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Arroyo M, Casas-Delucchi CS, Pabba MK, Prorok P, Pradhan SK, Rausch C, Lehmkuhl A, Maiser A, Buschbeck M, Pasque V, Bernstein E, Luck K, Cardoso MC. Histone variant macroH2A1 regulates synchronous firing of replication origins in the inactive X chromosome. Nucleic Acids Res 2024:gkae734. [PMID: 39189450 DOI: 10.1093/nar/gkae734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 08/07/2024] [Accepted: 08/14/2024] [Indexed: 08/28/2024] Open
Abstract
MacroH2A has been linked to transcriptional silencing, cell identity, and is a hallmark of the inactive X chromosome (Xi). However, it remains unclear whether macroH2A plays a role in DNA replication. Using knockdown/knockout cells for each macroH2A isoform, we show that macroH2A-containing nucleosomes slow down replication progression rate in the Xi reflecting the higher nucleosome stability. Moreover, macroH2A1, but not macroH2A2, regulates the number of nano replication foci in the Xi, and macroH2A1 downregulation increases DNA loop sizes corresponding to replicons. This relates to macroH2A1 regulating replicative helicase loading during G1 by interacting with it. We mapped this interaction to a phenylalanine in macroH2A1 that is not conserved in macroH2A2 and the C-terminus of Mcm3 helicase subunit. We propose that macroH2A1 enhances the licensing of pre-replication complexes via DNA helicase interaction and loading onto the Xi.
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Affiliation(s)
- Maria Arroyo
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Corella S Casas-Delucchi
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Maruthi K Pabba
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Paulina Prorok
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Sunil K Pradhan
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Cathia Rausch
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Anne Lehmkuhl
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
| | - Andreas Maiser
- Faculty of Biology and Center for Molecular Biosystems (BioSysM), Human Biology and BioImaging, LMU Munich, Munich 81377, Germany
| | - Marcus Buschbeck
- Program of Myeloid Neoplasms, Program of Applied Epigenetics, Josep Carreras Leukaemia Research Institute (IJC), Germans Trias i Pujol Research Institute (IGTP), Campus Can Ruti, Camí de les Escoles, 08916 Badalona, Barcelona, Spain
| | - Vincent Pasque
- Department of Development and Regeneration, Leuven Stem Cell Institute, Leuven Institute for Single-Cell Omics (LISCO), KU Leuven-University of Leuven, 3000 Leuven, Belgium
| | - Emily Bernstein
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, Tisch Cancer Institute, NY, NY 10029, USA
| | - Katja Luck
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - M Cristina Cardoso
- Cell Biology and Epigenetics, Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany
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2
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Xie Z, Lu H, Zheng J, Song J, Sun K. Origin recognition complex subunit 6 (ORC6) is a key mediator of LPS-induced NFκB activation and the pro-inflammatory response. Cell Commun Signal 2024; 22:399. [PMID: 39143485 PMCID: PMC11323635 DOI: 10.1186/s12964-024-01768-7] [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: 06/06/2024] [Accepted: 07/27/2024] [Indexed: 08/16/2024] Open
Abstract
Lipopolysaccharide (LPS)-activated pro-inflammatory responses play a critical role in sepsis, a life-threatening condition. This study investigates the role of origin recognition complex subunit 6 (ORC6) in LPS responses in macrophages and monocytes. Silencing ORC6 using targeted shRNA significantly reduced LPS-induced expression and production of IL-1β (interleukin-1 beta), TNF-α (tumor necrosis factor alpha), and IL-6 (interleukin-6) in THP-1 human macrophages, peripheral blood mononuclear cells (PBMCs), and bone marrow-derived macrophages (BMDMs). Additionally, ORC6 knockout (KO) via the CRISPR/Cas9 method in THP-1 macrophages inhibited LPS-induced pro-inflammatory responses, while ectopic overexpression of ORC6 enhanced LPS-induced expression and production of pro-inflammatory cytokines. ORC6 is crucial for the activation of the nuclear factor kappa B (NFκB) signaling cascade in macrophages and monocytes. LPS-induced NFκB activation was largely inhibited by ORC6 silencing or KO, but potentiated following ORC6 overexpression. Mechanistically, ORC6 associated with nuclear p65 after LPS stimulation, an interaction necessary for NFκB activation. Overexpression of ORC6 did not recover the reduced pro-inflammatory response to LPS in THP-1 macrophages with silenced p65. Furthermore, the NFκB inhibitor BMS-345,541 nearly eliminated the pro-inflammatory response enhanced by ORC6 overexpression in response to LPS. Further studies revealed that ORC6 depletion inhibited NFκB activation induced by double-stranded RNA (dsRNA) and high mobility group box 1 (HMGB1) in THP-1 macrophages. In vivo experiments demonstrated that macrophage-specific knockdown of ORC6 protected mice from LPS-induced septic shock and inhibited LPS-stimulated production of IL-1β, TNF-α, and IL-6 in mouse serum. ORC6 silencing also inhibited LPS-induced NFκB activation in ex vivo cultured PBMCs following macrophage-specific knockdown of ORC6. These findings highlight ORC6 as a pivotal mediator in LPS-induced NFκB activation and the pro-inflammatory response in sepsis, suggesting that targeting ORC6 could be a novel therapeutic strategy for managing sepsis and related inflammatory conditions.
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Affiliation(s)
- Zichen Xie
- Emergency Department, Minhang Hospital, Fudan University, Shanghai, China
| | - Haisu Lu
- Emergency Department, Minhang Hospital, Fudan University, Shanghai, China
| | - Jiayi Zheng
- Emergency Department, Minhang Hospital, Fudan University, Shanghai, China
| | - Jianfeng Song
- Emergency Department, Minhang Hospital, Fudan University, Shanghai, China.
| | - Keyu Sun
- Emergency Department, Minhang Hospital, Fudan University, Shanghai, China.
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Yang WL, Zhang WF, Wang Y, Lou Y, Cai Y, Zhu J. Origin recognition complex 6 overexpression promotes growth of glioma cells. Cell Death Dis 2024; 15:485. [PMID: 38971772 PMCID: PMC11227543 DOI: 10.1038/s41419-024-06764-w] [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: 01/05/2024] [Revised: 05/19/2024] [Accepted: 05/21/2024] [Indexed: 07/08/2024]
Abstract
The discovery of novel oncotargets for glioma is of immense significance. We here explored the expression patterns, biological functions, and underlying mechanisms associated with ORC6 (origin recognition complex 6) in glioma. Through the bioinformatics analyses, we found a significant increase in ORC6 expression within human glioma tissues, correlating with poorer overall survival, higher tumor grade, and wild-type isocitrate dehydrogenase status. Additionally, ORC6 overexpression is detected in glioma tissues obtained from locally-treated patients and across various primary/established glioma cells. Further bioinformatics scrutiny revealed that genes co-expressed with ORC6 are enriched in multiple signaling cascades linked to cancer. In primary and immortalized (A172) glioma cells, depleting ORC6 using specific shRNA or Cas9-sgRNA knockout (KO) significantly decreased cell viability and proliferation, disrupted cell cycle progression and mobility, and triggered apoptosis. Conversely, enhancing ORC6 expression via a lentiviral construct augmented malignant behaviors in human glioma cells. ORC6 emerged as a crucial regulator for the expression of key oncogenic genes, including Cyclin A2, Cyclin B2, and DNA topoisomerase II (TOP2A), within glioma cells. Silencing or KO of ORC6 reduced the mRNA and protein levels of these genes, while overexpression of ORC6 increased their expression in primary glioma cells. Bioinformatics analyses further identified RBPJ as a potential transcription factor of ORC6. RBPJ shRNA decreased ORC6 expression in primary glioma cells, while its overexpression increased it. Additionally, significantly enhanced binding between the RBPJ protein and the proposed ORC6 promoter region was detected in glioma tissues and cells. In vivo experiments demonstrated a significant reduction in the growth of patient-derived glioma xenografts in the mouse brain subsequent to ORC6 KO. ORC6 depletion, inhibited proliferation, decreased expression of Cyclin A2/B2/TOP2A, and increased apoptosis were detected within these ORC6 KO intracranial glioma xenografts. Altogether, RBPJ-driven ORC6 overexpression promotes glioma cell growth, underscoring its significance as a promising therapeutic target.
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Affiliation(s)
- Wen-Lei Yang
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wei-Feng Zhang
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yin Wang
- Department of Radiotherapy and Oncology, Affiliated Kunshan Hospital of Jiangsu University, Kunshan, China
| | - Yue Lou
- School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong University, Shanghai, China
| | - Yu Cai
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Jun Zhu
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Ahmad H, Chetlangia N, Prasanth SG. Chromatin's Influence on Pre-Replication Complex Assembly and Function. BIOLOGY 2024; 13:152. [PMID: 38534422 DOI: 10.3390/biology13030152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 02/19/2024] [Accepted: 02/19/2024] [Indexed: 03/28/2024]
Abstract
In all eukaryotes, the initiation of DNA replication requires a stepwise assembly of factors onto the origins of DNA replication. This is pioneered by the Origin Recognition Complex, which recruits Cdc6. Together, they bring Cdt1, which shepherds MCM2-7 to form the OCCM complex. Sequentially, a second Cdt1-bound hexamer of MCM2-7 is recruited by ORC-Cdc6 to form an MCM double hexamer, which forms a part of the pre-RC. Although the mechanism of ORC binding to DNA varies across eukaryotes, how ORC is recruited to replication origins in human cells remains an area of intense investigation. This review discusses how the chromatin environment influences pre-RC assembly, function, and, eventually, origin activity.
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Affiliation(s)
- Hina Ahmad
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801, USA
| | - Neha Chetlangia
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801, USA
| | - Supriya G Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801, USA
- Cancer Center at Illinois, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
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5
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Dementieva NV, Dysin AP, Shcherbakov YS, Nikitkina EV, Musidray AA, Petrova AV, Mitrofanova OV, Plemyashov KV, Azovtseva AI, Griffin DK, Romanov MN. Risk of Sperm Disorders and Impaired Fertility in Frozen-Thawed Bull Semen: A Genome-Wide Association Study. Animals (Basel) 2024; 14:251. [PMID: 38254422 PMCID: PMC10812825 DOI: 10.3390/ani14020251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 01/08/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Cryopreservation is a widely used method of semen conservation in animal breeding programs. This process, however, can have a detrimental effect on sperm quality, especially in terms of its morphology. The resultant sperm disorders raise the risk of reduced sperm fertilizing ability, which poses a serious threat to the long-term efficacy of livestock reproduction and breeding. Understanding the genetic factors underlying these effects is critical for maintaining sperm quality during cryopreservation, and for animal fertility in general. In this regard, we performed a genome-wide association study to identify genomic regions associated with various cryopreservation sperm abnormalities in Holstein cattle, using single nucleotide polymorphism (SNP) markers via a high-density genotyping assay. Our analysis revealed a significant association of specific SNPs and candidate genes with absence of acrosomes, damaged cell necks and tails, as well as wrinkled acrosomes and decreased motility of cryopreserved sperm. As a result, we identified candidate genes such as POU6F2, LPCAT4, DPYD, SLC39A12 and CACNB2, as well as microRNAs (bta-mir-137 and bta-mir-2420) that may play a critical role in sperm morphology and disorders. These findings provide crucial information on the molecular mechanisms underlying acrosome integrity, motility, head abnormalities and damaged cell necks and tails of sperm after cryopreservation. Further studies with larger sample sizes, genome-wide coverage and functional validation are needed to explore causal variants in more detail, thereby elucidating the mechanisms mediating these effects. Overall, our results contribute to the understanding of genetic architecture in cryopreserved semen quality and disorders in bulls, laying the foundation for improved animal reproduction and breeding.
