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Edri T, Cohen D, Shabtai Y, Fainsod A. Alcohol induces neural tube defects by reducing retinoic acid signaling and promoting neural plate expansion. Front Cell Dev Biol 2023; 11:1282273. [PMID: 38116205 PMCID: PMC10728305 DOI: 10.3389/fcell.2023.1282273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/22/2023] [Indexed: 12/21/2023] Open
Abstract
Introduction: Neural tube defects (NTDs) are among the most debilitating and common developmental defects in humans. The induction of NTDs has been attributed to abnormal folic acid (vitamin B9) metabolism, Wnt and BMP signaling, excess retinoic acid (RA), dietary components, environmental factors, and many others. In the present study we show that reduced RA signaling, including alcohol exposure, induces NTDs. Methods: Xenopus embryos were exposed to pharmacological RA biosynthesis inhibitors to study the induction of NTDs. Embryos were treated with DEAB, citral, or ethanol, all of which inhibit the biosynthesis of RA, or injected to overexpress Cyp26a1 to reduce RA. NTD induction was studied using neural plate and notochord markers together with morphological analysis. Expression of the neuroectodermal regulatory network and cell proliferation were analyzed to understand the morphological malformations of the neural plate. Results: Reducing RA signaling levels using retinaldehyde dehydrogenase inhibitors (ethanol, DEAB, and citral) or Cyp26a1-driven degradation efficiently induce NTDs. These NTDs can be rescued by providing precursors of RA. We mapped this RA requirement to early gastrula stages during the induction of neural plate precursors. This reduced RA signaling results in abnormal expression of neural network genes, including the neural plate stem cell maintenance genes, geminin, and foxd4l1.1. This abnormal expression of neural network genes results in increased proliferation of neural precursors giving rise to an expanded neural plate. Conclusion: We show that RA signaling is required for neural tube closure during embryogenesis. RA signaling plays a very early role in the regulation of proliferation and differentiation of the neural plate soon after the induction of neural progenitors during gastrulation. RA signaling disruption leads to the induction of NTDs through the mis regulation of the early neuroectodermal network, leading to increased proliferation resulting in the expansion of the neural plate. Ethanol exposure induces NTDs through this mechanism involving reduced RA levels.
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Affiliation(s)
| | | | | | - Abraham Fainsod
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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2
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Thawani A, Maunsell HR, Zhang H, Ankamreddy H, Groves AK. The Foxi3 transcription factor is necessary for the fate restriction of placodal lineages at the neural plate border. Development 2023; 150:dev202047. [PMID: 37756587 PMCID: PMC10617604 DOI: 10.1242/dev.202047] [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: 05/30/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023]
Abstract
The Foxi3 transcription factor, expressed in the neural plate border at the end of gastrulation, is necessary for the formation of posterior placodes and is thus important for ectodermal patterning. We have created two knock-in mouse lines expressing GFP or a tamoxifen-inducible Cre recombinase to show that Foxi3 is one of the earliest genes to label the border between the neural tube and epidermis, and that Foxi3-expressing neural plate border progenitors contribute primarily to cranial placodes and epidermis from the onset of expression, but not to the neural crest or neural tube lineages. By simultaneously knocking out Foxi3 in neural plate border cells and following their fates, we show that neural plate border cells lacking Foxi3 contribute to all four lineages of the ectoderm - placodes, epidermis, crest and neural tube. We contrast Foxi3 with another neural plate border transcription factor, Zic5, the progenitors of which initially contribute broadly to all germ layers until gastrulation and gradually become restricted to the neural crest lineage and dorsal neural tube cells. Our study demonstrates that Foxi3 uniquely acts early at the neural plate border to restrict progenitors to a placodal and epidermal fate.
