre le CancerOrsayFrance
| | - Jean-Pierre Quivy
- Institut Curie, PSL Research University, CNRS, Sorbonne Université,CNRS UMR3664, Nuclear Dynamics Unit, Équipe Labellisée Ligue contre le CancerParisFrance
| | - Mehdi Tachekort
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| | - Elizabeth Cesard
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| | - Aurélien Thureau
- Synchrotron SOLEIL, HelioBio group, l'Orme des MerisiersSaint-AubinFrance
| | - Virginie Ropars
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| | - Paloma Fernández Varela
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| | - Gwenaelle Moal
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| | - Ibrahim Soumana-Amadou
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Université Paris-Saclay, Equipe labellisée Ligue contre le CancerOrsayFrance
| | - Aleksandra Uryga
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Université Paris-Saclay, Equipe labellisée Ligue contre le CancerOrsayFrance
| | - Pierre Legrand
- Synchrotron SOLEIL, HelioBio group, l'Orme des MerisiersSaint-AubinFrance
| | - Jessica Andreani
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| | - Raphaël Guerois
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| | - Geneviève Almouzni
- Institut Curie, PSL Research University, CNRS, Sorbonne Université,CNRS UMR3664, Nuclear Dynamics Unit, Équipe Labellisée Ligue contre le CancerParisFrance
| | - Sarah Lambert
- Institut Curie, PSL Research University, CNRS UMR 3348, INSERM U1278, Université Paris-Saclay, Equipe labellisée Ligue contre le CancerOrsayFrance
| | - Francoise Ochsenbein
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Institute JoliotGif-sur-YvetteFrance
| |
Collapse
|
4
|
Yuan AH, Moazed D. Minimal requirements for the epigenetic inheritance of engineered silent chromatin domains. Proc Natl Acad Sci U S A 2024; 121:e2318455121. [PMID: 38198529 PMCID: PMC10801849 DOI: 10.1073/pnas.2318455121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Accepted: 12/06/2023] [Indexed: 01/12/2024] Open
Abstract
Mechanisms enabling genetically identical cells to differentially regulate gene expression are complex and central to organismal development and evolution. While gene silencing pathways involving DNA sequence-specific recruitment of histone-modifying enzymes are prevalent in nature, examples of sequence-independent heritable gene silencing are scarce. Studies of the fission yeast Schizosaccharomyces pombe indicate that sequence-independent propagation of heterochromatin can occur but requires numerous multisubunit protein complexes and their diverse activities. Such complexity has so far precluded a coherent articulation of the minimal requirements for heritable gene silencing by conventional in vitro reconstitution approaches. Here, we take an unconventional approach to defining these requirements by engineering sequence-independent silent chromatin inheritance in budding yeast Saccharomyces cerevisiae cells. The mechanism conferring memory upon these cells is remarkably simple and requires only two proteins, one that recognizes histone H3 lysine 9 methylation (H3K9me) and catalyzes the deacetylation of histone H4 lysine 16 (H4K16), and another that recognizes deacetylated H4K16 and catalyzes H3K9me. Together, these bilingual "read-write" proteins form an interdependent positive feedback loop that is sufficient for the transmission of DNA sequence-independent silent information over multiple generations.
Collapse
Affiliation(s)
- Andy H. Yuan
- HHMI, Harvard Medical School, Boston, MA02115
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| | - Danesh Moazed
- HHMI, Harvard Medical School, Boston, MA02115
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA02115
| |
Collapse
|
5
|
Shaban K, Dolson A, Fisher A, Lessard E, Sauty SM, Yankulov K. TOF1 and RRM3 reveal a link between gene silencing and the pausing of replication forks. Curr Genet 2023; 69:235-249. [PMID: 37347284 DOI: 10.1007/s00294-023-01273-3] [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: 02/16/2023] [Revised: 06/01/2023] [Accepted: 06/14/2023] [Indexed: 06/23/2023]
Abstract
Eukaryotic DNA replication is accompanied by the disassembly and reassembly of nucleosomes and the transmission of epigenetic marks to the newly assembled chromatids. Several histone chaperones, including CAF-1 and Asf1p, are central to these processes. On the other hand, replication forks pause at numerous positions throughout the genome, but it is not known if and how this pausing affects the reassembly and maintenance of chromatin structures. Here, we applied drug-free gene silencing assays to analyze the genetic interactions between CAC1, ASF1, and two genes that regulate the stability of the paused replisome (TOF1) and the resumption of elongation (RRM3). Our results show that TOF1 and RRM3 differentially interact with CAF-1 and ASF1 and that the deletions of TOF1 and RRM3 lead to reduced silencing and increased frequency of epigenetic conversions at three loci in the genome of S. cerevisiae. Our study adds details to the known activities of CAF-1 and Asf1p and suggests that the pausing of the replication fork can lead to epigenetic instability.
Collapse
Affiliation(s)
- Kholoud Shaban
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G2W1, Canada
| | - Andrew Dolson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G2W1, Canada
| | - Ashley Fisher
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G2W1, Canada
| | - Emma Lessard
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G2W1, Canada
| | - Safia Mahabub Sauty
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G2W1, Canada
| | - Krassimir Yankulov
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G2W1, Canada.
| |
Collapse
|
6
|
Sauty SM, Yankulov K. Analyses of POL30 (PCNA) reveal positional effects in transient repression or bi-modal active/silent state at the sub-telomeres of S. cerevisiae. Epigenetics Chromatin 2023; 16:40. [PMID: 37858268 PMCID: PMC10585736 DOI: 10.1186/s13072-023-00513-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 10/06/2023] [Indexed: 10/21/2023] Open
Abstract
BACKGROUND Classical studies on position effect variegation in Drosophila have demonstrated the existence of bi-modal Active/Silent state of the genes juxtaposed to heterochromatin. Later studies with irreversible methods for the detection of gene repression have revealed a similar phenomenon at the telomeres of Saccharomyces cerevisiae and other species. In this study, we used dual reporter constructs and a combination of reversible and non-reversible methods to present evidence for the different roles of PCNA and histone chaperones in the stability and the propagation of repressed states at the sub-telomeres of S. cerevisiae. RESULTS We show position dependent transient repression or bi-modal expression of reporter genes at the VIIL sub-telomere. We also show that mutations in the replicative clamp POL30 (PCNA) or the deletion of the histone chaperone CAF1 or the RRM3 helicase lead to transient de-repression, while the deletion of the histone chaperone ASF1 causes a shift from transient de-repression to a bi-modal state of repression. We analyze the physical interaction of CAF1 and RRM3 with PCNA and discuss the implications of these findings for our understanding of the stability and transmission of the epigenetic state of the genes. CONCLUSIONS There are distinct modes of gene silencing, bi-modal and transient, at the sub-telomeres of S. cerevisiae. We characterise the roles of CAF1, RRM3 and ASF1 in these modes of gene repression. We suggest that the interpretations of past and future studies should consider the existence of the dissimilar states of gene silencing.