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Affiliation(s)
- Natalia V. Dementieva
- Russian Research Institute of Farm Animal Genetics and Breeding—Branch of the L. K. Ernst Federal Research Centre for Animal Husbandry, Pushkin, 196601 St. Petersburg, Russia; (A.P.D.); (Y.S.S.); (E.V.N.); (A.A.M.); (A.V.P.); (O.V.M.); (A.I.A.)
| | - Artem P. Dysin
- Russian Research Institute of Farm Animal Genetics and Breeding—Branch of the L. K. Ernst Federal Research Centre for Animal Husbandry, Pushkin, 196601 St. Petersburg, Russia; (A.P.D.); (Y.S.S.); (E.V.N.); (A.A.M.); (A.V.P.); (O.V.M.); (A.I.A.)
| | - Yuri S. Shcherbakov
- Russian Research Institute of Farm Animal Genetics and Breeding—Branch of the L. K. Ernst Federal Research Centre for Animal Husbandry, Pushkin, 196601 St. Petersburg, Russia; (A.P.D.); (Y.S.S.); (E.V.N.); (A.A.M.); (A.V.P.); (O.V.M.); (A.I.A.)
| | - Elena V. Nikitkina
- Russian Research Institute of Farm Animal Genetics and Breeding—Branch of the L. K. Ernst Federal Research Centre for Animal Husbandry, Pushkin, 196601 St. Petersburg, Russia; (A.P.D.); (Y.S.S.); (E.V.N.); (A.A.M.); (A.V.P.); (O.V.M.); (A.I.A.)
| | - Artem A. Musidray
- Russian Research Institute of Farm Animal Genetics and Breeding—Branch of the L. K. Ernst Federal Research Centre for Animal Husbandry, Pushkin, 196601 St. Petersburg, Russia; (A.P.D.); (Y.S.S.); (E.V.N.); (A.A.M.); (A.V.P.); (O.V.M.); (A.I.A.)
| | - Anna V. Petrova
- Russian Research Institute of Farm Animal Genetics and Breeding—Branch of the L. K. Ernst Federal Research Centre for Animal Husbandry, Pushkin, 196601 St. Petersburg, Russia; (A.P.D.); (Y.S.S.); (E.V.N.); (A.A.M.); (A.V.P.); (O.V.M.); (A.I.A.)
| | - Olga V. Mitrofanova
- Russian Research Institute of Farm Animal Genetics and Breeding—Branch of the L. K. Ernst Federal Research Centre for Animal Husbandry, Pushkin, 196601 St. Petersburg, Russia; (A.P.D.); (Y.S.S.); (E.V.N.); (A.A.M.); (A.V.P.); (O.V.M.); (A.I.A.)
| | - Kirill V. Plemyashov
- Federal State Budgetary Educational Institution of Higher Education “St. Petersburg State University of Veterinary Medicine”, 196084 St. Petersburg, Russia;
| | - Anastasiia I. Azovtseva
- Russian Research Institute of Farm Animal Genetics and Breeding—Branch of the L. K. Ernst Federal Research Centre for Animal Husbandry, Pushkin, 196601 St. Petersburg, Russia; (A.P.D.); (Y.S.S.); (E.V.N.); (A.A.M.); (A.V.P.); (O.V.M.); (A.I.A.)
| | | | - Michael N. Romanov
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK;
- L. K. Ernst Federal Research Centre for Animal Husbandry, Dubrovitsy, 142132 Podolsk, Moscow Oblast, Russia
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6
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Liu SW, Luo JQ, Zhao LY, Ou NJ, Chao-Yang, Zhang YX, Bai HW, Sun HF, Zhang JX, Yao CC, Li P, Tian RH, Li Z, Zhu ZJ. scRNA-seq reveals that origin recognition complex subunit 6 regulates mouse spermatogonial cell proliferation and apoptosis via activation of Wnt/β-catenin signaling. Asian J Androl 2024; 26:46-56. [PMID: 37788012 PMCID: PMC10846824 DOI: 10.4103/aja202330] [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: 02/01/2023] [Accepted: 06/26/2023] [Indexed: 10/04/2023] Open
Abstract
The regulation of spermatogonial proliferation and apoptosis is of great significance for maintaining spermatogenesis. The single-cell RNA sequencing (scRNA-seq) analysis of the testis was performed to identify genes upregulated in spermatogonia. Using scRNA-seq analysis, we identified the spermatogonia upregulated gene origin recognition complex subunit 6 ( Orc6 ), which is involved in DNA replication and cell cycle regulation; its protein expression in the human and mouse testis was detected by western blot and immunofluorescence. To explore the potential function of Orc6 in spermatogonia, the C18-4 cell line was transfected with control or Orc6 siRNA. Subsequently, 5-ethynyl-2-deoxyuridine (EdU) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays, flow cytometry, and western blot were used to evaluate its effects on proliferation and apoptosis. It was revealed that ORC6 could promote proliferation and inhibit apoptosis of C18-4 cells. Bulk RNA sequencing and bioinformatics analysis indicated that Orc6 was involved in the activation of wingless/integrated (Wnt)/β-catenin signaling. Western blot revealed that the expression of β-catenin protein and its phosphorylation (Ser675) were significantly decreased when silencing the expression of ORC6. Our findings indicated that Orc6 was upregulated in spermatogonia, whereby it regulated proliferation and apoptosis by activating Wnt/β-catenin signaling.
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Affiliation(s)
- Shi-Wei Liu
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Jia-Qiang Luo
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Liang-Yu Zhao
- Department of Urology, Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai 519000, China
| | - Ning-Jing Ou
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Chao-Yang
- Department of Urology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Yu-Xiang Zhang
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Hao-Wei Bai
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Hong-Fang Sun
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Jian-Xiong Zhang
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Chen-Cheng Yao
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Peng Li
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Ru-Hui Tian
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Zheng Li
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
| | - Zi-Jue Zhu
- Department of Andrology, Center for Men’s Health, Urologic Medical Center, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Shanghai Key Lab of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
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7
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Mas AM, Goñi E, Ruiz de Los Mozos I, Arcas A, Statello L, González J, Blázquez L, Lee WTC, Gupta D, Sejas Á, Hoshina S, Armaos A, Tartaglia GG, Waga S, Ule J, Rothenberg E, Gómez M, Huarte M. ORC1 binds to cis-transcribed RNAs for efficient activation of replication origins. Nat Commun 2023; 14:4447. [PMID: 37488096 PMCID: PMC10366126 DOI: 10.1038/s41467-023-40105-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/11/2023] [Indexed: 07/26/2023] Open
Abstract
Cells must coordinate the activation of thousands of replication origins dispersed throughout their genome. Active transcription is known to favor the formation of mammalian origins, although the role that RNA plays in this process remains unclear. We show that the ORC1 subunit of the human Origin Recognition Complex interacts with RNAs transcribed from genes with origins in their transcription start sites (TSSs), displaying a positive correlation between RNA binding and origin activity. RNA depletion, or the use of ORC1 RNA-binding mutant, result in inefficient activation of proximal origins, linked to impaired ORC1 chromatin release. ORC1 RNA binding activity resides in its intrinsically disordered region, involved in intra- and inter-molecular interactions, regulation by phosphorylation, and phase-separation. We show that RNA binding favors ORC1 chromatin release, by regulating its phosphorylation and subsequent degradation. Our results unveil a non-coding function of RNA as a dynamic component of the chromatin, orchestrating the activation of replication origins.
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Affiliation(s)
- Aina Maria Mas
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Enrique Goñi
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Igor Ruiz de Los Mozos
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Aida Arcas
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Luisa Statello
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Jovanna González
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Lorea Blázquez
- RNA Networks Lab, The Francis Crick Institute, NW11BF, London, UK
- Neurosciences Area, Biodonostia Health Research Institute, 20014, San Sebastian, Spain
- Ikerbasque, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Wei Ting Chelsea Lee
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, NY, 10016, USA
| | - Dipika Gupta
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, NY, 10016, USA
| | - Álvaro Sejas
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain
| | - Shoko Hoshina
- Department of Chemical and Biological Sciences, Japan Women's University, Tokyo, 112-8681, Japan
| | - Alexandros Armaos
- Center for Human Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Gian Gaetano Tartaglia
- Center for Human Technologies, Istituto Italiano di Tecnologia, Genova, Italy
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Department of Biology 'Charles Darwin', Sapienza University of Rome, Rome, Italy
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Shou Waga
- Department of Chemical and Biological Sciences, Japan Women's University, Tokyo, 112-8681, Japan
| | - Jernej Ule
- RNA Networks Lab, The Francis Crick Institute, NW11BF, London, UK
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, Perlmutter Cancer Center, New York University School of Medicine, New York, NY, 10016, USA
| | - María Gómez
- Centro de Biología Molecular Severo Ochoa (CBMSO), Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid (CSIC/UAM), Nicolás Cabrera 1, 28049, Madrid, Spain
| | - Maite Huarte
- Center for Applied Medical Research, University of Navarra, Pio XII 55 Ave, 31008, Pamplona, Spain.
- Institute of Health Research of Navarra (IdiSNA), Cancer Center Clínica Universidad de Navarra (CCUN), Pamplona, Spain.
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8
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Halgasova N, Javorova R, Bocanova L, Krajcikova D, Bauer JA, Bukovska G. Characterization of a newly discovered putative DNA replication initiator from Paenibacillus polymyxa phage phiBP. Microbiol Res 2023; 274:127437. [PMID: 37327604 DOI: 10.1016/j.micres.2023.127437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/08/2023] [Accepted: 06/10/2023] [Indexed: 06/18/2023]
Abstract
The bacteriophage phiBP contains a newly discovered putative replisome organizer, a helicase loader, and a beta clamp, which together may serve to replicate its DNA. Bioinformatics analysis of the phiBP replisome organizer sequence showed that it belongs to a recently identified family of putative initiator proteins. We prepared and isolated a wild type-like recombinant protein, gpRO-HC, and a mutant protein gpRO-HCK8A, containing a lysine to alanine substitution at position 8. gpRO-HC had low ATPase activity regardless of the presence of DNA, while the ATPase activity of the mutant was significantly higher. gpRO-HC bound to both single- and double-stranded DNA substrates. Different methods showed that gpRO-HC forms higher oligomers containing about 12 subunits. This work provides the first information about another group of phage initiator proteins, which trigger DNA replication in phages infecting low GC Gram-positive bacteria.
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Affiliation(s)
- Nora Halgasova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Rachel Javorova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Lucia Bocanova
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Daniela Krajcikova
- Department of Microbial Genetics, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Jacob A Bauer
- Department of Biochemistry and Protein Structure, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
| | - Gabriela Bukovska
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava, Slovakia.
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9
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Liu D, Sonalkar J, Prasanth SG. ORChestra coordinates the replication and repair music. Bioessays 2023; 45:e2200229. [PMID: 36811379 PMCID: PMC10023367 DOI: 10.1002/bies.202200229] [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: 11/29/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/24/2023]
Abstract
Error-free genome duplication and accurate cell division are critical for cell survival. In all three domains of life, bacteria, archaea, and eukaryotes, initiator proteins bind replication origins in an ATP-dependent manner, play critical roles in replisome assembly, and coordinate cell-cycle regulation. We discuss how the eukaryotic initiator, Origin recognition complex (ORC), coordinates different events during the cell cycle. We propose that ORC is the maestro driving the orchestra to coordinately perform the musical pieces of replication, chromatin organization, and repair.
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Affiliation(s)
- Dazhen Liu
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801 USA
| | - Jay Sonalkar
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801 USA
| | - Supriya G. Prasanth
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, 601S Goodwin Avenue, Urbana, IL 61801 USA
- Cancer center at Illinois, UIUC
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10
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Peng Z, Wu Y, Wang J, Gu S, Wang Y, Xue B, Fu P, Xiang W. Development and validation of a glioma-associated mesenchymal stem cell-related gene prognostic index for predicting prognosis and guiding individualized therapy in glioma. Stem Cell Res Ther 2023; 14:56. [PMID: 37005685 PMCID: PMC10068170 DOI: 10.1186/s13287-023-03285-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 03/14/2023] [Indexed: 04/04/2023] Open
Abstract
BACKGROUND Recent studies have demonstrated that glioma-associated mesenchymal stem cells (GA-MSCs) are implicated in the regulation of glioma malignant progression. However, the prognostic value of GA-MSCs has not been comprehensively explored in glioma. METHODS We extracted GA-MSCs from glioma tissues, established intracranial xenograft models in nude mice, and obtained GA-MSC-related genes (GA-MSCRGs) by using microarrays. The transcriptome data and clinical information of glioma patients were obtained from the CGGA and TCGA databases. We screened 8 prognostic GA-MSCRGs to construct a prognostic index by using the multivariate Cox regression method. The validity of the GA-MSCRGPI was verified in the training (CGGA693) and validation (TCGA and CGGA325) cohorts. The expression patterns of these 8 GA-MSCRGs were validated in 78 glioma tissue specimens by using a qRT‒PCR assay. RESULTS GA-MSCs were successfully isolated from glioma tissues. Based on intracranial xenograft models and transcriptome microarray screening, 8 genes (MCM7, CDK6, ORC1, CCL20, TNFRSF12A, POLA1, TRAF1 and TIAM1) were selected for the construction of a GA-MSC-related gene prognostic index (GA-MSCRGPI). In both the training and validation cohorts, high GA-MSCRGPI patients showed an inferior survival outcome compared with low GA-MSCRGPI patients. A nomogram was established based on independent prognostic indicators (age, WHO grade and GA-MSCRGPI) and exhibited a strong forecasting ability for overall survival (OS). Moreover, we found that the GA-MSCRGPI could evaluate the prognosis of glioma patients undergoing chemoradiotherapy. The high GA-MSCRGPI group exhibited higher immune, stromal and ESTIMATE scores; lower tumor purity; higher infiltration of Tregs and M2-type macrophages; fewer activated NK cells; and higher expression of immune checkpoints. Tumor Immune Dysfunction and Exclusion (TIDE) showed that the high GA-MSCRGPI group had more responders to ICI therapy. The results of the genetic mutation profile and tumor mutation burden (TMB) in different GA-MSCRGPI subgroups further supplement GA-MSCRGPI-related mechanisms. Finally, the expression patterns of 8 selected GA-MSCRGs in GA-MSCRGPI were correlated with glioma WHO grades to a certain extent. CONCLUSION The constructed GA-MSCRGPI could predict prognosis and guide individualized therapy in glioma patients.