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Affiliation(s)
- Ankita Thawani
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Helen R. Maunsell
- Program in Development, Disease Models and Therapeutics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hongyuan Zhang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Andrew K. Groves
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
- Program in Development, Disease Models and Therapeutics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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3
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Collins C, Ventrella R, Mitchell BJ. Building a ciliated epithelium: Transcriptional regulation and radial intercalation of multiciliated cells. Curr Top Dev Biol 2020; 145:3-39. [PMID: 34074533 DOI: 10.1016/bs.ctdb.2020.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The epidermis of the Xenopus embryo has emerged as a powerful tool for studying the development of a ciliated epithelium. Interspersed throughout the epithelium are multiciliated cells (MCCs) with 100+ motile cilia that beat in a coordinated manner to generate fluid flow over the surface of the cell. MCCs are essential for various developmental processes and, furthermore, ciliary dysfunction is associated with numerous pathologies. Therefore, understanding the cellular mechanisms involved in establishing a ciliated epithelium are of particular interest. MCCs originate in the inner epithelial layer of Xenopus skin, where Notch signaling plays a critical role in determining which progenitors will adopt a ciliated cell fate. Then, activation of various transcriptional regulators, such as GemC1 and MCIDAS, initiate the MCC transcriptional program, resulting in centriole amplification and the formation of motile cilia. Following specification and differentiation, MCCs undergo the process of radial intercalation, where cells apically migrate from the inner layer to the outer epithelial layer. This process involves the cooperation of various cytoskeletal networks, activation of various signaling molecules, and changes in cell-ECM and cell-cell adhesion. Coordination of these cellular processes is required for complete incorporation into the outer epithelial layer and generation of a functional ciliated epithelium. Here, we highlight recent advances made in understanding the transcriptional cascades required for MCC specification and differentiation and the coordination of cellular processes that facilitate radial intercalation. Proper regulation of these signaling pathways and processes are the foundation for developing a ciliated epithelium.
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Affiliation(s)
- Caitlin Collins
- Department of Cell and Developmental Biology, Lurie Comprehensive Cancer Center, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Rosa Ventrella
- Department of Cell and Developmental Biology, Lurie Comprehensive Cancer Center, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States
| | - Brian J Mitchell
- Department of Cell and Developmental Biology, Lurie Comprehensive Cancer Center, Northwestern University, Feinberg School of Medicine, Chicago, IL, United States.
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4
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Zhou XL, Wei Y, Chen XY, Chen P, Tang XF, Zhang Q, Dong ZQ, Pan MH, Lu C. BmGeminin2 interacts with BmRRS1 and regulates Bombyx mori cell proliferation. Cell Cycle 2019; 18:1498-1512. [PMID: 31145019 DOI: 10.1080/15384101.2019.1624109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Geminin is a master regulator of cell-cycle progression that ensures the timely onset of DNA replication and prevents re-replication in vertebrates and invertebrates. Previously, we identified two Geminin genes, BmGeminin1 and BmGeminn2, in the silkworm Bombyx mori, and we found that RNA interference of BmGeminin1 led to re-replication. However, the function of BmGeminin2 remains poorly understood. In this study, we found that knockdown of BmGeminin2 can improve cell proliferation, and upregulated G2/M-associated gene-cyclinB/CDK1 expression. Then, we performed yeast two-hybrid screening to identify interacting proteins. Our results yielded 23 interacting proteins, which are involved in DNA replication, chromosome stabilization, embryonic development, energy, defense, protein processing, or structural protein. Here, we focused on BmRRS1, a chromosome congression-related protein that is closely related to cell cycle G2/M progression. The interaction between BmGeminin2 and BmRRS1 was confirmed by immunofluorescence and immunoprecipitation. Analysis of its expression profile showed that BmRRS1 was related to BmGeminin2. In addition, BmGeminin2 overexpression downregulated the BmRRS1 transcript. Knockdown of BmGeminin2 led to upregulation of the BmRRS1 transcript. Furthermore, overexpression of BmRRS1 can upregulate G2/M-associated gene-cyclinB/CDK1 expression, and improved cell proliferation, consistent with the effects of BmGeminin2 knockout. In addition, BmRRS1 RNA interference can eliminate the impact of BmGem2 knockout on cell proliferation, the ratio of cell cycle stage and the expression of cyclinB/CDK1. These data suggested that the cell proliferation advantage of BmGeminin2 knockout was closely related to BmRRS1. Our findings provide insight into the functions of Geminin and the mechanisms underlying the regulation of the cell cycle in the silkworm.