Collapse
Affiliation(s)
- Safia Mahabub Sauty
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G2W1, Canada
| | - Krassimir Yankulov
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G2W1, Canada.
| |
Collapse
|
7
|
Bondra ER, Rine J. Context-dependent function of the transcriptional regulator Rap1 in gene silencing and activation in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2023; 120:e2304343120. [PMID: 37769255 PMCID: PMC10556627 DOI: 10.1073/pnas.2304343120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 08/04/2023] [Indexed: 09/30/2023] Open
Abstract
In Saccharomyces cerevisiae, heterochromatin is formed through interactions between site-specific DNA-binding factors, including the transcriptional activator Repressor Activator Protein (Rap1), and Sir proteins. Despite an understanding of the establishment and maintenance of Sir-silenced chromatin, the mechanism of gene silencing by Sir proteins has remained a mystery. Utilizing high-resolution chromatin immunoprecipitation, we found that Rap1, the native activator of the bidirectional HMLα promoter, bound its recognition sequence in silenced chromatin, and its binding was enhanced by the presence of Sir proteins. In contrast to prior results, various components of transcription machinery were not able to access HMLα in the silenced state. These findings disproved the long-standing model of indiscriminate steric occlusion by Sir proteins and led to investigation of the role of the transcriptional activator Rap1 in Sir-silenced chromatin. Using a highly sensitive assay that monitors loss-of-silencing events, we identified a role for promoter-bound Rap1 in the maintenance of silent chromatin through interactions with the Sir complex. We also found that promoter-bound Rap1 activated HMLα when in an expressed state, and aided in the transition from transcription initiation to elongation. Highlighting the importance of epigenetic context in transcription factor function, these results point toward a model in which the duality of Rap1 function was mediated by local chromatin environment rather than binding-site availability.
Collapse
Affiliation(s)
- Eliana R. Bondra
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Jasper Rine
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| |
Collapse
|
8
|
Ghaddar N, Luciano P, Géli V, Corda Y. Chromatin assembly factor-1 preserves genome stability in ctf4Δ cells by promoting sister chromatid cohesion. Cell Stress 2023; 7:69-89. [PMID: 37662646 PMCID: PMC10468696 DOI: 10.15698/cst2023.09.289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 09/05/2023] Open
Abstract
Chromatin assembly and the establishment of sister chromatid cohesion are intimately connected to the progression of DNA replication forks. Here we examined the genetic interaction between the heterotrimeric chromatin assembly factor-1 (CAF-1), a central component of chromatin assembly during replication, and the core replisome component Ctf4. We find that CAF-1 deficient cells as well as cells affected in newly-synthesized H3-H4 histones deposition during DNA replication exhibit a severe negative growth with ctf4Δ mutant. We dissected the role of CAF-1 in the maintenance of genome stability in ctf4Δ yeast cells. In the absence of CTF4, CAF-1 is essential for viability in cells experiencing replication problems, in cells lacking functional S-phase checkpoint or functional spindle checkpoint, and in cells lacking DNA repair pathways involving homologous recombination. We present evidence that CAF-1 affects cohesin association to chromatin in a DNA-damage-dependent manner and is essential to maintain cohesion in the absence of CTF4. We also show that Eco1-catalyzed Smc3 acetylation is reduced in absence of CAF-1. Furthermore, we describe genetic interactions between CAF-1 and essential genes involved in cohesin loading, cohesin stabilization, and cohesin component indicating that CAF-1 is crucial for viability when sister chromatid cohesion is affected. Finally, our data indicate that the CAF-1-dependent pathway required for cohesion is functionally distinct from the Rtt101-Mms1-Mms22 pathway which functions in replicated chromatin assembly. Collectively, our results suggest that the deposition by CAF-1 of newly-synthesized H3-H4 histones during DNA replication creates a chromatin environment that favors sister chromatid cohesion and maintains genome integrity.
Collapse
Affiliation(s)
- Nagham Ghaddar
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix Marseille Univ, Institut Paoli-Calmettes, Marseille, France. Ligue Nationale Contre le Cancer (Labeled Equip)
| | - Pierre Luciano
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix Marseille Univ, Institut Paoli-Calmettes, Marseille, France. Ligue Nationale Contre le Cancer (Labeled Equip)
| | - Vincent Géli
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix Marseille Univ, Institut Paoli-Calmettes, Marseille, France. Ligue Nationale Contre le Cancer (Labeled Equip)
| | - Yves Corda
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix Marseille Univ, Institut Paoli-Calmettes, Marseille, France. Ligue Nationale Contre le Cancer (Labeled Equip)
| |
Collapse
|
9
|
CAI TIANYING, BAI JUNJIE, TAN PENG, HUANG ZHIWEI, LIU CHEN, WU ZIMING, CHENG YONGLANG, LI TONGXI, CHEN YIFAN, RUAN JIAN, GAO LIN, DU YICHAO, FU WENGUANG. Zyxin promotes hepatocellular carcinoma progression via the activation of AKT/mTOR signaling pathway. Oncol Res 2023; 31:805-817. [PMID: 37547758 PMCID: PMC10398406 DOI: 10.32604/or.2023.029549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 05/17/2023] [Indexed: 08/08/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is a common malignancy that is driven by multiple genes and pathways. The aim of this study was to investigate the role and specific mechanism of the actin-interacting protein zyxin (ZYX) in HCC. We found that the expression of ZYX was significantly higher in HCC tissues compared to that in normal liver tissues. In addition, overexpression of ZYX in hepatoma cell lines (PLC/PRF/5, HCCLM3) enhanced their proliferation, migration and invasion, whereas ZYX knockdown had the opposite effects (SK HEP-1, Huh-7). Furthermore, the change in the expression levels of ZYX also altered that of proteins related to cell cycle, migration and invasion. Similar results were obtained with xenograft models. The AKT/mTOR signaling pathway is one of the key mediators of cancer development. While ZYX overexpression upregulated the levels of phosphorylated AKT/mTOR proteins, its knockdown had the opposite effect. In addition, the AKT inhibitor MK2206 neutralized the pro-oncogenic effects of ZYX on the HCC cells, whereas the AKT activator SC79 restored the proliferation, migration and invasion of HCC cells with ZYX knockdown. Taken together, ZYX promotes the malignant progression of HCC by activating AKT/mTOR signaling pathway, and is a potential therapeutic target in HCC.
Collapse
Affiliation(s)
- TIANYING CAI
- Department of Hepatobiliary Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
- Biobank, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - JUNJIE BAI
- Department of Hepatobiliary Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - PENG TAN
- Academician (Expert) Workstation of Sichuan Province, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - ZHIWEI HUANG
- Department of Hepatobiliary Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - CHEN LIU
- Department of Hepatobiliary Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - ZIMING WU
- Department of Hepatobiliary Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - YONGLANG CHENG
- Department of Hepatobiliary Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - TONGXI LI
- Department of Hepatobiliary Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - YIFAN CHEN
- Department of Hepatobiliary Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - JIAN RUAN
- Department of Medical Oncology, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310000, China
| | - LIN GAO
- Department of Health Management, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - YICHAO DU
- Academician (Expert) Workstation of Sichuan Province, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - WENGUANG FU
- Department of Hepatobiliary Surgery, Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
- Academician (Expert) Workstation of Sichuan Province, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| |
Collapse
|
10
|
Bondra ER, Rine J. Context dependent function of the transcriptional regulator Rap1 in gene silencing and activation in Saccharomyces cerevisiae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.08.539937. [PMID: 37214837 PMCID: PMC10197613 DOI: 10.1101/2023.05.08.539937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In Saccharomyces cerevisiae, heterochromatin is formed through interactions between site-specific DNA-binding factors, including the transcriptional activator Rap1, and Sir proteins. Despite a vast understanding of the establishment and maintenance of Sir-silenced chromatin, the mechanism of gene silencing by Sir proteins has remained a mystery. Utilizing high resolution chromatin immunoprecipitation, we found that Rap1, the native activator of the bi-directional HML α promoter, bound its recognition sequence in silenced chromatin and its binding was enhanced by the presence of Sir proteins. In contrast to prior results, various components of transcription machinery were not able to access HML α in the silenced state. These findings disproved the long-standing model of indiscriminate steric occlusion by Sir proteins and led to investigation of the transcriptional activator Rap1 in Sir-silenced chromatin. Using a highly sensitive assay that monitors loss-of-silencing events, we identified a novel role for promoter-bound Rap1 in the maintenance of silent chromatin through interactions with the Sir complex. We also found that promoter-bound Rap1 activated HML α when in an expressed state, and aided in the transition from transcription initiation to elongation. Highlighting the importance of epigenetic context in transcription factor function, these results point toward a model in which the duality of Rap1 function was mediated by local chromatin environment rather than binding-site availability. Significance Statement The coarse partitioning of the genome into regions of active euchromatin and repressed heterochromatin is an important, and conserved, level gene expression regulation in eukaryotes. Repressor Activator Protein (Rap1) is a transcription factor that promotes the activation of genes when recruited to promoters, and aids in the establishment of heterochromatin through interactions with silencer elements. Here, we investigate the role of Rap1 when bound to a promoter in silent chromatin and dissect the context-specific epigenetic cues that regulate the dual properties of this transcription factor. Together, our data highlight the importance of protein-protein interactions and local chromatin state on transcription factor function.