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Affiliation(s)
- Zesheng Peng
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yuxi Wu
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jiajing Wang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Sujie Gu
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yihao Wang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Bingzhou Xue
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Peng Fu
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
| | - Wei Xiang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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11
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Nucleosome-directed replication origin licensing independent of a consensus DNA sequence. Nat Commun 2022; 13:4947. [PMID: 35999198 PMCID: PMC9399094 DOI: 10.1038/s41467-022-32657-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/09/2022] [Indexed: 02/08/2023] Open
Abstract
The numerous enzymes and cofactors involved in eukaryotic DNA replication are conserved from yeast to human, and the budding yeast Saccharomyces cerevisiae (S.c.) has been a useful model organism for these studies. However, there is a gap in our knowledge of why replication origins in higher eukaryotes do not use a consensus DNA sequence as found in S.c. Using in vitro reconstitution and single-molecule visualization, we show here that S.c. origin recognition complex (ORC) stably binds nucleosomes and that ORC-nucleosome complexes have the intrinsic ability to load the replicative helicase MCM double hexamers onto adjacent nucleosome-free DNA regardless of sequence. Furthermore, we find that Xenopus laevis nucleosomes can substitute for yeast ones in engaging with ORC. Combined with re-analyses of genome-wide ORC binding data, our results lead us to propose that the yeast origin recognition machinery contains the cryptic capacity to bind nucleosomes near a nucleosome-free region and license origins, and that this nucleosome-directed origin licensing paradigm generalizes to all eukaryotes. Most eukaryotes do not use a consensus DNA sequence as binding sites for the origin recognition complex (ORC) to initiate DNA replication, however budding yeast do. Here the authors show S. cerevisiae ORC can bind nucleosomes near nucleosome-free regions and recruit replicative helicases to form a pre-replication complex independent of the DNA sequence.
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12
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Ma N, Liu H, Wu Y, Yao M, Zhang B. Inhibition of N-Acetyltransferase 10 Suppresses the Progression of Prostate Cancer through Regulation of DNA Replication. Int J Mol Sci 2022; 23:ijms23126573. [PMID: 35743017 PMCID: PMC9223896 DOI: 10.3390/ijms23126573] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/06/2022] [Accepted: 06/10/2022] [Indexed: 11/16/2022] Open
Abstract
Cancer suppression through the inhibition of N-acetyltransferase 10 (NAT10) by its specific inhibitor Remodelin has been demonstrated in a variety of human cancers. Here, we report the inhibitory effects of Remodelin on prostate cancer (PCa) cells and the possible associated mechanisms. The prostate cancer cell lines VCaP, LNCaP, PC3, and DU145 were used. The in vitro proliferation, migration, and invasion of cells were measured by a cell proliferation assay, colony formation, wound healing, and Transwell assays, respectively. In vivo tumor growth was analyzed by transplantation into nude mice. The inhibition of NAT10 by Remodelin not only suppressed growth, migration, and invasion in vitro, but also the in vivo cancer growth of prostate cancer cells. The involvement of NAT10 in DNA replication was assessed by EdU labeling, DNA spreading, iPOND, and ChIP-PCR assays. The inhibition of NAT10 by Remodelin slowed DNA replication. NAT10 was detected in the prereplication complex, and it could also bind to DNA replication origins. Furthermore, the interaction between NAT10 and CDC6 was analyzed by Co-IP. The altered expression of NAT10 was measured by immunofluorescence staining and Western blotting. Remodelin markedly reduced the levels of CDC6 and AR. The expression of NAT10 could be altered under either castration or noncastration conditions, and Remodelin still suppressed the growth of in vitro-induced castration-resistant prostate cancers. The analysis of a TCGA database revealed that the overexpression of NAT10, CDC6, and MCM7 in prostate cancers were correlated with the Gleason score and node metastasis. Our data demonstrated that Remodelin, an inhibitor of NAT10, effectively inhibits the growth of prostate cancer cells under either no castration or castration conditions, likely by impairing DNA replication.
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Affiliation(s)
| | | | | | | | - Bo Zhang
- Correspondence: ; Tel.: +86-10-82802627
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13
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Symbiosis with Dinoflagellates Alters Cnidarian Cell-Cycle Gene Expression. Cell Microbiol 2022. [DOI: 10.1155/2022/3330160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In the cnidarian-dinoflagellate symbiosis, hosts show altered expression of genes involved in growth and proliferation when in the symbiotic state, but little is known about the molecular mechanisms that underlie the host’s altered growth rate. Using tissue-specific transcriptomics, we determined how symbiosis affects expression of cell cycle-associated genes, in the model symbiotic cnidarian Exaiptasia diaphana (Aiptasia). The presence of symbionts within the gastrodermis elicited cell-cycle arrest in the G1 phase in a larger proportion of host cells compared with the aposymbiotic gastrodermis. The symbiotic gastrodermis also showed a reduction in the amount of cells synthesizing their DNA and progressing through mitosis when compared with the aposymbiotic gastrodermis. Host apoptotic inhibitors (Mdm2) were elevated, while host apoptotic sensitizers (c-Myc) were depressed, in the symbiotic gastrodermis when compared with the aposymbiotic gastrodermis and epidermis of symbiotic anemones, respectively. This indicates that the presence of symbionts negatively regulates host apoptosis, possibly contributing to their persistence within the host. Transcripts (ATM/ATR) associated with DNA damage were also downregulated in symbiotic gastrodermal tissues. In epidermal cells, a single gene (Mob1) required for mitotic completion was upregulated in symbiotic compared with aposymbiotic anemones, suggesting that the presence of symbionts in the gastrodermis stimulates host cell division in the epidermis. To further corroborate this hypothesis, we performed microscopic analysis using an S-phase indicator (EdU), allowing us to evaluate cell cycling in host cells. Our results confirmed that there were significantly more proliferating host cells in both the gastrodermis and epidermis in the symbiotic state compared with the aposymbiotic state. Furthermore, when comparing between tissue layers in the presence of symbionts, the epidermis had significantly more proliferating host cells than the symbiont-containing gastrodermis. These results contribute to our understanding of the influence of symbionts on the mechanisms of cnidarian cell proliferation and mechanisms associated with symbiont maintenance.
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14
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Kothapalli R, Ghirlando R, Khan ZA, Chatterjee S, Kedei N, Chattoraj D. The dimerization interface of initiator RctB governs chaperone and enhancer dependence of Vibrio cholerae chromosome 2 replication. Nucleic Acids Res 2022; 50:4529-4544. [PMID: 35390166 PMCID: PMC9071482 DOI: 10.1093/nar/gkac210] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 03/01/2022] [Accepted: 03/20/2022] [Indexed: 11/13/2022] Open
Abstract
Protein function often requires remodeling of protein structure. In the well-studied iteron-containing plasmids, the initiator of replication has a dimerization interface that undergoes chaperone-mediated remodeling. This remodeling reduces dimerization and promotes DNA replication, since only monomers bind origin DNA. A structurally homologs interface exists in RctB, the replication initiator of Vibrio cholerae chromosome 2 (Chr2). Chaperones also promote Chr2 replication, although both monomers and dimers of RctB bind to origin, and chaperones increase the binding of both. Here we report how five changes in the dimerization interface of RctB affect the protein. The mutants are variously defective in dimerization, more active as initiator, and except in one case, unresponsive to chaperone (DnaJ). The results indicate that chaperones also reduce RctB dimerization and support the proposal that the paradoxical chaperone-promoted dimer binding likely represents sequential binding of monomers on DNA. RctB is also activated for replication initiation upon binding to a DNA site, crtS, and three of the mutants are also unresponsive to crtS. This suggests that crtS, like chaperones, reduces dimerization, but additional evidence suggests that the remodelling activities function independently. Involvement of two remodelers in reducing dimerization signifies the importance of dimerization in limiting Chr2 replication.
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Affiliation(s)
- Roopa Kothapalli
- Basic Research Laboratory, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, NIDDK, NIH, Bethesda, MD 20892, USA
| | - Zaki Ali Khan
- Basic Research Laboratory, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Soniya Chatterjee
- Basic Research Laboratory, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Noemi Kedei
- Collaborative Protein Technology Resource, OSTP, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
| | - Dhruba K Chattoraj
- Basic Research Laboratory, Center for Cancer Research, NCI, NIH, Bethesda, MD 20892, USA
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15
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Padmanabhan S, Sanyal K, Dubey D. Identification and in silico analysis of the origin recognition complex in the human fungal pathogen Candida albicans. MICROPUBLICATION BIOLOGY 2021; 2021:10.17912/micropub.biology.000465. [PMID: 34568775 PMCID: PMC8456302 DOI: 10.17912/micropub.biology.000465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 09/08/2021] [Accepted: 09/08/2021] [Indexed: 11/06/2022]
Abstract
DNA replication in eukaryotes is initiated by the orchestrated assembly and association of initiator proteins (heterohexameric Origin Recognition Complex, ORC) on the replication origins. These functionally conserved proteins play significant roles in diverse cellular processes besides their central role in ignition of DNA replication at origins. Candida albicans, a major human fungal pathogen, is a diploid budding yeast that belongs to Ascomycota. However, C. albicans is significantly diverged from a well-studied model organism Saccharomyces cerevisiae, another ascomycete. The components of the DNA replication machinery in C. albicans remain largely uncharacterized. Identification of factors required for DNA replication is essential for understanding the evolution of the DNA replication machinery. We identified the putative ORC homologs in C. albicans and determined their relatedness with those of other eukaryotes including several yeast species. Our extensive in silico studies demonstrate that the domain architecture of CaORC proteins share similarities with the ORC proteins of S. cerevisiae. We dissect the domain organization of ORC (trans-acting factors) subunits that seem to associate with DNA replication origins in C. albicans. We present a model of the 3D structure of CaORC4 to gain further insights of this protein's function.
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Affiliation(s)
- Sreedevi Padmanabhan
- Molecular Biology Laboratory, Veer Bahadur Singh Purvanchal University, Jaunpur- 222003, Uttar Pradesh, India
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, JNCASR, Bangalore - 560064, India.,
Correspondence to: Kaustuv Sanyal (); Dharanidhar Dubey ()
| | - Dharanidhar Dubey
- Molecular Biology Laboratory, Veer Bahadur Singh Purvanchal University, Jaunpur- 222003, Uttar Pradesh, India.,
Correspondence to: Kaustuv Sanyal (); Dharanidhar Dubey ()
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16
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The structure of ORC-Cdc6 on an origin DNA reveals the mechanism of ORC activation by the replication initiator Cdc6. Nat Commun 2021; 12:3883. [PMID: 34162887 PMCID: PMC8222357 DOI: 10.1038/s41467-021-24199-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 06/07/2021] [Indexed: 01/31/2023] Open
Abstract
The Origin Recognition Complex (ORC) binds to sites in chromosomes to specify the location of origins of DNA replication. The S. cerevisiae ORC binds to specific DNA sequences throughout the cell cycle but becomes active only when it binds to the replication initiator Cdc6. It has been unclear at the molecular level how Cdc6 activates ORC, converting it to an active recruiter of the Mcm2-7 hexamer, the core of the replicative helicase. Here we report the cryo-EM structure at 3.3 Å resolution of the yeast ORC–Cdc6 bound to an 85-bp ARS1 origin DNA. The structure reveals that Cdc6 contributes to origin DNA recognition via its winged helix domain (WHD) and its initiator-specific motif. Cdc6 binding rearranges a short α-helix in the Orc1 AAA+ domain and the Orc2 WHD, leading to the activation of the Cdc6 ATPase and the formation of the three sites for the recruitment of Mcm2-7, none of which are present in ORC alone. The results illuminate the molecular mechanism of a critical biochemical step in the licensing of eukaryotic replication origins. Eukaryotic DNA replication is mediated by many proteins which are tightly regulated for an efficient firing of replication at each cell cycle. Here the authors report a cryo-EM structure of the yeast ORC–Cdc6 bound to an 85-bp ARS1 origin DNA revealing additional insights into how Cdc6 contributes to origin DNA recognition.