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Affiliation(s)
- Xiao-Lin Zhou
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - Yi Wei
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - Xiang-Yun Chen
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - Peng Chen
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,b Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry , Southwest University , Chongqing , China
| | - Xiao-Fang Tang
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - Qian Zhang
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - Zhan-Qi Dong
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,b Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry , Southwest University , Chongqing , China
| | - Min-Hui Pan
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,b Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry , Southwest University , Chongqing , China
| | - Cheng Lu
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,b Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry , Southwest University , Chongqing , China
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5
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Liang SY, Zhou YL, Shu MQ, Lin S. Regulation of geminin by neuropeptide Y in vascular smooth muscle cell proliferation : A current review. Herz 2018; 44:712-716. [PMID: 30151710 DOI: 10.1007/s00059-018-4721-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/25/2018] [Accepted: 06/01/2018] [Indexed: 11/30/2022]
Abstract
Geminin, a key regulator of DNA replication licensing in the cell cycle, plays an essential role in determining the fate of cells via suppression of cell proliferation and cellular differentiation. Neuropeptide Y (NPY) intensifies the proliferation of vascular smooth muscle cells (VSMCs) directly by binding with Y1 receptors. In vitro experiments have shown that stimulation of NPY on VSMCs via regulation of geminin is a double-edged sword. Given that the proliferation and the phenotypic transformation of VSMCs increase the risk for progression of atherosclerosis, we focus on the role of geminin interference in determining the fate of VSMCs. Furthermore, we discuss the therapeutic potential of peripheral neurotransmitter interference, thus pointing toward future research directions in the treatment of atherosclerosis.
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Affiliation(s)
- S-Y Liang
- Department of Cardiology, Southwest Hospital, Third Military Medical University, No. 30 Gaotanyan, Shapingba, 400038, Chongqing, China
| | - Y-L Zhou
- Department of Cardiology, Southwest Hospital, Third Military Medical University, No. 30 Gaotanyan, Shapingba, 400038, Chongqing, China
| | - M-Q Shu
- Department of Cardiology, Southwest Hospital, Third Military Medical University, No. 30 Gaotanyan, Shapingba, 400038, Chongqing, China.
| | - S Lin
- Department of Cardiology, Southwest Hospital, Third Military Medical University, No. 30 Gaotanyan, Shapingba, 400038, Chongqing, China.
- School of Health Science, IIIawarra Health and Medical Research Institute, University of Wollongong, NSW 2522, Wollongong City, Australia.
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6
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Geminin Orchestrates Somite Formation by Regulating Fgf8 and Notch Signaling. BIOMED RESEARCH INTERNATIONAL 2018; 2018:6543196. [PMID: 29984243 PMCID: PMC6011172 DOI: 10.1155/2018/6543196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/24/2018] [Accepted: 05/08/2018] [Indexed: 11/20/2022]
Abstract
During somitogenesis, Fgf8 maintains the predifferentiation stage of presomitic mesoderm (PSM) cells and its retraction gives a cue for somite formation. Delta/Notch initiates the expression of oscillation genes in the tail bud and subsequently contributes to somite formation in a periodic way. Whether there exists a critical factor coordinating Fgf8 and Notch signaling pathways is largely unknown. Here, we demonstrate that the loss of function of geminin gave rise to narrower somites as a result of derepressed Fgf8 gradient in the PSM and tail bud. Furthermore, in geminin morphants, the somite boundary could not form properly but the oscillation of cyclic genes was normal, displaying the blurry somitic boundary and disturbed somite polarity along the AP axis. In mechanism, these manifestations were mediated by the disrupted association of the geminin/Brg1 complex with intron 3 of mib1. The latter interaction was found to positively regulate mib1 transcription, Notch activity, and sequential somite segmentation during somitogenesis. In addition, geminin was also shown to regulate the expression of deltaD in mib1-independent way. Collectively, our data for the first time demonstrate that geminin regulates Fgf8 and Notch signaling to regulate somite segmentation during somitogenesis.
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7
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Sankar S, Patterson E, Lewis EM, Waller LE, Tong C, Dearborn J, Wozniak D, Rubin JB, Kroll KL. Geminin deficiency enhances survival in a murine medulloblastoma model by inducing apoptosis of preneoplastic granule neuron precursors. Genes Cancer 2017; 8:725-744. [PMID: 29234490 PMCID: PMC5724806 DOI: 10.18632/genesandcancer.157] [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] [Indexed: 01/08/2023] Open
Abstract
Medulloblastoma is the most common malignant brain cancer of childhood. Further understanding of tumorigenic mechanisms may define new therapeutic targets. Geminin maintains genome fidelity by controlling re-initiation of DNA replication within a cell cycle. In some contexts, Geminin inhibition induces cancer-selective cell cycle arrest and apoptosis and/or sensitizes cancer cells to Topoisomerase IIα inhibitors such as etoposide, which is used in combination chemotherapies for medulloblastoma. However, Geminin's potential role in medulloblastoma tumorigenesis remained undefined. Here, we found that Geminin is highly expressed in human and mouse medulloblastomas and in murine granule neuron precursor (GNP) cells during cerebellar development. Conditional Geminin loss significantly enhanced survival in the SmoA1 mouse medulloblastoma model. Geminin loss in this model also reduced numbers of preneoplastic GNPs persisting at one postnatal month, while at two postnatal weeks these cells exhibited an elevated DNA damage response and apoptosis. Geminin knockdown likewise impaired human medulloblastoma cell growth, activating G2 checkpoint and DNA damage response pathways, triggering spontaneous apoptosis, and enhancing G2 accumulation of cells in response to etoposide treatment. Together, these data suggest preneoplastic and cancer cell-selective roles for Geminin in medulloblastoma, and suggest that targeting Geminin may impair tumor growth and enhance responsiveness to Topoisomerase IIα-directed chemotherapies.