Collapse
Affiliation(s)
- Eliana R Bondra
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, United States
| | - Jasper Rine
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, United States
| |
Collapse
|
11
|
Choudhary K, Kupiec M. The cohesin complex of yeasts: sister chromatid cohesion and beyond. FEMS Microbiol Rev 2023; 47:6825453. [PMID: 36370456 DOI: 10.1093/femsre/fuac045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022] Open
Abstract
Each time a cell divides, it needs to duplicate the genome and then separate the two copies. In eukaryotes, which usually have more than one linear chromosome, this entails tethering the two newly replicated DNA molecules, a phenomenon known as sister chromatid cohesion (SCC). Cohesion ensures proper chromosome segregation to separate poles during mitosis. SCC is achieved by the presence of the cohesin complex. Besides its canonical function, cohesin is essential for chromosome organization and DNA damage repair. Surprisingly, yeast cohesin is loaded in G1 before DNA replication starts but only acquires its binding activity during DNA replication. Work in microorganisms, such as Saccharomyces cerevisiae and Schizosaccharomyces pombe has greatly contributed to the understanding of cohesin composition and functions. In the last few years, much progress has been made in elucidating the role of cohesin in chromosome organization and compaction. Here, we discuss the different functions of cohesin to ensure faithful chromosome segregation and genome stability during the mitotic cell division in yeast. We describe what is known about its composition and how DNA replication is coupled with SCC establishment. We also discuss current models for the role of cohesin in chromatin loop extrusion and delineate unanswered questions about the activity of this important, conserved complex.
Collapse
Affiliation(s)
- Karan Choudhary
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Martin Kupiec
- The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Ramat Aviv 69978, Israel
| |
Collapse
|
12
|
Effects of Defective Unloading and Recycling of PCNA Revealed by the Analysis of ELG1 Mutants. Int J Mol Sci 2023; 24:ijms24021568. [PMID: 36675081 PMCID: PMC9863317 DOI: 10.3390/ijms24021568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
Timely and complete replication of the genome is essential for life. The PCNA ring plays an essential role in DNA replication and repair by contributing to the processivity of DNA polymerases and by recruiting proteins that act in DNA replication-associated processes. The ELG1 gene encodes a protein that works, together with the Rfc2-5 subunits (shared by the replication factor C complex), to unload PCNA from chromatin. While ELG1 is not essential for life, deletion of the gene has strong consequences for the stability of the genome, and elg1 mutants exhibit sensitivity to DNA damaging agents, defects in genomic silencing, high mutation rates, and other striking phenotypes. Here, we sought to understand whether all the roles attributed to Elg1 in genome stability maintenance are due to its effects on PCNA unloading, or whether they are due to additional functions of the protein. By using a battery of mutants that affect PCNA accumulation at various degrees, we show that all the phenotypes measured correlate with the amount of PCNA left at the chromatin. Our results thus demonstrate the importance of Elg1 and of PCNA unloading in promoting proper chromatin structure and in maintaining a stable genome.
Collapse
|
13
|
Karri S, Yang Y, Zhou J, Dickson Q, Wang Z, Gan H, Yu C. Defective transfer of parental histone decreases frequency of homologous recombination in budding yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.10.523501. [PMID: 36711718 PMCID: PMC9882084 DOI: 10.1101/2023.01.10.523501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Recycling of parental histones is an important step in epigenetic inheritance. During DNA replication, DNA polymerase epsilon subunit DPB3/DPB4 and DNA replication helicase subunit MCM2 are involved in the transfer of parental histones to the leading and lagging DNA strands, respectively. Single Dpb3 deletion ( dpb3Δ ) or Mcm2 mutation ( mcm2-3A ), which each disrupt one parental histone transfer pathway, leads to the other's predominance. However, the impact of the two histone transfer pathways on chromatin structure and DNA repair remains elusive. In this study, we used budding yeast Saccharomyces cerevisiae to determine the genetic and epigenetic outcomes from disruption of parental histone H3-H4 tetramer transfer. We found that a dpb3Δ / mcm2-3A double mutant did not exhibit the single dpb3Δ and mcm2-3A mutants' asymmetric parental histone patterns, suggesting that the processes by which parental histones are transferred to the leading and lagging strands are independent. Surprisingly, the frequency of homologous recombination was significantly lower in dpb3Δ, mcm2-3A , and dpb3Δ / mcm2-3A mutants relative to the wild-type strain, likely due to the elevated levels of free histones detected in the mutant cells. Together, these findings indicate that proper transfer of parental histones to the leading and lagging strands during DNA replication is essential for maintaining chromatin structure and that high levels of free histones due to parental histone transfer defects are detrimental to cells.
Collapse
|
14
|
Li X, Wang L, Liu X, Zheng Z, Kong D. Cellular regulation and stability of DNA replication forks in eukaryotic cells. DNA Repair (Amst) 2022; 120:103418. [DOI: 10.1016/j.dnarep.2022.103418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/03/2022] [Accepted: 10/07/2022] [Indexed: 11/03/2022]
|
15
|
Park SH, Kim Y, Ra JS, Wie MW, Kang MS, Kang S, Myung K, Lee KY. Timely termination of repair DNA synthesis by ATAD5 is important in oxidative DNA damage-induced single-strand break repair. Nucleic Acids Res 2021; 49:11746-11764. [PMID: 34718749 PMCID: PMC8599757 DOI: 10.1093/nar/gkab999] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 10/06/2021] [Accepted: 10/12/2021] [Indexed: 12/15/2022] Open
Abstract
Reactive oxygen species (ROS) generate oxidized bases and single-strand breaks (SSBs), which are fixed by base excision repair (BER) and SSB repair (SSBR), respectively. Although excision and repair of damaged bases have been extensively studied, the function of the sliding clamp, proliferating cell nuclear antigen (PCNA), including loading/unloading, remains unclear. We report that, in addition to PCNA loading by replication factor complex C (RFC), timely PCNA unloading by the ATPase family AAA domain-containing protein 5 (ATAD5)-RFC-like complex is important for the repair of ROS-induced SSBs. We found that PCNA was loaded at hydrogen peroxide (H2O2)-generated direct SSBs after the 3'-terminus was converted to the hydroxyl moiety by end-processing enzymes. However, PCNA loading rarely occurred during BER of oxidized or alkylated bases. ATAD5-depleted cells were sensitive to acute H2O2 treatment but not methyl methanesulfonate treatment. Unexpectedly, when PCNA remained on DNA as a result of ATAD5 depletion, H2O2-induced repair DNA synthesis increased in cancerous and normal cells. Based on higher H2O2-induced DNA breakage and SSBR protein enrichment by ATAD5 depletion, we propose that extended repair DNA synthesis increases the likelihood of DNA polymerase stalling, shown by increased PCNA monoubiquitination, and consequently, harmful nick structures are more frequent.