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17
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The extrachromosomal elements of the Naegleria genus: How little we know. Plasmid 2021; 115:102567. [PMID: 33617907 DOI: 10.1016/j.plasmid.2021.102567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 02/05/2021] [Accepted: 02/10/2021] [Indexed: 11/20/2022]
Abstract
There are currently 47 characterized species in the Naegleria genus of free-living amoebae. Each amoeba has thousands of extrachromosomal elements that are closed circular structures comprised of a single ribosomal DNA (rDNA) copy and a large non-rDNA sequence. Despite the presence of putative open reading frames and introns, ribosomal RNA is the only established transcript. A single origin of DNA replication (ori) has been mapped within the non-rDNA sequence for one species (N. gruberi), a finding that strongly indicates that these episomes replicate independently of the cell's chromosomal DNA component. This article reviews that which has been published about these interesting DNA elements and by analyzing available sequence data, discusses the possibility that different phylogenetically related clusters of Naegleria species individually conserve ori structures and suggests where the rRNA promoter and termination sites may be located.
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18
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Prospect of reprogramming replication licensing for cancer drug development. Biomed Pharmacother 2021; 136:111190. [PMID: 33497909 DOI: 10.1016/j.biopha.2020.111190] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/15/2020] [Accepted: 12/26/2020] [Indexed: 12/15/2022] Open
Abstract
Eukaryotic chromosomal DNA replication is preceded by replication licensing which involves the identification of the origin of replication by origin recognition complex (ORC). The ORC loads pre-replication complexes (pre-RCs) through a series of tightly regulated mechanisms where the ORC interacts with Cdc6 to recruit cdt1-MCM2-7 complexes to the origin of replication. In eukaryotes, adherence to regulatory mechanisms of the replication program is required to ensure that all daughter cells carry the exact copy of genetic material as the parent cell. Failure of which leads to the development of genome instability syndromes like cancer, diabetes, etc. In an event of such occurrence, preventing cells from carrying the defaulted genetic material and passing it to other cells hinges on the regulation of chromosomal DNA replication. Thus, understanding the mechanisms underpinning chromosomal DNA replication and particularly replication licensing can expose druggable enzymes, effector molecules, and secondary messengers that can be targeted for diagnosis and therapeutic purposes. Effectively drugging these molecular markers to reprogram pre-replication events can be used to control the fate of chromosomal DNA replication for the treatment of genome instability disorders and in this case, cancer. This review discusses available knowledge of replication licensing in the contest of molecular drug discovery for the treatment of cancer.
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Ocaña-Pallarès E, Vergara Z, Desvoyes B, Tejada-Jimenez M, Romero-Jurado A, Galván A, Fernández E, Ruiz-Trillo I, Gutierrez C. Origin Recognition Complex (ORC) Evolution Is Influenced by Global Gene Duplication/Loss Patterns in Eukaryotic Genomes. Genome Biol Evol 2020; 12:3878-3889. [PMID: 31990293 PMCID: PMC7058166 DOI: 10.1093/gbe/evaa011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2020] [Indexed: 12/29/2022] Open
Abstract
The conservation of orthologs of most subunits of the origin recognition complex (ORC) has served to propose that the whole complex is common to all eukaryotes. However, various uncertainties have arisen concerning ORC subunit composition in a variety of lineages. Also, it is unclear whether the ancestral diversification of ORC in eukaryotes was accompanied by the neofunctionalization of some subunits, for example, role of ORC1 in centriole homeostasis. We have addressed these questions by reconstructing the distribution and evolutionary history of ORC1-5/CDC6 in a taxon-rich eukaryotic data set. First, we identified ORC subunits previously undetected in divergent lineages, which allowed us to propose a series of parsimonious scenarios for the origin of this multiprotein complex. Contrary to previous expectations, we found a global tendency in eukaryotes to increase or decrease the number of subunits as a consequence of genome duplications or streamlining, respectively. Interestingly, parasites show significantly lower number of subunits than free-living eukaryotes, especially those with the lowest genome size and gene content metrics. We also investigated the evolutionary origin of the ORC1 role in centriole homeostasis mediated by the PACT region in human cells. In particular, we tested the consequences of reducing ORC1 levels in the centriole-containing green alga Chlamydomonas reinhardtii. We found that the proportion of centrioles to flagella and nuclei was not dramatically affected. This, together with the PACT region not being significantly more conserved in centriole-bearing eukaryotes, supports the notion that this neofunctionalization of ORC1 would be a recent acquisition rather than an ancestral eukaryotic feature.
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Affiliation(s)
| | - Zaida Vergara
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, Madrid, Spain
| | - Bénédicte Desvoyes
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, Madrid, Spain
| | - Manuel Tejada-Jimenez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Córdoba, Córdoba, Spain
| | - Ainoa Romero-Jurado
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Córdoba, Córdoba, Spain
| | - Aurora Galván
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Córdoba, Córdoba, Spain
| | - Emilio Fernández
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Córdoba, Córdoba, Spain
| | - Iñaki Ruiz-Trillo
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Barcelona, Spain.,Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain.,ICREA, Barcelona, Spain
| | - Crisanto Gutierrez
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, Madrid, Spain
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20
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Balasov M, Akhmetova K, Chesnokov I. Humanized Drosophila Model of the Meier-Gorlin Syndrome Reveals Conserved and Divergent Features of the Orc6 Protein. Genetics 2020; 216:995-1007. [PMID: 33037049 PMCID: PMC7768257 DOI: 10.1534/genetics.120.303698] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/06/2020] [Indexed: 11/18/2022] Open
Abstract
Meier-Gorlin syndrome (MGS) is a rare, autosomal recessive disorder characterized by microtia, primordial dwarfism, small ears, and skeletal abnormalities. Patients with MGS often carry mutations in genes encoding the subunits of the Origin Recognition Complex (ORC), components of the prereplicative complex and replication machinery. Orc6 is an important component of ORC and has functions in both DNA replication and cytokinesis. A mutation in the conserved C-terminal motif of Orc6 associated with MGS impedes the interaction of Orc6 with core ORC. Recently, a new mutation in Orc6 was also identified; however, it is localized in the N-terminal domain of the protein. To study the functions of Orc6, we used the human gene to rescue the orc6 deletion in Drosophila Using this "humanized" Orc6-based Drosophila model of MGS, we discovered that unlike the previous Y225S MGS mutation in Orc6, the K23E substitution in the N-terminal TFIIB-like domain of Orc6 disrupts the protein ability to bind DNA. Our studies revealed the importance of evolutionarily conserved and variable domains of Orc6 protein, and allowed the studies of human protein functions and the analysis of the critical amino acids in live animal heterologous system, as well as provided novel insights into the mechanisms underlying MGS pathology.
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Affiliation(s)
- Maxim Balasov
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Alabama at Birmingham, Alabama 35294
| | - Katarina Akhmetova
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Alabama at Birmingham, Alabama 35294
| | - Igor Chesnokov
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Alabama at Birmingham, Alabama 35294
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Cheng J, Li N, Wang X, Hu J, Zhai Y, Gao N. Structural insight into the assembly and conformational activation of human origin recognition complex. Cell Discov 2020; 6:88. [PMID: 33298899 PMCID: PMC7684300 DOI: 10.1038/s41421-020-00232-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/22/2020] [Indexed: 12/15/2022] Open
Abstract
The function of the origin recognition complex (ORC) in DNA replication is highly conserved in recognizing and marking the initiation sites. The detailed molecular mechanisms by which human ORC is reconfigured into a state competent for origin association remain largely unknown. Here, we present structural characterizations of human ORC1–5 and ORC2–5 assemblies. ORC2–5 exhibits a tightly autoinhibited conformation with the winged-helix domain of ORC2 completely blocking the central DNA-binding channel. The binding of ORC1 partially relieves the autoinhibitory effect of ORC2–5 through remodeling ORC2-WHD, which makes ORC2-WHD away from the central channel creating a still autoinhibited but more dynamic structure. In particular, the AAA+ domain of ORC1 is highly flexible to sample a variety of conformations from inactive to potentially active states. These results provide insights into the detailed mechanisms regulating the autoinhibition of human ORC and its subsequent activation for DNA binding.
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Affiliation(s)
- Jiaxuan Cheng
- State Key Laboratory of Membrane Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.,State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China.
| | - Xiaohan Wang
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Jiazhi Hu
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing 100871, China.
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22
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Xu N, You Y, Liu C, Balasov M, Lun LT, Geng Y, Fung CP, Miao H, Tian H, Choy TT, Shi X, Fan Z, Zhou B, Akhmetova K, Din RU, Yang H, Hao Q, Qian P, Chesnokov I, Zhu G. Structural basis of DNA replication origin recognition by human Orc6 protein binding with DNA. Nucleic Acids Res 2020; 48:11146-11161. [PMID: 32986843 PMCID: PMC7641730 DOI: 10.1093/nar/gkaa751] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 08/18/2020] [Accepted: 09/19/2020] [Indexed: 01/08/2023] Open
Abstract
The six-subunit origin recognition complex (ORC), a DNA replication initiator, defines the localization of the origins of replication in eukaryotes. The Orc6 subunit is the smallest and the least conserved among ORC subunits. It is required for DNA replication and essential for viability in all species. Orc6 in metazoans carries a structural homology with transcription factor TFIIB and can bind DNA on its own. Here, we report a solution structure of the full-length human Orc6 (HsOrc6) alone and in a complex with DNA. We further showed that human Orc6 is composed of three independent domains: N-terminal, middle and C-terminal (HsOrc6-N, HsOrc6-M and HsOrc6-C). We also identified a distinct DNA-binding domain of human Orc6, named as HsOrc6-DBD. The detailed analysis of the structure revealed novel amino acid clusters important for the interaction with DNA. Alterations of these amino acids abolish DNA-binding ability of Orc6 and result in reduced levels of DNA replication. We propose that Orc6 is a DNA-binding subunit of human/metazoan ORC and may play roles in targeting, positioning and assembling the functional ORC at the origins.
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Affiliation(s)
- Naining Xu
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
- Department of Oral and Maxillofacial Surgery, Peking University ShenzhenHospital, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen, 518036, China
| | - Yingying You
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
- Department of Oncology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Changdong Liu
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Maxim Balasov
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Lee Tung Lun
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Yanyan Geng
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Chun Po Fung
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Haitao Miao
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Honglei Tian
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - To To Choy
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Xiao Shi
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Zhuming Fan
- School of Biomedical Sciences, University of Hong Kong, 21 Sassoon Road, Hong Kong SAR, 00000, China
| | - Bo Zhou
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Katarina Akhmetova
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Rahman Ud Din
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Hongyu Yang
- Department of Oral and Maxillofacial Surgery, Peking University Shenzhen Hospital, Shenzhen Peking University, Shenzhen, 518036, China
| | - Quan Hao
- School of Biomedical Sciences, University of Hong Kong, 21 Sassoon Road, Hong Kong SAR, 00000, China
| | - Peiyuan Qian
- Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
| | - Igor Chesnokov
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Guang Zhu
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
- State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, 00000, China
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23
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Csibra E, Renders M, Pinheiro VB. Bacterial Cell Display as a Robust and Versatile Platform for Engineering Low-Affinity Ligands and Enzymes. Chembiochem 2020; 21:2844-2853. [PMID: 32413179 PMCID: PMC7586821 DOI: 10.1002/cbic.202000203] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/11/2020] [Indexed: 12/31/2022]
Abstract
Directed evolution has been remarkably successful at expanding the chemical and functional boundaries of biology. That progress is heavily dependent on the robustness and flexibility of the available selection platforms, given the significant cost to (re)develop a given platform to target a new desired function. Bacterial cell display has a significant track record as a viable strategy for the engineering of mesophilic enzymes, as enzyme activity can be probed directly and free from interference from the cellular milieu, but its adoption has lagged behind other display-based methods. Herein, we report the development of SNAP as a quantitative reporter for bacterial cell display, which enables fast troubleshooting and the systematic development of the display-based selection platform, thus improving its robustness. In addition, we demonstrate that even weak interactions between displayed proteins and nucleic acids can be harnessed for the specific labelling of bacterial cells, allowing functional characterisation of DNA binding proteins and enzymes, thus making it a highly flexible platform for these biochemical functions. Together, this establishes bacterial display as a robust and flexible platform, ideally suited for the systematic engineering of ligands and enzymes needed for XNA molecular biology.