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Affiliation(s)
- Savita Sankar
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Ethan Patterson
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Emily M Lewis
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Laura E Waller
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Caili Tong
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO, USA
| | - Joshua Dearborn
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, USA
| | - David Wozniak
- Department of Psychiatry, Washington University School of Medicine, Saint Louis, MO, USA
| | - Joshua B Rubin
- Department of Pediatrics, Washington University School of Medicine, Saint Louis, MO, USA
| | - Kristen L Kroll
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO, USA
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Arbi M, Pefani DE, Taraviras S, Lygerou Z. Controlling centriole numbers: Geminin family members as master regulators of centriole amplification and multiciliogenesis. Chromosoma 2017; 127:151-174. [PMID: 29243212 DOI: 10.1007/s00412-017-0652-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 11/06/2017] [Accepted: 11/07/2017] [Indexed: 01/18/2023]
Abstract
To ensure that the genetic material is accurately passed down to daughter cells during mitosis, dividing cells must duplicate their chromosomes and centrosomes once and only once per cell cycle. The same key steps-licensing, duplication, and segregation-control both the chromosome and the centrosome cycle, which must occur in concert to safeguard genome integrity. Aberrations in genome content or centrosome numbers lead to genomic instability and are linked to tumorigenesis. Such aberrations, however, can also be part of the normal life cycle of specific cell types. Multiciliated cells best exemplify the deviation from a normal centrosome cycle. They are post-mitotic cells which massively amplify their centrioles, bypassing the rule for once-per-cell-cycle centriole duplication. Hundreds of centrioles dock to the apical cell surface and generate motile cilia, whose concerted movement ensures fluid flow across epithelia. The early steps that control the generation of multiciliated cells have lately started to be elucidated. Geminin and the vertebrate-specific GemC1 and McIdas are distantly related coiled-coil proteins, initially identified as cell cycle regulators associated with the chromosome cycle. Geminin is required to ensure once-per-cell-cycle genome replication, while McIdas and GemC1 bind to Geminin and are implicated in DNA replication control. Recent findings highlight Geminin family members as early regulators of multiciliogenesis. GemC1 and McIdas specify the multiciliate cell fate by forming complexes with the E2F4/5 transcription factors to switch on a gene expression program leading to centriole amplification and cilia formation. Positive and negative interactions among Geminin family members may link cell cycle control to centriole amplification and multiciliogenesis, acting close to the point of transition from proliferation to differentiation. We review key steps of centrosome duplication and amplification, present the role of Geminin family members in the centrosome and chromosome cycle, and discuss links with disease.
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Affiliation(s)
- Marina Arbi
- Laboratory of Biology, School of Medicine, University of Patras, 26504 Rio, Patras, Greece
| | - Dafni-Eleftheria Pefani
- Laboratory of Biology, School of Medicine, University of Patras, 26504 Rio, Patras, Greece.,CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Stavros Taraviras
- Laboratory of Physiology, School of Medicine, University of Patras, 26504 Rio, Patras, Greece
| | - Zoi Lygerou
- Laboratory of Biology, School of Medicine, University of Patras, 26504 Rio, Patras, Greece.