Collapse
Affiliation(s)
- Su Hyung Park
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Youyoung Kim
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea.,Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jae Sun Ra
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Min Woo Wie
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea.,Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Mi-Sun Kang
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Sukhyun Kang
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea.,Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Kyoo-Young Lee
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, Republic of Korea
| |
Collapse
|
16
|
PCNA Loaders and Unloaders-One Ring That Rules Them All. Genes (Basel) 2021; 12:genes12111812. [PMID: 34828416 PMCID: PMC8618651 DOI: 10.3390/genes12111812] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 12/23/2022] Open
Abstract
During each cell duplication, the entirety of the genomic DNA in every cell must be accurately and quickly copied. Given the short time available for the chore, the requirement of many proteins, and the daunting amount of DNA present, DNA replication poses a serious challenge to the cell. A high level of coordination between polymerases and other DNA and chromatin-interacting proteins is vital to complete this task. One of the most important proteins for maintaining such coordination is PCNA. PCNA is a multitasking protein that forms a homotrimeric ring that encircles the DNA. It serves as a processivity factor for DNA polymerases and acts as a landing platform for different proteins interacting with DNA and chromatin. Therefore, PCNA is a signaling hub that influences the rate and accuracy of DNA replication, regulates DNA damage repair, controls chromatin formation during the replication, and the proper segregation of the sister chromatids. With so many essential roles, PCNA recruitment and turnover on the chromatin is of utmost importance. Three different, conserved protein complexes are in charge of loading/unloading PCNA onto DNA. Replication factor C (RFC) is the canonical complex in charge of loading PCNA during the S-phase. The Ctf18 and Elg1 (ATAD5 in mammalian) proteins form complexes similar to RFC, with particular functions in the cell’s nucleus. Here we summarize our current knowledge about the roles of these important factors in yeast and mammals.
Collapse
|
17
|
Huang JH, Liao YR, Lin TC, Tsai CH, Lai WY, Chou YK, Leu JY, Tsai HK, Kao CF. iTARGEX analysis of yeast deletome reveals novel regulators of transcriptional buffering in S phase and protein turnover. Nucleic Acids Res 2021; 49:7318-7329. [PMID: 34197604 PMCID: PMC8287957 DOI: 10.1093/nar/gkab555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/12/2021] [Accepted: 06/29/2021] [Indexed: 11/24/2022] Open
Abstract
Integrating omics data with quantification of biological traits provides unparalleled opportunities for discovery of genetic regulators by in silico inference. However, current approaches to analyze genetic-perturbation screens are limited by their reliance on annotation libraries for prioritization of hits and subsequent targeted experimentation. Here, we present iTARGEX (identification of Trait-Associated Regulatory Genes via mixture regression using EXpectation maximization), an association framework with no requirement of a priori knowledge of gene function. After creating this tool, we used it to test associations between gene expression profiles and two biological traits in single-gene deletion budding yeast mutants, including transcription homeostasis during S phase and global protein turnover. For each trait, we discovered novel regulators without prior functional annotations. The functional effects of the novel candidates were then validated experimentally, providing solid evidence for their roles in the respective traits. Hence, we conclude that iTARGEX can reliably identify novel factors involved in given biological traits. As such, it is capable of converting genome-wide observations into causal gene function predictions. Further application of iTARGEX in other contexts is expected to facilitate the discovery of new regulators and provide observations for novel mechanistic hypotheses regarding different biological traits and phenotypes.
Collapse
Affiliation(s)
- Jia-Hsin Huang
- Institute of Information Science, Academia Sinica, Taipei 115, Taiwan
| | - You-Rou Liao
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| | - Tzu-Chieh Lin
- Institute of Information Science, Academia Sinica, Taipei 115, Taiwan
| | - Cheng-Hung Tsai
- Institute of Information Science, Academia Sinica, Taipei 115, Taiwan
| | - Wei-Yun Lai
- Institute of Information Science, Academia Sinica, Taipei 115, Taiwan
| | - Yang-Kai Chou
- Institute of Information Science, Academia Sinica, Taipei 115, Taiwan
| | - Jun-Yi Leu
- Institute of Molecular Biology, Academia Sinica, Taipei 115, Taiwan
| | - Huai-Kuang Tsai
- Institute of Information Science, Academia Sinica, Taipei 115, Taiwan
| | - Cheng-Fu Kao
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan
| |
Collapse
|
18
|
Thakar T, Moldovan GL. The emerging determinants of replication fork stability. Nucleic Acids Res 2021; 49:7224-7238. [PMID: 33978751 PMCID: PMC8287955 DOI: 10.1093/nar/gkab344] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 04/18/2021] [Accepted: 04/20/2021] [Indexed: 12/21/2022] Open
Abstract
A universal response to replication stress is replication fork reversal, where the nascent complementary DNA strands are annealed to form a protective four-way junction allowing forks to avert DNA damage while replication stress is resolved. However, reversed forks are in turn susceptible to nucleolytic digestion of the regressed nascent DNA arms and rely on dedicated mechanisms to protect their integrity. The most well studied fork protection mechanism involves the BRCA pathway and its ability to catalyze RAD51 nucleofilament formation on the reversed arms of stalled replication forks. Importantly, the inability to prevent the degradation of reversed forks has emerged as a hallmark of BRCA deficiency and underlies genome instability and chemosensitivity in BRCA-deficient cells. In the past decade, multiple factors underlying fork stability have been discovered. These factors either cooperate with the BRCA pathway, operate independently from it to augment fork stability in its absence, or act as enablers of fork degradation. In this review, we examine these novel determinants of fork stability, explore the emergent conceptual underpinnings underlying fork protection, as well as the impact of fork protection on cellular viability and cancer therapy.
Collapse
Affiliation(s)
- Tanay Thakar
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| |
Collapse
|
19
|
Subramanian S, Gorday K, Marcus K, Orellana MR, Ren P, Luo XR, O'Donnell ME, Kuriyan J. Allosteric communication in DNA polymerase clamp loaders relies on a critical hydrogen-bonded junction. eLife 2021; 10:e66181. [PMID: 33847559 PMCID: PMC8121543 DOI: 10.7554/elife.66181] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/03/2021] [Indexed: 02/06/2023] Open
Abstract
Clamp loaders are AAA+ ATPases that load sliding clamps onto DNA. We mapped the mutational sensitivity of the T4 bacteriophage sliding clamp and clamp loader by deep mutagenesis, and found that residues not involved in catalysis or binding display remarkable tolerance to mutation. An exception is a glutamine residue in the AAA+ module (Gln 118) that is not located at a catalytic or interfacial site. Gln 118 forms a hydrogen-bonded junction in a helical unit that we term the central coupler, because it connects the catalytic centers to DNA and the sliding clamp. A suppressor mutation indicates that hydrogen bonding in the junction is important, and molecular dynamics simulations reveal that it maintains rigidity in the central coupler. The glutamine-mediated junction is preserved in diverse AAA+ ATPases, suggesting that a connected network of hydrogen bonds that links ATP molecules is an essential aspect of allosteric communication in these proteins.