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Affiliation(s)
- Eszter Csibra
- University College LondonDepartment of Structural and Molecular BiologyGower StreetLondonWC1E 6BTUK
- Current address: Imperial College LondonExhibition RoadLondonSW7 2AZUK
| | - Marleen Renders
- Rega Institute for Medical ResearchKU LeuvenHerestraat, 49 box 10413000LeuvenBelgium
- Current address: Touchlight Genetics Ltd. Morelands & Riverdale BuildingsLower Sunbury RoadHamptonTW12 2ERUK
| | - Vitor B. Pinheiro
- University College LondonDepartment of Structural and Molecular BiologyGower StreetLondonWC1E 6BTUK
- Rega Institute for Medical ResearchKU LeuvenHerestraat, 49 box 10413000LeuvenBelgium
- Institute of Structural and Molecular BiologyBirkbeck CollegeUniversity of LondonMalet StreetLondonWC1E 7HXUK
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24
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Damasceno JD, Marques CA, Black J, Briggs E, McCulloch R. Read, Write, Adapt: Challenges and Opportunities during Kinetoplastid Genome Replication. Trends Genet 2020; 37:21-34. [PMID: 32993968 PMCID: PMC9213392 DOI: 10.1016/j.tig.2020.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/31/2020] [Accepted: 09/01/2020] [Indexed: 12/31/2022]
Abstract
The genomes of all organisms are read throughout their growth and development, generating new copies during cell division and encoding the cellular activities dictated by the genome’s content. However, genomes are not invariant information stores but are purposefully altered in minor and major ways, adapting cellular behaviour and driving evolution. Kinetoplastids are eukaryotic microbes that display a wide range of such read–write genome activities, in many cases affecting critical aspects of their biology, such as host adaptation. Here we discuss the range of read–write genome changes found in two well-studied kinetoplastid parasites, Trypanosoma brucei and Leishmania, focusing on recent work that suggests such adaptive genome variation is linked to novel strategies the parasites use to replicate their unconventional genomes. Polycistronic transcription dominates and shapes kinetoplastid genomes, inevitably leading to clashes with DNA replication. By harnessing the resultant DNA damage for adaptation, kinetoplastids have huge potential for dynamic read–write genome variation. Major origins of DNA replication are confined to the boundaries of polycistronic transcription units in the Trypanosoma brucei and Leishmania genomes, putatively limiting DNA damage. Subtelomeres may lack this arrangement, generating read–write hotspots. In T. brucei, early replication of the highly transcribed subtelomeric variant surface glycoprotein (VSG) expression site may ensure replication-transcription clashes within this site to trigger DNA recombination, an event critical for antigenic variation. Leishmania genomes show extensive aneuploidy and copy number variation. Notably, DNA replication requires recombination factors and relies on post-S phase replication of subtelomeres. Evolution of compartmentalised DNA replication programmes underpin important aspects of genome biology in kinetoplastids, illustrating the consolidation of genome maintenance strategies to promote genome plasticity.
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Affiliation(s)
- Jeziel D Damasceno
- The Wellcome Centre for Integrative Parasitology, University of Glasgow, Institute of Infection, Immunity and Inflammation, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK.
| | - Catarina A Marques
- The Wellcome Centre for Integrative Parasitology, University of Glasgow, Institute of Infection, Immunity and Inflammation, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Jennifer Black
- The Wellcome Centre for Integrative Parasitology, University of Glasgow, Institute of Infection, Immunity and Inflammation, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Emma Briggs
- The Wellcome Centre for Integrative Parasitology, University of Glasgow, Institute of Infection, Immunity and Inflammation, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK; Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Richard McCulloch
- The Wellcome Centre for Integrative Parasitology, University of Glasgow, Institute of Infection, Immunity and Inflammation, Sir Graeme Davies Building, 120 University Place, Glasgow, G12 8TA, UK.
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25
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Structural mechanism for replication origin binding and remodeling by a metazoan origin recognition complex and its co-loader Cdc6. Nat Commun 2020; 11:4263. [PMID: 32848132 PMCID: PMC7450096 DOI: 10.1038/s41467-020-18067-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/03/2020] [Indexed: 12/11/2022] Open
Abstract
Eukaryotic DNA replication initiation relies on the origin recognition complex (ORC), a DNA-binding ATPase that loads the Mcm2–7 replicative helicase onto replication origins. Here, we report cryo-electron microscopy (cryo-EM) structures of DNA-bound Drosophila ORC with and without the co-loader Cdc6. These structures reveal that Orc1 and Orc4 constitute the primary DNA binding site in the ORC ring and cooperate with the winged-helix domains to stabilize DNA bending. A loop region near the catalytic Walker B motif of Orc1 directly contacts DNA, allosterically coupling DNA binding to ORC’s ATPase site. Correlating structural and biochemical data show that DNA sequence modulates DNA binding and remodeling by ORC, and that DNA bending promotes Mcm2–7 loading in vitro. Together, these findings explain the distinct DNA sequence-dependencies of metazoan and S. cerevisiae initiators in origin recognition and support a model in which DNA geometry and bendability contribute to Mcm2–7 loading site selection in metazoans. The origin recognition complex (ORC) is essential for loading the Mcm2–7 replicative helicase onto DNA during DNA replication initiation. Here, the authors describe several cryo-electron microscopy structures of Drosophila ORC bound to DNA and its cofactor Cdc6 and also report an in vitro reconstitution system for Drosophila Mcm2–7 loading, revealing unexpected features of ORC’s DNA binding and remodeling mechanism during Mcm2–7 loading.
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26
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Abstract
The loading of the core Mcm2-7 helicase onto origin DNA is essential for the formation of replication forks and genomic stability. Here, we report two cryo-electron microscopy (cryo-EM) structures that capture helicase loader–helicase complexes just prior to DNA insertion. These pre-loading structures, combined with a computational simulation of the dynamic transition from the pre-loading state to the loaded state, provide crucial insights into the mechanism required for topologically linking the helicase to DNA. The helicase loading system is highly conserved from yeast to human, which means that the molecular principles described here for the yeast system are likely applicable to the human system. DNA replication origins serve as sites of replicative helicase loading. In all eukaryotes, the six-subunit origin recognition complex (Orc1-6; ORC) recognizes the replication origin. During late M-phase of the cell-cycle, Cdc6 binds to ORC and the ORC–Cdc6 complex loads in a multistep reaction and, with the help of Cdt1, the core Mcm2-7 helicase onto DNA. A key intermediate is the ORC–Cdc6–Cdt1–Mcm2-7 (OCCM) complex in which DNA has been already inserted into the central channel of Mcm2-7. Until now, it has been unclear how the origin DNA is guided by ORC–Cdc6 and inserted into the Mcm2-7 hexamer. Here, we truncated the C-terminal winged-helix-domain (WHD) of Mcm6 to slow down the loading reaction, thereby capturing two loading intermediates prior to DNA insertion in budding yeast. In “semi-attached OCCM,” the Mcm3 and Mcm7 WHDs latch onto ORC–Cdc6 while the main body of the Mcm2-7 hexamer is not connected. In “pre-insertion OCCM,” the main body of Mcm2-7 docks onto ORC–Cdc6, and the origin DNA is bent and positioned adjacent to the open DNA entry gate, poised for insertion, at the Mcm2–Mcm5 interface. We used molecular simulations to reveal the dynamic transition from preloading conformers to the loaded conformers in which the loading of Mcm2-7 on DNA is complete and the DNA entry gate is fully closed. Our work provides multiple molecular insights into a key event of eukaryotic DNA replication.
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27
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Butenko A, Opperdoes FR, Flegontova O, Horák A, Hampl V, Keeling P, Gawryluk RMR, Tikhonenkov D, Flegontov P, Lukeš J. Evolution of metabolic capabilities and molecular features of diplonemids, kinetoplastids, and euglenids. BMC Biol 2020; 18:23. [PMID: 32122335 PMCID: PMC7052976 DOI: 10.1186/s12915-020-0754-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/17/2020] [Indexed: 12/24/2022] Open
Abstract
Background The Euglenozoa are a protist group with an especially rich history of evolutionary diversity. They include diplonemids, representing arguably the most species-rich clade of marine planktonic eukaryotes; trypanosomatids, which are notorious parasites of medical and veterinary importance; and free-living euglenids. These different lifestyles, and particularly the transition from free-living to parasitic, likely require different metabolic capabilities. We carried out a comparative genomic analysis across euglenozoan diversity to see how changing repertoires of enzymes and structural features correspond to major changes in lifestyles. Results We find a gradual loss of genes encoding enzymes in the evolution of kinetoplastids, rather than a sudden decrease in metabolic capabilities corresponding to the origin of parasitism, while diplonemids and euglenids maintain more metabolic versatility. Distinctive characteristics of molecular machines such as kinetochores and the pre-replication complex that were previously considered specific to parasitic kinetoplastids were also identified in their free-living relatives. Therefore, we argue that they represent an ancestral rather than a derived state, as thought until the present. We also found evidence of ancient redundancy in systems such as NADPH-dependent thiol-redox. Only the genus Euglena possesses the combination of trypanothione-, glutathione-, and thioredoxin-based systems supposedly present in the euglenozoan common ancestor, while other representatives of the phylum have lost one or two of these systems. Lastly, we identified convergent losses of specific metabolic capabilities between free-living kinetoplastids and ciliates. Although this observation requires further examination, it suggests that certain eukaryotic lineages are predisposed to such convergent losses of key enzymes or whole pathways. Conclusions The loss of metabolic capabilities might not be associated with the switch to parasitic lifestyle in kinetoplastids, and the presence of a highly divergent (or unconventional) kinetochore machinery might not be restricted to this protist group. The data derived from the transcriptomes of free-living early branching prokinetoplastids suggests that the pre-replication complex of Trypanosomatidae is a highly divergent version of the conventional machinery. Our findings shed light on trends in the evolution of metabolism in protists in general and open multiple avenues for future research.
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Affiliation(s)
- Anzhelika Butenko
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Fred R Opperdoes
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Olga Flegontova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Aleš Horák
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Vladimír Hampl
- Faculty of Science, Charles University, Biocev, Vestec, Czech Republic
| | - Patrick Keeling
- Department of Botany, University of British Columbia, Vancouver, Canada
| | | | - Denis Tikhonenkov
- Department of Botany, University of British Columbia, Vancouver, Canada.,Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Russia
| | - Pavel Flegontov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic. .,Faculty of Science, University of Ostrava, Ostrava, Czech Republic. .,Present address: Department of Genetics, Harvard Medical School, Boston, USA.
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic. .,Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic.
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28
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Bleichert F. Mechanisms of replication origin licensing: a structural perspective. Curr Opin Struct Biol 2019; 59:195-204. [PMID: 31630057 DOI: 10.1016/j.sbi.2019.08.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 08/26/2019] [Accepted: 08/29/2019] [Indexed: 12/24/2022]
Abstract
The duplication of chromosomal DNA is a key cell cycle event that involves the controlled, bidirectional assembly of the replicative machinery. In a tightly regulated, multi-step reaction, replicative helicases and other components of the DNA synthesis apparatus are recruited to replication start sites. Although the molecular approaches for assembling this machinery vary between the different domains of life, a common theme revolves around the use of ATP-dependent initiation factors to recognize and remodel origins and to load replicative helicases in a bidirectional manner onto DNA. This review summarizes recent advances in understanding the mechanisms of replication initiation in eukaryotes, focusing on how the replicative helicase is loaded in this system.
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29
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Leonard AC, Rao P, Kadam RP, Grimwade JE. Changing Perspectives on the Role of DnaA-ATP in Orisome Function and Timing Regulation. Front Microbiol 2019; 10:2009. [PMID: 31555240 PMCID: PMC6727663 DOI: 10.3389/fmicb.2019.02009] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 08/16/2019] [Indexed: 01/20/2023] Open
Abstract
Bacteria, like all cells, must precisely duplicate their genomes before they divide. Regulation of this critical process focuses on forming a pre-replicative nucleoprotein complex, termed the orisome. Orisomes perform two essential mechanical tasks that configure the unique chromosomal replication origin, oriC to start a new round of chromosome replication: (1) unwinding origin DNA and (2) assisting with loading of the replicative DNA helicase on exposed single strands. In Escherichia coli, a necessary orisome component is the ATP-bound form of the bacterial initiator protein, DnaA. DnaA-ATP differs from DnaA-ADP in its ability to oligomerize into helical filaments, and in its ability to access a subset of low affinity recognition sites in the E. coli replication origin. The helical filaments have been proposed to play a role in both of the key mechanical tasks, but recent studies raise new questions about whether they are mandatory for orisome activity. It was recently shown that a version of E. coli oriC (oriCallADP), whose multiple low affinity DnaA recognition sites bind DnaA-ATP and DnaA-ADP similarly, was fully occupied and unwound by DnaA-ADP in vitro, and in vivo suppressed the lethality of DnaA mutants defective in ATP binding and ATP-specific oligomerization. However, despite their functional equivalency, orisomes assembled on oriCallADP were unable to trigger chromosome replication at the correct cell cycle time and displayed a hyper-initiation phenotype. Here we present a new perspective on DnaA-ATP, and suggest that in E. coli, DnaA-ATP is not required for mechanical functions, but rather is needed for site recognition and occupation, so that initiation timing is coupled to DnaA-ATP levels. We also discuss how other bacterial types may utilize DnaA-ATP and DnaA-ADP, and whether the high diversity of replication origins in the bacterial world reflects different regulatory strategies for how DnaA-ATP is used to control orisome assembly.