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9
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Yuan Y, Ma XS, Liang QX, Xu ZY, Huang L, Meng TG, Lin F, Schatten H, Wang ZB, Sun QY. Geminin deletion in pre-meiotic DNA replication stage causes spermatogenesis defect and infertility. J Reprod Dev 2017; 63:481-488. [PMID: 28690291 PMCID: PMC5649097 DOI: 10.1262/jrd.2017-036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Geminin plays a critical role in cell cycle regulation by regulating DNA replication and serves as a transcriptional molecular switch that directs cell fate decisions. Spermatogonia lacking Geminin disappear
during the initial wave of mitotic proliferation, while geminin is not required for meiotic progression of spermatocytes. It is unclear whether geminin plays a role in pre-meiotic DNA replication in later-stage spermatogonia and
their subsequent differentiation. Here, we selectively disrupted Geminin in the male germline using the Stra8-Cre/loxP conditional knockout system.
Geminin-deficient mice showed atrophic testes and infertility, concomitant with impaired spermatogenesis and reduced sperm motility. The number of undifferentiated spermatogonia and spermatocytes was significantly
reduced; the pachytene stage was impaired most severely. Expression of cell proliferation-associated genes was reduced in Gmnnfl/Δ; Stra8-Cre testes compared to in controls. Increased
DNA damage, decreased Cdt1, and increased phosphorylation of Chk1/Chk2 were observed in Geminin-deficient germ cells. These results suggest that geminin plays important roles in pre-meiotic DNA replication and
subsequent spermatogenesis.
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Affiliation(s)
- Yue Yuan
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Xue-Shan Ma
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,The Reproductive Medical Center, the First Affiliated Hospital, Zhengzhou University, Zhengzhou 450052, China
| | - Qiu-Xia Liang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhao-Yang Xu
- The Reproductive Medical Center, the First Affiliated Hospital, Zhengzhou University, Zhengzhou 450052, China
| | - Lin Huang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tie-Gang Meng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Fei Lin
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Zhen-Bo Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
| | - Qing-Yuan Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100101, China
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Zhang L, Cai M, Gong Z, Zhang B, Li Y, Guan L, Hou X, Li Q, Liu G, Xue Z, Yang MH, Ye J, Chin YE, You H. Geminin facilitates FoxO3 deacetylation to promote breast cancer cell metastasis. J Clin Invest 2017; 127:2159-2175. [PMID: 28436938 DOI: 10.1172/jci90077] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 02/21/2017] [Indexed: 01/29/2023] Open
Abstract
Geminin expression is essential for embryonic development and the maintenance of chromosomal integrity. In spite of this protective role, geminin is also frequently overexpressed in human cancers and the molecular mechanisms underlying its role in tumor progression remain unclear. The histone deacetylase HDAC3 modulates transcription factors to activate or suppress transcription. Little is known about how HDAC3 specifies substrates for modulation among highly homologous transcription factor family members. Here, we have demonstrated that geminin selectively couples the transcription factor forkhead box O3 (FoxO3) to HDAC3, thereby specifically facilitating FoxO3 deacetylation. We determined that geminin-associated HDAC3 deacetylates FoxO3 to block its transcriptional activity, leading to downregulation of the downstream FoxO3 target Dicer, an RNase that suppresses metastasis. Breast cancer cells depleted of geminin or HDAC3 exhibited poor metastatic potential that was attributed to reduced suppression of the FoxO3-Dicer axis. Moreover, elevated levels of geminin, HDAC3, or both together with decreased FoxO3 acetylation and reduced Dicer expression were detected in aggressive human breast cancer specimens. These results underscore a prominent role for geminin in promoting breast cancer metastasis via the enzyme-substrate-coupling mechanism in HDAC3-FoxO3 complex formation.