Collapse
Affiliation(s)
- Subu Subramanian
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
| | - Kent Gorday
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Biophysics Graduate Group, University of California, BerkeleyBerkeleyUnited States
| | - Kendra Marcus
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
| | - Matthew R Orellana
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
| | - Peter Ren
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
| | - Xiao Ran Luo
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
| | - Michael E O'Donnell
- Howard Hughes Medical Institute, Rockefeller UniversityNew YorkUnited States
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative Biosciences (QB3), University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical Institute, University of California, BerkeleyBerkeleyUnited States
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
- Physical Biosciences Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| |
Collapse
|
20
|
Shaban K, Sauty SM, Yankulov K. Variation, Variegation and Heritable Gene Repression in S. cerevisiae. Front Genet 2021; 12:630506. [PMID: 33747046 PMCID: PMC7970126 DOI: 10.3389/fgene.2021.630506] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/08/2021] [Indexed: 11/13/2022] Open
Abstract
Phenotypic heterogeneity provides growth advantages for a population upon changes of the environment. In S. cerevisiae, such heterogeneity has been observed as "on/off" states in the expression of individual genes in individual cells. These variations can persist for a limited or extended number of mitotic divisions. Such traits are known to be mediated by heritable chromatin structures, by the mitotic transmission of transcription factors involved in gene regulatory circuits or by the cytoplasmic partition of prions or other unstructured proteins. The significance of such epigenetic diversity is obvious, however, we have limited insight into the mechanisms that generate it. In this review, we summarize the current knowledge of epigenetically maintained heterogeneity of gene expression and point out similarities and converging points between different mechanisms. We discuss how the sharing of limiting repression or activation factors can contribute to cell-to-cell variations in gene expression and to the coordination between short- and long- term epigenetic strategies. Finally, we discuss the implications of such variations and strategies in adaptation and aging.
Collapse
Affiliation(s)
- Kholoud Shaban
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Safia Mahabub Sauty
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Krassimir Yankulov
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| |
Collapse
|
21
|
Branigan TB, Kozono D, Schade AE, Deraska P, Rivas HG, Sambel L, Reavis HD, Shapiro GI, D'Andrea AD, DeCaprio JA. MMB-FOXM1-driven premature mitosis is required for CHK1 inhibitor sensitivity. Cell Rep 2021; 34:108808. [PMID: 33657372 PMCID: PMC7970065 DOI: 10.1016/j.celrep.2021.108808] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 12/24/2020] [Accepted: 02/09/2021] [Indexed: 12/25/2022] Open
Abstract
To identify genes whose loss confers resistance to CHK1 inhibitors, we perform genome-wide CRISPR-Cas9 screens in non-small-cell lung cancer (NSCLC) cell lines treated with the CHK1 inhibitor prexasertib (CHK1i). Five of the top six hits of the screens, MYBL2 (B-MYB), LIN54, FOXM1, cyclin A2 (CCNA2), and CDC25B, are cell-cycle-regulated genes that contribute to entry into mitosis. Knockout of MMB-FOXM1 complex components LIN54 and FOXM1 reduce CHK1i-induced DNA replication stress markers and premature mitosis during Late S phase. Activation of a feedback loop between the MMB-FOXM1 complex and CDK1 is required for CHK1i-induced premature mitosis in Late S phase and subsequent replication catastrophe, indicating that dysregulation of the S to M transition is necessary for CHK1 inhibitor sensitivity. These findings provide mechanistic insights into small molecule inhibitors currently studied in clinical trials and provide rationale for combination therapies. Branigan et al., by using genome-wide CRISPR screens, identify the MMB-FOXM1 complex as being required for CHK1 inhibitor (CHK1i) sensitivity. Their study shows that CHK1i-induced premature activation of the G2/M transcriptional program by this complex triggers a breakdown in the separation of DNA synthesis and mitosis, leading to replication catastrophe.
Collapse
Affiliation(s)
- Timothy B Branigan
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA, USA
| | - David Kozono
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Amy E Schade
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA, USA
| | - Peter Deraska
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Hembly G Rivas
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA, USA
| | - Larissa Sambel
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Hunter D Reavis
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Geoffrey I Shapiro
- Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Alan D D'Andrea
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Center for DNA Damage and Repair, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - James A DeCaprio
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, MA, USA; Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
22
|
Lee KY, Park SH. Eukaryotic clamp loaders and unloaders in the maintenance of genome stability. Exp Mol Med 2020; 52:1948-1958. [PMID: 33339954 PMCID: PMC8080817 DOI: 10.1038/s12276-020-00533-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 12/22/2022] Open
Abstract
Eukaryotic sliding clamp proliferating cell nuclear antigen (PCNA) plays a critical role as a processivity factor for DNA polymerases and as a binding and acting platform for many proteins. The ring-shaped PCNA homotrimer and the DNA damage checkpoint clamp 9-1-1 are loaded onto DNA by clamp loaders. PCNA can be loaded by the pentameric replication factor C (RFC) complex and the CTF18-RFC-like complex (RLC) in vitro. In cells, each complex loads PCNA for different purposes; RFC-loaded PCNA is essential for DNA replication, while CTF18-RLC-loaded PCNA participates in cohesion establishment and checkpoint activation. After completing its tasks, PCNA is unloaded by ATAD5 (Elg1 in yeast)-RLC. The 9-1-1 clamp is loaded at DNA damage sites by RAD17 (Rad24 in yeast)-RLC. All five RFC complex components, but none of the three large subunits of RLC, CTF18, ATAD5, or RAD17, are essential for cell survival; however, deficiency of the three RLC proteins leads to genomic instability. In this review, we describe recent findings that contribute to the understanding of the basic roles of the RFC complex and RLCs and how genomic instability due to deficiency of the three RLCs is linked to the molecular and cellular activity of RLC, particularly focusing on ATAD5 (Elg1). The attachment and removal of clamp proteins that encircle DNA as it is copied and assist its replication and maintenance is mediated by DNA clamp loader and unloader proteins; defects in loading and unloading can increase the rate of damaging mutations. Kyoo-young Lee and Su Hyung Park at the Institute for Basic Science in Ulsan, South Korea, review current understanding of the activity of clamp loading and unloading proteins. They examine research on the proteins in eukaryotic cells, those containing a cell nucleus, making their discussion relevant to understanding the stability of the human genome. They focus particular attention on a protein called ATAD5, which is involved in unloading the clamp proteins. Deficiencies in ATAD5 function have been implicated in genetic instability that might lead to several different types of cancer.
Collapse
Affiliation(s)
- Kyoo-Young Lee
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea.
| | - Su Hyung Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan, Korea
| |
Collapse
|
23
|
Francis NJ, Sihou D. Inheritance of Histone (H3/H4): A Binary Choice? Trends Biochem Sci 2020; 46:5-14. [PMID: 32917507 DOI: 10.1016/j.tibs.2020.08.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 08/09/2020] [Accepted: 08/14/2020] [Indexed: 02/07/2023]
Abstract
Histones carry information in the form of post-translational modifications (PTMs). For this information to be propagated through cell cycles, parental histones and their PTMs need to be maintained at the same genomic locations. Yet, during DNA replication, every nucleosome in the genome is disrupted to allow passage of the replisome. Recent data have identified histone chaperone activities that are intrinsic components of the replisome and implicate them in maintaining parental histones during DNA replication. We propose that structural and kinetic coordination between DNA replication and replisome-associated histone chaperone activities ensures positional inheritance of histones and their PTMs. When this coordination is perturbed, histones may instead be recycled to random genomic locations by alternative histone chaperones.