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Affiliation(s)
- Alan C Leonard
- Laboratory of Microbial Genetics, Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, Melbourne, FL, United States
| | - Prassanna Rao
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Rohit P Kadam
- Laboratory of Microbial Genetics, Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, Melbourne, FL, United States
| | - Julia E Grimwade
- Laboratory of Microbial Genetics, Department of Biomedical and Chemical Engineering and Science, Florida Institute of Technology, Melbourne, FL, United States
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30
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Trojani A, Pungolino E, Dal Molin A, Lodola M, Rossi G, D’Adda M, Perego A, Elena C, Turrini M, Borin L, Bucelli C, Malato S, Carraro MC, Spina F, Latargia ML, Artale S, Spedini P, Anghilieri M, Di Camillo B, Baruzzo G, De Canal G, Iurlo A, Morra E, Cairoli R. Nilotinib interferes with cell cycle, ABC transporters and JAK-STAT signaling pathway in CD34+/lin- cells of patients with chronic phase chronic myeloid leukemia after 12 months of treatment. PLoS One 2019; 14:e0218444. [PMID: 31318870 PMCID: PMC6638825 DOI: 10.1371/journal.pone.0218444] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 06/03/2019] [Indexed: 01/05/2023] Open
Abstract
Chronic myeloid leukemia (CML) is characterized by the constitutive tyrosine kinase activity of the oncoprotein BCR-ABL1 in myeloid progenitor cells that activates multiple signal transduction pathways leading to the leukemic phenotype. The tyrosine-kinase inhibitor (TKI) nilotinib inhibits the tyrosine kinase activity of BCR-ABL1 in CML patients. Despite the success of nilotinib treatment in patients with chronic-phase (CP) CML, a population of Philadelphia-positive (Ph+) quiescent stem cells escapes the drug activity and can lead to drug resistance. The molecular mechanism by which these quiescent cells remain insensitive is poorly understood. The aim of this study was to compare the gene expression profiling (GEP) of bone marrow (BM) CD34+/lin- cells from CP-CML patients at diagnosis and after 12 months of nilotinib treatment by microarray, in order to identify gene expression changes and the dysregulation of pathways due to nilotinib action. We selected BM CD34+/lin- cells from 78 CP-CML patients at diagnosis and after 12 months of first-line nilotinib therapy and microarray analysis was performed. GEP bioinformatic analyses identified 2,959 differently expressed probes and functional clustering determined some significantly enriched pathways between diagnosis and 12 months of nilotinib treatment. Among these pathways, we observed the under expression of 26 genes encoding proteins belonging to the cell cycle after 12 months of nilotinib treatment which led to the up-regulation of chromosome replication, cell proliferation, DNA replication, and DNA damage checkpoint at diagnosis. We demonstrated the under expression of the ATP-binding cassette (ABC) transporters ABCC4, ABCC5, and ABCD3 encoding proteins which pumped drugs out of the cells after 12 months of nilotinib. Moreover, GEP data demonstrated the deregulation of genes involved in the JAK-STAT signaling pathway. The down-regulation of JAK2, IL7, STAM, PIK3CA, PTPN11, RAF1, and SOS1 key genes after 12 months of nilotinib could demonstrate the up-regulation of cell cycle, proliferation and differentiation via MAPK and PI3K-AKT signaling pathways at diagnosis.
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Affiliation(s)
- Alessandra Trojani
- Division of Hematology, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
- * E-mail:
| | - Ester Pungolino
- Division of Hematology, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | | | - Milena Lodola
- Division of Hematology, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Giuseppe Rossi
- Department of Hematology, ASST Spedali Civili, Brescia, Italy
| | - Mariella D’Adda
- Department of Hematology, ASST Spedali Civili, Brescia, Italy
| | | | - Chiara Elena
- Hematology Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Mauro Turrini
- Division of Hematology, Department of Internal Medicine, Valduce Hospital, Como, Italy
| | - Lorenza Borin
- Hematology Division, San Gerardo Hospital, Monza, Italy
| | - Cristina Bucelli
- Hematology Division, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Simona Malato
- Hematology and Bone Marrow Transplantation Unit, San Raffaele Scientific Institute, Milano, Italy
| | | | - Francesco Spina
- Division of Hematology–Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy
| | | | | | | | | | - Barbara Di Camillo
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Giacomo Baruzzo
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Gabriella De Canal
- Pathology Department, Cytogenetics, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
| | - Alessandra Iurlo
- Hematology Division, Foundation IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milano, Italy
| | - Enrica Morra
- Executive Committee, Rete Ematologia Lombarda, Italy
| | - Roberto Cairoli
- Division of Hematology, ASST Grande Ospedale Metropolitano Niguarda, Milano, Italy
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Kawakami H, Muraoka R, Ohashi E, Kawabata K, Kanamoto S, Chichibu T, Tsurimoto T, Katayama T. Specific basic patch-dependent multimerization of Saccharomyces cerevisiae ORC on single-stranded DNA promotes ATP hydrolysis. Genes Cells 2019; 24:608-618. [PMID: 31233675 DOI: 10.1111/gtc.12710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/12/2019] [Accepted: 06/18/2019] [Indexed: 11/26/2022]
Abstract
Replication initiation at specific genomic loci dictates precise duplication and inheritance of genetic information. In eukaryotic cells, ATP-bound origin recognition complexes (ORCs) stably bind to double-stranded (ds) DNA origins to recruit the replicative helicase onto the origin DNA. To achieve these processes, an essential region of the origin DNA must be recognized by the eukaryotic origin sensor (EOS) basic patch within the disordered domain of the largest ORC subunit, Orc1. Although ORC also binds single-stranded (ss) DNA in an EOS-independent manner, it is unknown whether EOS regulates ORC on ssDNA. We found that, in budding yeast, ORC multimerizes on ssDNA in vitro independently of adenine nucleotides. We also found that the ORC multimers form in an EOS-dependent manner and stimulate the ORC ATPase activity. An analysis of genomics data supported the idea that ORC-ssDNA binding occurs in vivo at specific genomic loci outside of replication origins. These results suggest that EOS function is differentiated by ORC-bound ssDNA, which promotes ORC self-assembly and ATP hydrolysis. These mechanisms could modulate ORC activity at specific genomic loci and could be conserved among eukaryotes.
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Affiliation(s)
- Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Ryuya Muraoka
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Eiji Ohashi
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Kenta Kawabata
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Shota Kanamoto
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Takeaki Chichibu
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshiki Tsurimoto
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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Structure and function of the Orc1 BAH-nucleosome complex. Nat Commun 2019; 10:2894. [PMID: 31263106 PMCID: PMC6602975 DOI: 10.1038/s41467-019-10609-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/14/2019] [Indexed: 12/03/2022] Open
Abstract
The Origin Recognition Complex (ORC) is essential for replication, heterochromatin formation, telomere maintenance and genome stability in eukaryotes. Here we present the structure of the yeast Orc1 BAH domain bound to the nucleosome core particle. Our data reveal that Orc1, unlike its close homolog Sir3 involved in gene silencing, does not appear to discriminate between acetylated and non-acetylated lysine 16, modification states of the histone H4 tail that specify open and closed chromatin respectively. We elucidate the mechanism for this unique feature of Orc1 and hypothesize that its ability to interact with nucleosomes regardless of K16 modification state enables it to perform critical functions in both hetero- and euchromatin. We also show that direct interactions with nucleosomes are essential for Orc1 to maintain the integrity of rDNA borders during meiosis, a process distinct and independent from its known roles in silencing and replication. The Origin Recognition Complex (ORC) plays conserved and diverse roles in eukaryotes. Here the authors present the structure of a chromatin interacting domain of yeast Orc1 in complex with the nucleosome core particle, revealing that Orc1 interacts with the histone H4 tail irrespective of K16 acetylation; a modification that regulates accessibility to chromatin.
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33
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Barton JK, Silva RMB, O'Brien E. Redox Chemistry in the Genome: Emergence of the [4Fe4S] Cofactor in Repair and Replication. Annu Rev Biochem 2019; 88:163-190. [PMID: 31220976 PMCID: PMC6590699 DOI: 10.1146/annurev-biochem-013118-110644] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many DNA-processing enzymes have been shown to contain a [4Fe4S] cluster, a common redox cofactor in biology. Using DNA electrochemistry, we find that binding of the DNA polyanion promotes a negative shift in [4Fe4S] cluster potential, which corresponds thermodynamically to a ∼500-fold increase in DNA-binding affinity for the oxidized [4Fe4S]3+ cluster versus the reduced [4Fe4S]2+ cluster. This redox switch can be activated from a distance using DNA charge transport (DNA CT) chemistry. DNA-processing proteins containing the [4Fe4S] cluster are enumerated, with possible roles for the redox switch highlighted. A model is described where repair proteins may signal one another using DNA-mediated charge transport as a first step in their search for lesions. The redox switch in eukaryotic DNA primases appears to regulate polymerase handoff, and in DNA polymerase δ, the redox switch provides a means to modulate replication in response to oxidative stress. We thus describe redox signaling interactions of DNA-processing [4Fe4S] enzymes, as well as the most interesting potential players to consider in delineating new DNA-mediated redox signaling networks.
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Affiliation(s)
- Jacqueline K Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA;
| | - Rebekah M B Silva
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA;
| | - Elizabeth O'Brien
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA;
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34
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Polyploidy in halophilic archaea: regulation, evolutionary advantages, and gene conversion. Biochem Soc Trans 2019; 47:933-944. [PMID: 31189733 DOI: 10.1042/bst20190256] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 12/20/2022]
Abstract
All analyzed haloarachea are polyploid. In addition, haloarchaea contain more than one type of chromosome, and thus the gene dosage can be regulated independently on different replicons. Haloarchaea and several additional archaea have more than one replication origin on their major chromosome, in stark contrast with bacteria, which have a single replication origin. Two of these replication origins of Haloferax volcanii have been studied in detail and turned out to have very different properties. The chromosome copy number appears to be regulated in response to growth phases and environmental factors. Archaea typically contain about two Origin Recognition Complex (ORC) proteins, which are homologous to eukaryotic ORC proteins. However, haloarchaea are the only archaeal group that contains a multitude of ORC proteins. All 16 ORC protein paralogs from H. volcanii are involved in chromosome copy number regulation. Polyploidy has many evolutionary advantages for haloarchaea, e.g. a high resistance to desiccation, survival over geological times, and the relaxation of cell cycle-specific replication control. A further advantage is the ability to grow in the absence of external phosphate while using the many genome copies as internal phosphate storage polymers. Very efficient gene conversion operates in haloarchaea and results in the unification of genome copies. Taken together, haloarchaea are excellent models to study many aspects of genome biology in prokaryotes, exhibiting properties that have not been found in bacteria.
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35
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Nguyen H, Ward WS, James NG. Spatial and temporal resolution of mORC4 fluorescent variants reveals structural requirements for achieving higher order self-association and pronuclei entry. Methods Appl Fluoresc 2019; 7:035002. [PMID: 30865939 PMCID: PMC6636821 DOI: 10.1088/2050-6120/ab0f57] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The Origin Replication Complex (ORC), which is a multi-subunit protein complex composed of six proteins ORC1-6, is essential for initiating licensing at DNA replication origins. We have previously reported that ORC4 has an alternative function wherein it forms a cage surrounding the extruded chromatin in female meiosis and is required for polar body extrusion (PBE). As this is a highly unexpected finding for protein that normally binds DNA, we tested whether ORC4 can actually form larger, higher order structures, which would be necessary to form a cage-like structure. We generated two fluorescent constructs of mouse ORC4, mORC4-EGFP and mORC4-FlAsH, to examine its spatial dynamics during oocyte activation in live cells. We show that both constructs were primarily monomeric throughout the embryo but self-association into larger units was detected with both probes. However, mORC4-FlAsH clearly showed higher order self-association and unique spatial distribution while mORC4-EGFP failed to form large structures during Anaphase II. Interestingly, both variants were found in the pronuclei suggesting that its role in DNA licensing is still functional. Our results with both constructs support the prediction that ORC4 can form higher order structures in the cytoplasm, suggesting that it is possible to form a cage-like structure. The finding that FlAsH labeled ORC4 formed demonstrably larger higher order structures than ORC4-GFP suggests that ORC4 oligomerization is sensitive to the bulky addition of GFP at its carboxy terminus.