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Affiliation(s)
- Lei Zhang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, and
| | - Meizhen Cai
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, and
| | - Zhicheng Gong
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, and
| | - Bingchang Zhang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, and
| | - Yuanpei Li
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, and
| | - Li Guan
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, and
| | - Xiaonan Hou
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, and
| | - Qing Li
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, and
| | - Gang Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics Center for Molecular Imaging and Translational Medicine School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Zengfu Xue
- Xiamen Cancer Center, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China
| | - Muh-Hua Yang
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Jing Ye
- Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shanxi, China
| | - Y Eugene Chin
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences-Jiaotong University School of Medicine, Shanghai, China
| | - Han You
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, and
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11
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Tang XF, Chen XY, Zhang CD, Li YF, Liu TH, Zhou XL, Wang L, Zhang Q, Chen P, Lu C, Pan MH. Two Geminin homologs regulate DNA replication in silkworm, Bombyx mori. Cell Cycle 2017; 16:830-840. [PMID: 28379781 DOI: 10.1080/15384101.2017.1282582] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
DNA replication is rigorously controlled in cells to ensure that the genome duplicates exactly once per cell cycle. Geminin is a small nucleoprotein, which prevents DNA rereplication by directly binding to and inhibiting the DNA replication licensing factor, Cdt1. In this study, we have identified 2 Geminin genes, BmGeminin1 and BmGeminn2, in silkworm, Bombyx mori. These genes contain the Geminin conserved coiled-coil domain and are periodically localized in the nucleus during the S-G2 phase but are degraded at anaphase in mitosis. Both BmGeminin1 and BmGeminin2 are able to homodimerize and interact with BmCdt1 in cells. In addition, BmGeminin1 and BmGeminin2 can interact with each other. Overexpression of BmGeminin1 affects cell cycle progression: cell cycle is arrested in S phase, and RNA interference of BmGeminin1 leads to rereplication. In contrast, overexpression or knockdown of BmGeminin2 with RNAi did not significantly affect cell cycle, while more rereplication occurred when BmGeminin1 and BmGeminin2 together were knocked down in cells than when only BmGeminin1 was knocked down. These data suggest that both BmGeminin1 and BmGeminin2 are involved in the regulation of DNA replication. These findings provide insight into the function of Geminin and contribute to our understanding of the regulation mechanism of cell cycle in silkworm.
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Affiliation(s)
- Xiao-Fang Tang
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - Xiang-Yun Chen
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,b Basic Medical School , Guiyang College of Traditional Chinese Medicine , Guiyang , China
| | - Chun-Dong Zhang
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,c Department of Biochemistry and Molecular Biology , Chongqing Medical University , Chongqing , China
| | - Yao-Feng Li
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,b Basic Medical School , Guiyang College of Traditional Chinese Medicine , Guiyang , China
| | - Tai-Hang Liu
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - Xiao-Lin Zhou
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - La Wang
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - Qian Zhang
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China
| | - Peng Chen
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,d Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry , Southwest University , Chongqing , China
| | - Cheng Lu
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,d Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry , Southwest University , Chongqing , China
| | - Min-Hui Pan
- a State Key Laboratory of Silkworm Genome Biology , Southwest University , Chongqing , China.,d Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry , Southwest University , Chongqing , China
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12
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Sherman JH, Karpinski BA, Fralish MS, Cappuzzo JM, Dhindsa DS, Thal AG, Moody SA, LaMantia AS, Maynard TM. Foxd4 is essential for establishing neural cell fate and for neuronal differentiation. Genesis 2017; 55. [PMID: 28316121 DOI: 10.1002/dvg.23031] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 03/10/2017] [Accepted: 03/13/2017] [Indexed: 01/21/2023]
Abstract
Many molecular factors required for later stages of neuronal differentiation have been identified; however, much less is known about the early events that regulate the initial establishment of the neuroectoderm. We have used an in vitro embryonic stem cell (ESC) differentiation model to investigate early events of neuronal differentiation and to define the role of mouse Foxd4, an ortholog of a forkhead-family transcription factor central to Xenopus neural plate/neuroectodermal precursor development. We found that Foxd4 is a necessary regulator of the transition from pluripotent ESC to neuroectodermal stem cell, and its expression is necessary for neuronal differentiation. Mouse Foxd4 expression is not only limited to the neural plate but it is also expressed and apparently functions to regulate neurogenesis in the olfactory placode. These in vitro results suggest that mouse Foxd4 has a similar function to its Xenopus ortholog; this was confirmed by successfully substituting murine Foxd4 for its amphibian counterpart in overexpression experiments. Thus, Foxd4 appears to regulate the initial steps in establishing neuroectodermal precursors during initial development of the nervous system.