Collapse
Affiliation(s)
- Nicole J Francis
- Institut de Recherche Clinique de Montréal, 110 Avenue des Pins, Montréal, QC H2W 1R7, Canada; Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada; Division of Experimental Medicine, McGill University, 1001 Decarie Boulevard, Montreal, QC H4A 3J1, Canada.
| | - Djamouna Sihou
- Institut de Recherche Clinique de Montréal, 110 Avenue des Pins, Montréal, QC H2W 1R7, Canada; Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| |
Collapse
|
24
|
Thakar T, Leung W, Nicolae CM, Clements KE, Shen B, Bielinsky AK, Moldovan GL. Ubiquitinated-PCNA protects replication forks from DNA2-mediated degradation by regulating Okazaki fragment maturation and chromatin assembly. Nat Commun 2020; 11:2147. [PMID: 32358495 PMCID: PMC7195461 DOI: 10.1038/s41467-020-16096-w] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 04/14/2020] [Indexed: 12/11/2022] Open
Abstract
Upon genotoxic stress, PCNA ubiquitination allows for replication of damaged DNA by recruiting lesion-bypass DNA polymerases. However, PCNA is also ubiquitinated during normal S-phase progression. By employing 293T and RPE1 cells deficient in PCNA ubiquitination, generated through CRISPR/Cas9 gene editing, here, we show that this modification promotes cellular proliferation and suppression of genomic instability under normal growth conditions. Loss of PCNA-ubiquitination results in DNA2-dependent but MRE11-independent nucleolytic degradation of nascent DNA at stalled replication forks. This degradation is linked to defective gap-filling in the wake of the replication fork and incomplete Okazaki fragment maturation, which interferes with efficient PCNA unloading by ATAD5 and subsequent nucleosome deposition by CAF-1. Moreover, concomitant loss of PCNA-ubiquitination and the BRCA pathway results in increased nascent DNA degradation and PARP inhibitor sensitivity. In conclusion, we show that by ensuring efficient Okazaki fragment maturation, PCNA-ubiquitination protects fork integrity and promotes the resistance of BRCA-deficient cells to PARP-inhibitors.
Collapse
Affiliation(s)
- Tanay Thakar
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Wendy Leung
- Department of Biochemistry, Molecular Biology and Biophysics, College of Biological Sciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Claudia M Nicolae
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Kristen E Clements
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA
| | - Anja-Katrin Bielinsky
- Department of Biochemistry, Molecular Biology and Biophysics, College of Biological Sciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA.
| |
Collapse
|
25
|
Zhang W, Feng J, Li Q. The replisome guides nucleosome assembly during DNA replication. Cell Biosci 2020; 10:37. [PMID: 32190287 PMCID: PMC7066812 DOI: 10.1186/s13578-020-00398-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 02/29/2020] [Indexed: 12/18/2022] Open
Abstract
Nucleosome assembly during DNA replication is tightly coupled to ongoing DNA synthesis. This process, termed DNA replication-coupled (RC) nucleosome assembly, is essential for chromatin replication and has a great impact on both genome stability maintenance and epigenetic inheritance. This review discusses a set of recent findings regarding the role of replisome components contributing to RC nucleosome assembly. Starting with a brief introduction to the factors involved in nucleosome assembly and some aspects of the architecture of the eukaryotic replisome, we discuss studies from yeast to mammalian cells and the interactions of replisome components with histones and histone chaperones. We describe the proposed functions of replisome components during RC nucleosome assembly and discuss their impacts on histone segregation and implications for epigenetic inheritance.
Collapse
Affiliation(s)
- Wenshuo Zhang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871 China
| | - Jianxun Feng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871 China
| | - Qing Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871 China
| |
Collapse
|
26
|
Paul Solomon Devakumar LJ, Gaubitz C, Lundblad V, Kelch BA, Kubota T. Effective mismatch repair depends on timely control of PCNA retention on DNA by the Elg1 complex. Nucleic Acids Res 2020; 47:6826-6841. [PMID: 31114918 PMCID: PMC6648347 DOI: 10.1093/nar/gkz441] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/06/2019] [Accepted: 05/09/2019] [Indexed: 11/14/2022] Open
Abstract
Proliferating cell nuclear antigen (PCNA) is a sliding clamp that acts as a central co-ordinator for mismatch repair (MMR) as well as DNA replication. Loss of Elg1, the major subunit of the PCNA unloader complex, causes over-accumulation of PCNA on DNA and also increases mutation rate, but it has been unclear if the two effects are linked. Here we show that timely removal of PCNA from DNA by the Elg1 complex is important to prevent mutations. Although premature unloading of PCNA generally increases mutation rate, the mutator phenotype of elg1Δ is attenuated by PCNA mutants PCNA-R14E and PCNA-D150E that spontaneously fall off DNA. In contrast, the elg1Δ mutator phenotype is exacerbated by PCNA mutants that accumulate on DNA due to enhanced electrostatic PCNA–DNA interactions. Epistasis analysis suggests that PCNA over-accumulation on DNA interferes with both MMR and MMR-independent process(es). In elg1Δ, over-retained PCNA hyper-recruits the Msh2–Msh6 mismatch recognition complex through its PCNA-interacting peptide motif, causing accumulation of MMR intermediates. Our results suggest that PCNA retention controlled by the Elg1 complex is critical for efficient MMR: PCNA needs to be on DNA long enough to enable MMR, but if it is retained too long it interferes with downstream repair steps.
Collapse
Affiliation(s)
- Lovely Jael Paul Solomon Devakumar
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| | - Christl Gaubitz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | | | - Brian A Kelch
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Takashi Kubota
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, Scotland, UK
| |
Collapse
|
27
|
Brothers M, Rine J. Mutations in the PCNA DNA Polymerase Clamp of Saccharomyces cerevisiae Reveal Complexities of the Cell Cycle and Ploidy on Heterochromatin Assembly. Genetics 2019; 213:449-463. [PMID: 31451562 PMCID: PMC6781887 DOI: 10.1534/genetics.119.302452] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 08/23/2019] [Indexed: 01/19/2023] Open
Abstract
In Saccharomyces cerevisiae, transcriptional silencing at HML and HMR maintains mating-type identity. The repressive chromatin structure at these loci is replicated every cell cycle and must be re-established quickly to prevent transcription of the genes at these loci. Mutations in a component of the replisome, the proliferating cell nuclear antigen (PCNA), encoded by POL30, cause a loss of transcriptional silencing at HMR We used an assay that captures transient losses of silencing at HML and HMR to perform extended genetic analyses of the pol30-6, pol30-8, and pol30-79 alleles. All three alleles destabilized silencing only transiently and only in cycling cells. Whereas pol30-8 caused loss of silencing by disrupting the function of Chromatin Assembly Factor 1, pol30-6 and pol30-79 acted through a separate genetic pathway, but one still dependent on histone chaperones. Surprisingly, the silencing-loss phenotypes of pol30-6 and pol30-79 depended on ploidy, but not on POL30 dosage or mating-type identity. Separately from silencing loss, the pol30-6 and pol30-79 alleles also displayed high levels of mitotic recombination in diploids. These results established that histone trafficking involving PCNA at replication forks is crucial to the maintenance of chromatin state and genome stability during DNA replication. They also raised the possibility that increased ploidy may protect chromatin states when the replisome is perturbed.