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Affiliation(s)
- Hieu Nguyen
- Department of Anatomy, Biochemistry, and Physiology, John A. Burns School of Medicine, 1960 East-West Rd., University of Hawaii, Honolulu, HI 96822, United States of America
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36
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Characterization of Pch2 localization determinants reveals a nucleolar-independent role in the meiotic recombination checkpoint. Chromosoma 2019; 128:297-316. [PMID: 30859296 DOI: 10.1007/s00412-019-00696-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 02/05/2019] [Accepted: 02/20/2019] [Indexed: 10/27/2022]
Abstract
The meiotic recombination checkpoint blocks meiotic cell cycle progression in response to synapsis and/or recombination defects to prevent aberrant chromosome segregation. The evolutionarily conserved budding yeast Pch2TRIP13 AAA+ ATPase participates in this pathway by supporting phosphorylation of the Hop1HORMAD adaptor at T318. In the wild type, Pch2 localizes to synapsed chromosomes and to the unsynapsed rDNA region (nucleolus), excluding Hop1. In contrast, in synaptonemal complex (SC)-defective zip1Δ mutants, which undergo checkpoint activation, Pch2 is detected only on the nucleolus. Alterations in some epigenetic marks that lead to Pch2 dispersion from the nucleolus suppress zip1Δ-induced checkpoint arrest. These observations have led to the notion that Pch2 nucleolar localization could be important for the meiotic recombination checkpoint. Here we investigate how Pch2 chromosomal distribution impacts checkpoint function. We have generated and characterized several mutations that alter Pch2 localization pattern resulting in aberrant Hop1 distribution and compromised meiotic checkpoint response. Besides the AAA+ signature, we have identified a basic motif in the extended N-terminal domain critical for Pch2's checkpoint function and localization. We have also examined the functional relevance of the described Orc1-Pch2 interaction. Both proteins colocalize in the rDNA, and Orc1 depletion during meiotic prophase prevents Pch2 targeting to the rDNA allowing unwanted Hop1 accumulation on this region. However, Pch2 association with SC components remains intact in the absence of Orc1. We finally show that checkpoint activation is not affected by the lack of Orc1 demonstrating that, in contrast to previous hypotheses, nucleolar localization of Pch2 is actually dispensable for the meiotic checkpoint.
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37
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Influence of Origin Recognition Complex Proteins on the Copy Numbers of Three Chromosomes in Haloferax volcanii. J Bacteriol 2018; 200:JB.00161-18. [PMID: 29941422 DOI: 10.1128/jb.00161-18] [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: 03/16/2018] [Accepted: 06/17/2018] [Indexed: 12/22/2022] Open
Abstract
Replication initiation in archaea involves a protein named ORC, Cdc6, or ORC1/Cdc6, which is homologous to the eukaryotic origin recognition complex (ORC) proteins and to the eukaryotic Cdc6. Archaeal replication origins are comprised of origin repeat regions and adjacent orc genes. Some archaea contain a single replication origin and a single orc gene, while others have more than one of each. Haloferax volcanii is exceptional because it contains, in total, six replication origins on three chromosomes and 16 orc genes. Phylogenetic trees were constructed that showed that orc gene duplications occurred at very different times in evolution. To unravel the influence of the ORC proteins on chromosome copy number and cellular fitness, it was attempted to generate deletion mutants of all 16 genes. A total of 12 single-gene deletion mutants could be generated, and only three orc gene turned out to be essential. For one gene, the deletion analysis failed. Growth analyses revealed that no deletion mutant had a growth defect, but some had a slight growth advantage compared to the wild type. Quantification of the chromosome copy numbers in the deletion mutants showed that all 12 ORC proteins influenced the copy numbers of one, two, or all three chromosomes. The lack of an ORC led to an increase or decrease of chromosome copy number. Therefore, chromosome copy numbers in Hfxvolcanii are regulated by an intricate network of ORC proteins. This is in contrast to other archaea, in which ORC proteins typically bind specifically to the adjacent origin.IMPORTANCE The core origins of archaea are comprised of a repeat region and an adjacent gene for an origin recognition complex (ORC) protein, which is homologous to eukaryotic ORC proteins. Haloferax volcanii is exceptional because it contains six replication origins on three chromosomes and an additional 10 orc genes that are not adjacent to an origin. This unique ORC protein repertoire was used to unravel the importance of core origin orc genes and of origin-remote orc genes. Remarkably, all ORC proteins influenced the copy number of at least one chromosome. Some of them influenced those of all three chromosomes, showing that cross-regulation in trans exists in Hfx. volcanii Furthermore, the evolution of the archaeal ORC protein family was analyzed.
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The Temporal Regulation of S Phase Proteins During G 1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1042:335-369. [PMID: 29357066 DOI: 10.1007/978-981-10-6955-0_16] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Successful DNA replication requires intimate coordination with cell-cycle progression. Prior to DNA replication initiation in S phase, a series of essential preparatory events in G1 phase ensures timely, complete, and precise genome duplication. Among the essential molecular processes are regulated transcriptional upregulation of genes that encode replication proteins, appropriate post-transcriptional control of replication factor abundance and activity, and assembly of DNA-loaded protein complexes to license replication origins. In this chapter we describe these critical G1 events necessary for DNA replication and their regulation in the context of both cell-cycle entry and cell-cycle progression.
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39
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Structure of the origin recognition complex bound to DNA replication origin. Nature 2018; 559:217-222. [DOI: 10.1038/s41586-018-0293-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 05/08/2018] [Indexed: 11/09/2022]
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40
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Conformational control and DNA-binding mechanism of the metazoan origin recognition complex. Proc Natl Acad Sci U S A 2018; 115:E5906-E5915. [PMID: 29899147 DOI: 10.1073/pnas.1806315115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In eukaryotes, the heterohexameric origin recognition complex (ORC) coordinates replication onset by facilitating the recruitment and loading of the minichromosome maintenance 2-7 (Mcm2-7) replicative helicase onto DNA to license origins. Drosophila ORC can adopt an autoinhibited configuration that is predicted to prevent Mcm2-7 loading; how the complex is activated and whether other ORC homologs can assume this state are not known. Using chemical cross-linking and mass spectrometry, biochemical assays, and electron microscopy (EM), we show that the autoinhibited state of Drosophila ORC is populated in solution, and that human ORC can also adopt this form. ATP binding to ORC supports a transition from the autoinhibited state to an active configuration, enabling the nucleotide-dependent association of ORC with both DNA and Cdc6. An unstructured N-terminal region adjacent to the conserved ATPase domain of Orc1 is shown to be required for high-affinity ORC-DNA interactions, but not for activation. ORC optimally binds DNA duplexes longer than the predicted footprint of the ORC ATPases associated with a variety of cellular activities (AAA+) and winged-helix (WH) folds; cryo-EM analysis of Drosophila ORC bound to DNA and Cdc6 indicates that ORC contacts DNA outside of its central core region, bending the DNA away from its central DNA-binding channel. Our findings indicate that ORC autoinhibition may be common to metazoans and that ORC-Cdc6 remodels origin DNA before Mcm2-7 recruitment and loading.
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41
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Marques CA, McCulloch R. Conservation and Variation in Strategies for DNA Replication of Kinetoplastid Nuclear Genomes. Curr Genomics 2018; 19:98-109. [PMID: 29491738 PMCID: PMC5814967 DOI: 10.2174/1389202918666170815144627] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/19/2017] [Accepted: 04/11/2017] [Indexed: 12/21/2022] Open
Abstract
Introduction: Understanding how the nuclear genome of kinetoplastid parasites is replicated received experimental stimulus from sequencing of the Leishmania major, Trypanosoma brucei and Trypanosoma cruzi genomes around 10 years ago. Gene annotations suggested key players in DNA replication initiation could not be found in these organisms, despite considerable conservation amongst characterised eukaryotes. Initial studies that indicated trypanosomatids might possess an archaeal-like Origin Recognition Complex (ORC), composed of only a single factor termed ORC1/CDC6, have been supplanted by the more recent identification of an ORC in T. brucei. However, the constituent subunits of T. brucei ORC are highly diverged relative to other eukaryotic ORCs and the activity of the complex appears subject to novel, positive regulation. The availability of whole genome sequences has also allowed the deployment of genome-wide strategies to map DNA replication dynamics, to date in T. brucei and Leishmania. ORC1/CDC6 binding and function in T. brucei displays pronounced overlap with the unconventional organisation of gene expression in the genome. Moreover, mapping of sites of replication initiation suggests pronounced differences in replication dynamics in Leishmania relative to T. brucei. Conclusion: Here we discuss what implications these emerging data may have for parasite and eukaryotic biology of DNA replication.
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Affiliation(s)
- Catarina A Marques
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, Dow Street, University of Dundee, Dundee, DD1 5EH, UK
| | - Richard McCulloch
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, Sir Graeme Davis Building, 120 University Place, University of Glasgow, Glasgow, G12 8TA, UK
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42
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Structure and mechanism of plant histone mark readers. SCIENCE CHINA-LIFE SCIENCES 2017; 61:170-177. [PMID: 29019143 DOI: 10.1007/s11427-017-9163-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 08/11/2017] [Indexed: 10/18/2022]
Abstract
In eukaryotes, epigenetic-based mechanisms are involved in almost all the important biological processes. Amongst different epigenetic regulation pathways, the dynamic covalent modifications on histones are the most extensively investigated and characterized types. The covalent modifications on histone can be "read" by specific protein domains and then subsequently trigger downstream signaling events. Plants generally possess epigenetic regulation systems similar to animals and fungi, but also exhibit some plant-specific features. Similar to animals and fungi, plants require distinct protein domains to specifically "read" modified histones in both modification-specific and sequence-specific manners. In this review, we will focus on recent progress of the structural studies on the recognition of the epigenetic marks on histones by plant reader proteins, and further summarize the general and exceptional features of plant histone mark readers.
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43
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Orlova N, Gerding M, Ivashkiv O, Olinares PDB, Chait BT, Waldor MK, Jeruzalmi D. The replication initiator of the cholera pathogen's second chromosome shows structural similarity to plasmid initiators. Nucleic Acids Res 2017; 45:3724-3737. [PMID: 28031373 PMCID: PMC5397143 DOI: 10.1093/nar/gkw1288] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/18/2016] [Indexed: 01/23/2023] Open
Abstract
The conserved DnaA-oriC system is used to initiate replication of primary chromosomes throughout the bacterial kingdom; however, bacteria with multipartite genomes evolved distinct systems to initiate replication of secondary chromosomes. In the cholera pathogen, Vibrio cholerae, and in related species, secondary chromosome replication requires the RctB initiator protein. Here, we show that RctB consists of four domains. The structure of its central two domains resembles that of several plasmid replication initiators. RctB contains at least three DNA binding winged-helix-turn-helix motifs, and mutations within any of these severely compromise biological activity. In the structure, RctB adopts a head-to-head dimeric configuration that likely reflects the arrangement in solution. Therefore, major structural reorganization likely accompanies complex formation on the head-to-tail array of binding sites in oriCII. Our findings support the hypothesis that the second Vibrionaceae chromosome arose from an ancestral plasmid, and that RctB may have evolved additional regulatory features.
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Affiliation(s)
- Natalia Orlova
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA.,Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, NY 10016, USA
| | - Matthew Gerding
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.,Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Olha Ivashkiv
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA
| | - Paul Dominic B Olinares
- Laboratory for Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, NY 10021, USA
| | - Brian T Chait
- Laboratory for Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, NY 10021, USA
| | - Matthew K Waldor
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.,Division of Infectious Diseases, Brigham and Women's Hospital, Boston, MA, USA.,Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - David Jeruzalmi
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA.,Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, NY 10016, USA.,Ph.D. Program in Biology, The Graduate Center of the City University of New York, NY 10016, USA.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, NY 10016, USA
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44
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Hernández-Pérez S, Cabrera E, Salido E, Lim M, Reid L, Lakhani SR, Khanna KK, Saunus JM, Freire R. DUB3 and USP7 de-ubiquitinating enzymes control replication inhibitor Geminin: molecular characterization and associations with breast cancer. Oncogene 2017; 36:4802-4809. [PMID: 28288134 DOI: 10.1038/onc.2017.21] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/15/2016] [Accepted: 01/02/2017] [Indexed: 12/11/2022]
Abstract
Correct control of DNA replication is crucial to maintain genomic stability in dividing cells. Inappropriate re-licensing of replicated origins is associated with chromosomal instability (CIN), a hallmark of cancer progression that at the same time provides potential opportunities for therapeutic intervention. Geminin is a critical inhibitor of the DNA replication licensing factor Cdt1. To properly achieve its functions, Geminin levels are tightly regulated through the cell cycle by ubiquitin-dependent proteasomal degradation, but the de-ubiquitinating enzymes (DUBs) involved had not been identified. Here we report that DUB3 and USP7 control human Geminin. Overexpression of either DUB3 or USP7 increases Geminin levels through reduced ubiquitination. Conversely, depletion of DUB3 or USP7 reduces Geminin levels, and DUB3 knockdown increases re-replication events, analogous to the effect of Geminin depletion. In exploring potential clinical implications, we found that USP7 and Geminin are strongly correlated in a cohort of invasive breast cancers (P<1.01E-08). As expected, Geminin expression is highly prognostic. Interestingly, we found a non-monotonic relationship between USP7 and breast cancer-specific survival, with both very low or high levels of USP7 associated with poor outcome, independent of estrogen receptor status. Altogether, our data identify DUB3 and USP7 as factors that regulate DNA replication by controlling Geminin protein stability, and suggest that USP7 may be involved in Geminin dysregulation during breast cancer progression.