Collapse
Affiliation(s)
- Molly Brothers
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
| | - Jasper Rine
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
| |
Collapse
|
28
|
Rowlands H, Shaban K, Cheng A, Foster B, Yankulov K. Dysfunctional CAF-I reveals its role in cell cycle progression and differential regulation of gene silencing. Cell Cycle 2019; 18:3223-3236. [PMID: 31564230 DOI: 10.1080/15384101.2019.1673100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Chromatin Assembly Factor I (CAF-I) plays a central role in the reassembly of H3/H4 histones during DNA replication. In S. cerevisiae CAF-I is not essential and its loss is associated with reduced gene silencing at telomeres and increased sensitivity to DNA damage. Two kinases, Cyclin Dependent Kinase (CDK) and Dbf4-Dependent Kinase (DDK), are known to phosphorylate the Cac1p subunit of CAF-I, but their role in the regulation of CAF-I activity is not well understood. In this study we systematically mutated the phosphorylation target sites of these kinases. We show that concomitant mutations of the CDK and DDK target sites of Cac1p lead to growth retardation and significant cell cycle defects, altered cell morphology and increased sensitivity to DNA damage. Surprisingly, some mutations also produced flocculation, a phenotype that is lost in most laboratory strains, and displayed elevated expression of FLO genes. None of these effects is observed upon the destruction of CAF-I. In contrast, the mutations that caused flocculation did not affect gene silencing at the mating type and subtelomeric loci. We conclude that dysfunctional CAF-I produces severe phenotypes, which reveal a possible role of CAF-I in the coordination of DNA replication, chromatin reassembly and cell cycle progression. Our study highlights the role of phosphorylation of Cac1p by CDK and a putative role for DDK in the transmission and re-assembly of chromatin during DNA replication.
Collapse
Affiliation(s)
- Hollie Rowlands
- Department of Molecular and Cellular Biology, University of Guelph , Guelph , Canada
| | - Kholoud Shaban
- Department of Molecular and Cellular Biology, University of Guelph , Guelph , Canada
| | - Ashley Cheng
- Department of Molecular and Cellular Biology, University of Guelph , Guelph , Canada
| | - Barret Foster
- Department of Molecular and Cellular Biology, University of Guelph , Guelph , Canada
| | - Krassimir Yankulov
- Department of Molecular and Cellular Biology, University of Guelph , Guelph , Canada
| |
Collapse
|
29
|
Rowlands H, Shaban K, Foster B, Proteau Y, Yankulov K. Histone chaperones and the Rrm3p helicase regulate flocculation in S. cerevisiae. Epigenetics Chromatin 2019; 12:56. [PMID: 31547833 PMCID: PMC6757361 DOI: 10.1186/s13072-019-0303-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 09/03/2019] [Indexed: 12/16/2022] Open
Abstract
Background Biofilm formation or flocculation is a major phenotype in wild type budding yeasts but rarely seen in laboratory yeast strains. Here, we analysed flocculation phenotypes and the expression of FLO genes in laboratory strains with various genetic backgrounds. Results We show that mutations in histone chaperones, the helicase RRM3 and the Histone Deacetylase HDA1 de-repress the FLO genes and partially reconstitute flocculation. We demonstrate that the loss of repression correlates to elevated expression of several FLO genes, to increased acetylation of histones at the promoter of FLO1 and to variegated expression of FLO11. We show that these effects are related to the activity of CAF-1 at the replication forks. We also demonstrate that nitrogen starvation or inhibition of histone deacetylases do not produce flocculation in W303 and BY4742 strains but do so in strains compromised for chromatin maintenance. Finally, we correlate the de-repression of FLO genes to the loss of silencing at the subtelomeric and mating type gene loci. Conclusions We conclude that the deregulation of chromatin maintenance and transmission is sufficient to reconstitute flocculation in laboratory yeast strains. Consequently, we propose that a gain in epigenetic silencing is a major contributing factor for the loss of flocculation phenotypes in these strains. We suggest that flocculation in yeasts provides an excellent model for addressing the challenging issue of how epigenetic mechanisms contribute to evolution.
Collapse
Affiliation(s)
- Hollie Rowlands
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Kholoud Shaban
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Barret Foster
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Yannic Proteau
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Krassimir Yankulov
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada.
| |
Collapse
|
30
|
Abo-Elfadl MT, Gamal-Eldeen AM, Ismail MF, Shahin NN. Silencing of the cytokine receptor TNFRSF13B: A new therapeutic target for triple-negative breast cancer. Cytokine 2019; 125:154790. [PMID: 31400636 DOI: 10.1016/j.cyto.2019.154790] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 07/20/2019] [Accepted: 07/23/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND TNFRSF13B, TACI, is a member of the TNF receptor superfamily; it plays a key role in cancer cell proliferation and progression. METHOD Influence of silencing of human cytokine receptors on cell viability was screened by Luminescent Cell Viability Assay, after transfection of the siRNA library to find the maximum cell death superhits in both triple-negative MDA-MB-231 and double-positive MCF7 breast cells. The mode of cell death was investigated by dual DNA fluorescence staining. The expression of mRNAs of TACI, BAFF, BAFF-R, and APRIL was explored by qPCR. Immunocytofluorescence analysis was used to evaluate changes in TACI, Bcl-2, TNFR2, cyclin-D2, and PCNA. NF-kB p65, cell cycle, and necrosis/apoptosis (late and early) were analyzed by flow cytometry. RESULTS TACI is the most potent cytotoxic superhit resulted from high-throughput screening of the siRNA library, in both types of cells. Our findings indicated that silencing receptor TACI in both types of breast cancer cells led to significant cell death, after different intervals from siRNA transfection. Cell death mediators (TNFR2, Bcl-2, and NF-κB) were significantly decreased after TACI silencing. The key factors for cell division (Cyclin-D2 and PCNA) were significantly increased in silenced cells of both types but the cell cycle was arrested before the completion of mitosis. Expression of BAFF, BAFF-R and APRIL mRNA in TACI-silenced cells showed significant upregulation in MDA-MB-231 cells, while only BAFF-R and APRIL showed significant downregulation in MCF7 cells. CONCLUSION TACI silencing can be a new and promising therapeutic target for mesenchymal-stem like triple-negative breast cancer subtype.
Collapse
Affiliation(s)
- Mahmoud T Abo-Elfadl
- Cancer Biology and Genetics Laboratory, Centre of Excellence for Advanced Sciences, National Research Centre, Dokki, 12622 Cairo, Egypt; Biochemistry Department, National Research Centre, Dokki, Cairo, Egypt
| | - Amira M Gamal-Eldeen
- Cancer Biology and Genetics Laboratory, Centre of Excellence for Advanced Sciences, National Research Centre, Dokki, 12622 Cairo, Egypt; Biochemistry Department, National Research Centre, Dokki, Cairo, Egypt; Clinical Laboratory Department, College of Applied Medical Sciences, Taif University, Al Mutamarat Rd, Al Mathnah, At Taif 26521, Saudi Arabia.
| | - Manal F Ismail
- Biochemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Nancy N Shahin
- Biochemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| |
Collapse
|
31
|
Gali VK, Dickerson D, Katou Y, Fujiki K, Shirahige K, Owen-Hughes T, Kubota T, Donaldson AD. Identification of Elg1 interaction partners and effects on post-replication chromatin re-formation. PLoS Genet 2018; 14:e1007783. [PMID: 30418970 PMCID: PMC6258251 DOI: 10.1371/journal.pgen.1007783] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 11/26/2018] [Accepted: 10/23/2018] [Indexed: 12/04/2022] Open
Abstract
Elg1, the major subunit of a Replication Factor C-like complex, is critical to ensure genomic stability during DNA replication, and is implicated in controlling chromatin structure. We investigated the consequences of Elg1 loss for the dynamics of chromatin re-formation following DNA replication. Measurement of Okazaki fragment length and the micrococcal nuclease sensitivity of newly replicated DNA revealed a defect in nucleosome organization in the absence of Elg1. Using a proteomic approach to identify Elg1 binding partners, we discovered that Elg1 interacts with Rtt106, a histone chaperone implicated in replication-coupled nucleosome assembly that also regulates transcription. A central role for Elg1 is the unloading of PCNA from chromatin following DNA replication, so we examined the relative importance of Rtt106 and PCNA unloading for chromatin reassembly following DNA replication. We find that the major cause of the chromatin organization defects of an ELG1 mutant is PCNA retention on DNA following replication, with Rtt106-Elg1 interaction potentially playing a contributory role.