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Affiliation(s)
- S Hernández-Pérez
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, La Laguna, Spain
| | - E Cabrera
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, La Laguna, Spain
| | - E Salido
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, La Laguna, Spain
| | - M Lim
- The University of Queensland, UQ Centre for Clinical Research, Herston, QLD, Australia.,QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - L Reid
- The University of Queensland, UQ Centre for Clinical Research, Herston, QLD, Australia.,QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - S R Lakhani
- The University of Queensland, UQ Centre for Clinical Research, Herston, QLD, Australia.,Pathology Queensland, The Royal Brisbane and Women's Hospital, Herston, QLD, Australia.,The University of Queensland, School of Medicine, Herston, QLD, Australia
| | - K K Khanna
- Signal Transduction Laboratory, QIMR Berghofer Institute of Medical Research, Brisbane, QLD, Australia
| | - J M Saunus
- The University of Queensland, UQ Centre for Clinical Research, Herston, QLD, Australia.,QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - R Freire
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, La Laguna, Spain
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45
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Uzcanga G, Lara E, Gutiérrez F, Beaty D, Beske T, Teran R, Navarro JC, Pasero P, Benítez W, Poveda A. Nuclear DNA replication and repair in parasites of the genus Leishmania: Exploiting differences to develop innovative therapeutic approaches. Crit Rev Microbiol 2016; 43:156-177. [PMID: 27960617 DOI: 10.1080/1040841x.2016.1188758] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Leishmaniasis is a common tropical disease that affects mainly poor people in underdeveloped and developing countries. This largely neglected infection is caused by Leishmania spp, a parasite from the Trypanosomatidae family. This parasitic disease has different clinical manifestations, ranging from localized cutaneous to more harmful visceral forms. The main limitations of the current treatments are their high cost, toxicity, lack of specificity, and long duration. Efforts to improve treatments are necessary to deal with this infectious disease. Many approved drugs to combat diseases as diverse as cancer, bacterial, or viral infections take advantage of specific features of the causing agent or of the disease. Recent evidence indicates that the specific characteristics of the Trypanosomatidae replication and repair machineries could be used as possible targets for the development of new treatments. Here, we review in detail the molecular mechanisms of DNA replication and repair regulation in trypanosomatids of the genus Leishmania and the drugs that could be useful against this disease.
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Affiliation(s)
- Graciela Uzcanga
- a Centro Internacional de Zoonosis, Facultad de Ciencias Químicas, Facultad de Medicina Veterinaria , Universidad Central del Ecuador , Quito , Ecuador.,b Programa Prometeo , SENESCYT, Whymper E7-37 y Alpallana, Quito , Ecuador.,c Facultad de Ciencias Naturales y Ambientales, Universidad Internacional SEK Calle Alberto Einstein sn y 5ta transversal , Quito , Ecuador.,d Fundación Instituto de Estudios Avanzados-IDEA , Caracas , Venezuela
| | - Eliana Lara
- a Centro Internacional de Zoonosis, Facultad de Ciencias Químicas, Facultad de Medicina Veterinaria , Universidad Central del Ecuador , Quito , Ecuador.,e Institute of Human Genetics , CNRS UPR 1142, 141 rue de la Cardonille, Equipe Labellisée Ligue Contre le Cancer , Montpellier cedex 5 , France
| | - Fernanda Gutiérrez
- a Centro Internacional de Zoonosis, Facultad de Ciencias Químicas, Facultad de Medicina Veterinaria , Universidad Central del Ecuador , Quito , Ecuador
| | - Doyle Beaty
- a Centro Internacional de Zoonosis, Facultad de Ciencias Químicas, Facultad de Medicina Veterinaria , Universidad Central del Ecuador , Quito , Ecuador
| | - Timo Beske
- a Centro Internacional de Zoonosis, Facultad de Ciencias Químicas, Facultad de Medicina Veterinaria , Universidad Central del Ecuador , Quito , Ecuador
| | - Rommy Teran
- a Centro Internacional de Zoonosis, Facultad de Ciencias Químicas, Facultad de Medicina Veterinaria , Universidad Central del Ecuador , Quito , Ecuador
| | - Juan-Carlos Navarro
- a Centro Internacional de Zoonosis, Facultad de Ciencias Químicas, Facultad de Medicina Veterinaria , Universidad Central del Ecuador , Quito , Ecuador.,f Universidad Central de Venezuela, Instituto de Zoología y Ecología Tropical , Caracas , Venezuela.,g Facultad de Ciencias Naturales y Ambientales, Universidad Internacional SEK, Calle Alberto Einstein sn y 5ta transversal , Quito , Ecuador
| | - Philippe Pasero
- e Institute of Human Genetics , CNRS UPR 1142, 141 rue de la Cardonille, Equipe Labellisée Ligue Contre le Cancer , Montpellier cedex 5 , France
| | - Washington Benítez
- a Centro Internacional de Zoonosis, Facultad de Ciencias Químicas, Facultad de Medicina Veterinaria , Universidad Central del Ecuador , Quito , Ecuador
| | - Ana Poveda
- a Centro Internacional de Zoonosis, Facultad de Ciencias Químicas, Facultad de Medicina Veterinaria , Universidad Central del Ecuador , Quito , Ecuador
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Massey AJ. Tumour growth environment modulates Chk1 signalling pathways and Chk1 inhibitor sensitivity. Sci Rep 2016; 6:35874. [PMID: 27775084 PMCID: PMC5075878 DOI: 10.1038/srep35874] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 10/07/2016] [Indexed: 01/13/2023] Open
Abstract
Clinical development of Chk1 inhibitors is currently focussed on evaluating activity as monotherapy and as potentiators of chemotherapy. To aid translation of pre-clinical studies, we sought to understand the effects of the tumour growth environment on Chk1 signalling and sensitivity to small molecule Chk1 inhibition. Spheroid culture altered Chk1 signalling to a more xenograft like state but decreased sensitivity to Chk1 inhibition. Growth in low serum did not alter DDR signalling but increased the sensitivity of A2058 and U2OS tumour cells to Chk1 inhibition. An analysis of the expression levels of replication associated proteins identified a correlation between Cdc6 and pChk1 (S296) as well as total Chk1 in xenograft derived samples and between Cdc6 and total Chk1 in anchorage-dependent growth derived protein samples. No apparent correlation between Chk1 or Cdc6 expression and sensitivity to Chk1 inhibition in vitro was observed. A database analysis revealed upregulation of CDC6 mRNA expression in tumour compared to normal tissue and a correlation between CDC6 and CHEK1 mRNA expression in human cancers. We suggest that Cdc6 overexpression in human tumours requires a concomitant increase in Chk1 to counterbalance the deleterious effects of origin hyperactivation-induced DNA damage.
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Kawakami H, Ohashi E, Tsurimoto T, Katayama T. Rapid Purification and Characterization of Mutant Origin Recognition Complexes in Saccharomyces cerevisiae. Front Microbiol 2016; 7:521. [PMID: 27148210 PMCID: PMC4834435 DOI: 10.3389/fmicb.2016.00521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/29/2016] [Indexed: 11/25/2022] Open
Abstract
Purification of the origin recognition complex (ORC) from wild-type budding yeast cells more than two decades ago opened up doors to analyze the initiation of eukaryotic chromosomal DNA replication biochemically. Although revised methods to purify ORC from overproducing cells were reported later, purification of mutant proteins using these systems still depends on time-consuming processes including genetic manipulation to construct and amplify mutant baculoviruses or yeast strains as well as several canonical protein fractionations. Here, we present a streamlined method to construct mutant overproducers, followed by purification of mutant ORCs. Use of mammalian cells co-transfected with conveniently mutagenized plasmids bearing a His tag excludes many of the construction and fractionation steps. Transfection is highly efficient. All the six subunits of ORC are overexpressed at a considerable level and isolated as a functional heterohexameric complex. Furthermore, use of mammalian cells prevents contamination of wild-type ORC from yeast cells. The method is applicable to wild-type and at least three mutant ORCs, and the resultant purified complexes show expected biochemical activities. The rapid acquisition of mutant ORCs using this system will boost systematic biochemical dissection of ORC and can be even applied to the purification of protein complexes other than ORC.
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Affiliation(s)
- Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University Fukuoka, Japan
| | - Eiji Ohashi
- Department of Biology, Faculty of Science, Kyushu University Fukuoka, Japan
| | - Toshiki Tsurimoto
- Department of Biology, Faculty of Science, Kyushu University Fukuoka, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University Fukuoka, Japan
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Marques CA, Tiengwe C, Lemgruber L, Damasceno JD, Scott A, Paape D, Marcello L, McCulloch R. Diverged composition and regulation of the Trypanosoma brucei origin recognition complex that mediates DNA replication initiation. Nucleic Acids Res 2016; 44:4763-84. [PMID: 26951375 PMCID: PMC4889932 DOI: 10.1093/nar/gkw147] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/01/2016] [Indexed: 01/14/2023] Open
Abstract
Initiation of DNA replication depends upon recognition of genomic sites, termed origins, by AAA+ ATPases. In prokaryotes a single factor binds each origin, whereas in eukaryotes this role is played by a six-protein origin recognition complex (ORC). Why eukaryotes evolved a multisubunit initiator, and the roles of each component, remains unclear. In Trypanosoma brucei, an ancient unicellular eukaryote, only one ORC-related initiator, TbORC1/CDC6, has been identified by sequence homology. Here we show that three TbORC1/CDC6-interacting factors also act in T. brucei nuclear DNA replication and demonstrate that TbORC1/CDC6 interacts in a high molecular complex in which a diverged Orc4 homologue and one replicative helicase subunit can also be found. Analysing the subcellular localization of four TbORC1/CDC6-interacting factors during the cell cycle reveals that one factor, TbORC1B, is not a static constituent of ORC but displays S-phase restricted nuclear localization and expression, suggesting it positively regulates replication. This work shows that ORC architecture and regulation are diverged features of DNA replication initiation in T. brucei, providing new insight into this key stage of eukaryotic genome copying.
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Affiliation(s)
- Catarina A Marques
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Calvin Tiengwe
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Leandro Lemgruber
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Jeziel D Damasceno
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Alan Scott
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Daniel Paape
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Lucio Marcello
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Richard McCulloch
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
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49
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Patel DJ. A Structural Perspective on Readout of Epigenetic Histone and DNA Methylation Marks. Cold Spring Harb Perspect Biol 2016; 8:a018754. [PMID: 26931326 DOI: 10.1101/cshperspect.a018754] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This article outlines the protein modules that target methylated lysine histone marks and 5mC DNA marks, and the molecular principles underlying recognition. The article focuses on the structural basis underlying readout of isolated marks by single reader molecules, as well as multivalent readout of multiple marks by linked reader cassettes at the histone tail and nucleosome level. Additional topics addressed include the role of histone mimics, cross talk between histone marks, technological developments at the genome-wide level, advances using chemical biology approaches, the linkage between histone and DNA methylation, the role for regulatory lncRNAs, and the promise of chromatin-based therapeutic modalities.
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Affiliation(s)
- Dinshaw J Patel
- Structural Biology Department, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
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50
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Abstract
Protein phosphatase 2A (PP2A) plays a critical multi-faceted role in the regulation of the cell cycle. It is known to dephosphorylate over 300 substrates involved in the cell cycle, regulating almost all major pathways and cell cycle checkpoints. PP2A is involved in such diverse processes by the formation of structurally distinct families of holoenzymes, which are regulated spatially and temporally by specific regulators. Here, we review the involvement of PP2A in the regulation of three cell signaling pathways: wnt, mTOR and MAP kinase, as well as the G1→S transition, DNA synthesis and mitotic initiation. These processes are all crucial for proper cell survival and proliferation and are often deregulated in cancer and other diseases.
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Affiliation(s)
- Nathan Wlodarchak
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
| | - Yongna Xing
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
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