Collapse
Affiliation(s)
- Vamsi K. Gali
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, Scotland, United Kingdom
| | - David Dickerson
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, Scotland, United Kingdom
| | - Yuki Katou
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan
| | - Katsunori Fujiki
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan
| | - Katsuhiko Shirahige
- Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan
| | - Tom Owen-Hughes
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, Scotland, United Kingdom
| | - Takashi Kubota
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, Scotland, United Kingdom
| | - Anne D. Donaldson
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, Scotland, United Kingdom
| |
Collapse
|
32
|
Zhao WP, Wang HW, Liu J, Tan PP, Lin L, Zhou BH. JNK/STAT signalling pathway is involved in fluoride-induced follicular developmental dysplasia in female mice. CHEMOSPHERE 2018; 209:88-95. [PMID: 29913403 DOI: 10.1016/j.chemosphere.2018.06.086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 06/10/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
Excessive fluoride (F) intake decreases the development of potential oocytes by inducing oxidative stress and apoptosis in female mice in our previous study. This study aims to investigate the underlying mechanisms of F-induced follicular developmental dysplasia. Pathomorphological changes in the ovary tissues were observed under light and transmission electron microscopes. DNA damage and proliferation in granulosa cells were analysed by TUNEL staining and BrdU measurement. The protein expression of cell proliferation related regulatory factors including JNK, STAT3, STAT5, CDK2, CDK4, PCNA and Ki67 in the ovary tissues was measured by immunohistochemistry and Western blot analyses. Results indicated that the structure of granulosa cells in the ovary was seriously damaged by excessive F, evident by the swollen endoplasmic reticulum, mitochondria with vacuoles and nucleus shrinkage. F treatment also considerably enhanced the apoptosis and inhibited the proliferation of granulosa cells. The number of granulosa cells around the oocyte decreased after F treatment. The expression levels of STAT3, CDK2, CDK4 and Ki67 in the ovary tissues were up-regulated, and STAT5 and PCNA did not change significantly after F treatment, whereas JNK expression was down-regulated with increasing F dose. In summary, changes in the expression levels of JNK, STAT3, STAT5, CDK2, CDK4, PCNA and Ki67 in the JNK/STAT signalling pathway are involved in F-induced follicular dysplasia in the ovary.
Collapse
Affiliation(s)
- Wen-Peng Zhao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan 471000, PR China
| | - Hong-Wei Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan 471000, PR China.
| | - Jing Liu
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan 471000, PR China
| | - Pan-Pan Tan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan 471000, PR China
| | - Lin Lin
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan 471000, PR China
| | - Bian-Hua Zhou
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan 471000, PR China.
| |
Collapse
|
33
|
Yu C, Gan H, Serra-Cardona A, Zhang L, Gan S, Sharma S, Johansson E, Chabes A, Xu RM, Zhang Z. A mechanism for preventing asymmetric histone segregation onto replicating DNA strands. Science 2018; 361:1386-1389. [PMID: 30115745 PMCID: PMC6597248 DOI: 10.1126/science.aat8849] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/30/2018] [Indexed: 12/11/2022]
Abstract
How parental histone (H3-H4)2 tetramers, the primary carriers of epigenetic modifications, are transferred onto leading and lagging strands of DNA replication forks for epigenetic inheritance remains elusive. Here we show that parental (H3-H4)2 tetramers are assembled into nucleosomes onto both leading and lagging strands, with a slight preference for lagging strands. The lagging-strand preference increases markedly in budding yeast cells lacking Dpb3 and Dpb4, two subunits of the leading strand DNA polymerase, Pol ε, owing to the impairment of parental (H3-H4)2 transfer to leading strands. Dpb3-Dpb4 binds H3-H4 in vitro and participates in the inheritance of heterochromatin. These results indicate that different proteins facilitate the transfer of parental (H3-H4)2 onto leading versus lagging strands and that Dbp3-Dpb4 plays an important role in this poorly understood process.
Collapse
Affiliation(s)
- Chuanhe Yu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Haiyun Gan
- Institute for Cancer Genetics, Department of Pediatrics and Genetics and Development, Columbia University, New York, NY 10032, USA
| | - Albert Serra-Cardona
- Institute for Cancer Genetics, Department of Pediatrics and Genetics and Development, Columbia University, New York, NY 10032, USA
| | - Lin Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Songlin Gan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, SE 90187 Umeå, Sweden
| | - Erik Johansson
- Department of Medical Biochemistry and Biophysics, Umeå University, SE 90187 Umeå, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, SE 90187 Umeå, Sweden
| | - Rui-Ming Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiguo Zhang
- Institute for Cancer Genetics, Department of Pediatrics and Genetics and Development, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
34
|
Gan H, Serra-Cardona A, Hua X, Zhou H, Labib K, Yu C, Zhang Z. The Mcm2-Ctf4-Polα Axis Facilitates Parental Histone H3-H4 Transfer to Lagging Strands. Mol Cell 2018; 72:140-151.e3. [PMID: 30244834 DOI: 10.1016/j.molcel.2018.09.001] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 08/27/2018] [Accepted: 08/30/2018] [Indexed: 12/20/2022]
Abstract
Although essential for epigenetic inheritance, the transfer of parental histone (H3-H4)2 tetramers that contain epigenetic modifications to replicating DNA strands is poorly understood. Here, we show that the Mcm2-Ctf4-Polα axis facilitates the transfer of parental (H3-H4)2 tetramers to lagging-strand DNA at replication forks. Mutating the conserved histone-binding domain of the Mcm2 subunit of the CMG (Cdc45-MCM-GINS) DNA helicase, which translocates along the leading-strand template, results in a marked enrichment of parental (H3-H4)2 on leading strand, due to the impairment of the transfer of parental (H3-H4)2 to lagging strands. Similar effects are observed in Ctf4 and Polα primase mutants that disrupt the connection of the CMG helicase to Polα that resides on lagging-strand template. Our results support a model whereby parental (H3-H4)2 complexes displaced from nucleosomes by DNA unwinding at replication forks are transferred by the CMG-Ctf4-Polα complex to lagging-strand DNA for nucleosome assembly at the original location.
Collapse
Affiliation(s)
- Haiyun Gan
- Institute for Cancer Genetics, Department of Pediatrics and Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Albert Serra-Cardona
- Institute for Cancer Genetics, Department of Pediatrics and Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Xu Hua
- Institute for Cancer Genetics, Department of Pediatrics and Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Hui Zhou
- Institute for Cancer Genetics, Department of Pediatrics and Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Karim Labib
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Chuanhe Yu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA.
| | - Zhiguo Zhang
- Institute for Cancer Genetics, Department of Pediatrics and Genetics and Development, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
| |
Collapse
|