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Affiliation(s)
- Jonathan H Sherman
- Department of Neurological Surgery, George Washington University Hospital, Washington, District of Columbia.,Institute for Neuroscience, George Washington University, Washington, District of Columbia
| | - Beverly A Karpinski
- Institute for Neuroscience, George Washington University, Washington, District of Columbia.,Department of Pharmacology and Physiology, George Washington University SMHS, Washington, District of Columbia
| | - Matthew S Fralish
- Institute for Neuroscience, George Washington University, Washington, District of Columbia.,Department of Pharmacology and Physiology, George Washington University SMHS, Washington, District of Columbia
| | | | | | - Arielle G Thal
- George Washington University SMHS, Washington, District of Columbia
| | - Sally A Moody
- Institute for Neuroscience, George Washington University, Washington, District of Columbia.,Department of Anatomy and Regenerative Biology, George Washington University SMHS, Washington, District of Columbia
| | - Anthony S LaMantia
- Institute for Neuroscience, George Washington University, Washington, District of Columbia.,Department of Pharmacology and Physiology, George Washington University SMHS, Washington, District of Columbia
| | - Thomas M Maynard
- Institute for Neuroscience, George Washington University, Washington, District of Columbia.,Department of Pharmacology and Physiology, George Washington University SMHS, Washington, District of Columbia
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13
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Hosogane M, Bosu L, Fukumoto E, Yamada H, Sato S, Nakayama K. Geminin is an indispensable inhibitor of Cdt1 in mouse embryonic stem cells. Genes Cells 2017; 22:360-375. [DOI: 10.1111/gtc.12482] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/26/2017] [Indexed: 11/26/2022]
Affiliation(s)
- Masaki Hosogane
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Lena Bosu
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Emiko Fukumoto
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Hidetoshi Yamada
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Soichiro Sato
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
| | - Keiko Nakayama
- Department of Cell Proliferation, United Center for Advanced Research and Translational Medicine, Graduate School of Medicine; Tohoku University; 2-1 Seiryo-machi, Aoba-ku Sendai Miyagi 980-8575 Japan
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14
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Liu X, Xia Y, Tang J, Ma L, Li C, Ma P, Mao B. Dual roles of Akirin2 protein during Xenopus neural development. J Biol Chem 2017; 292:5676-5684. [PMID: 28193841 DOI: 10.1074/jbc.m117.777110] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/10/2017] [Indexed: 11/06/2022] Open
Abstract
To ensure correct spatial and temporal patterning, embryos must maintain pluripotent cell populations and control when cells undergo commitment. The newly identified nucleoprotein Akirin has been shown to modulate the innate immune response through epigenetic regulation and to play important roles in other physiological processes, but its role in neural development remains unknown. Here we show that Akirin2 is required for neural development in Xenopus and that knockdown of Akirin2 expands the expression of the neural progenitor marker Sox2 and inhibits expression of the differentiated neuronal marker N-tubulin. Akirin2 acts antagonistically to Geminin, thus regulating Sox2 expression, and maintains the neural precursor state by participating in the Brg1/Brm-associated factor (BAF) complex mediated by BAF53a. Additionally, Akirin2 also modulates N-tubulin expression by acting upstream of neuronal differentiation 1 (NeuroD) and in parallel with neurogenin-related 1 (Ngnr1) during terminal neuronal differentiation. Thus, our results reveal a novel model in which Akirin2 precisely coordinates and temporally controls Xenopus neural development.
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Affiliation(s)
- Xiaoliang Liu
- From the State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China and.,the Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650203, China
| | - Yingjie Xia
- From the State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China and
| | - Jixin Tang
- From the State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China and
| | - Li Ma
- From the State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China and
| | - Chaocui Li
- From the State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China and
| | - Pengcheng Ma
- From the State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China and
| | - Bingyu Mao
- From the State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China and
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15
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Sankar S, Yellajoshyula D, Zhang B, Teets B, Rockweiler N, Kroll KL. Gene regulatory networks in neural cell fate acquisition from genome-wide chromatin association of Geminin and Zic1. Sci Rep 2016; 6:37412. [PMID: 27881878 PMCID: PMC5121602 DOI: 10.1038/srep37412] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 10/28/2016] [Indexed: 12/30/2022] Open
Abstract
Neural cell fate acquisition is mediated by transcription factors expressed in nascent neuroectoderm, including Geminin and members of the Zic transcription factor family. However, regulatory networks through which this occurs are not well defined. Here, we identified Geminin-associated chromatin locations in embryonic stem cells and Geminin- and Zic1-associated locations during neural fate acquisition at a genome-wide level. We determined how Geminin deficiency affected histone acetylation at gene promoters during this process. We integrated these data to demonstrate that Geminin associates with and promotes histone acetylation at neurodevelopmental genes, while Geminin and Zic1 bind a shared gene subset. Geminin- and Zic1-associated genes exhibit embryonic nervous system-enriched expression and encode other regulators of neural development. Both Geminin and Zic1-associated peaks are enriched for Zic1 consensus binding motifs, while Zic1-bound peaks are also enriched for Sox3 motifs, suggesting co-regulatory potential. Accordingly, we found that Geminin and Zic1 could cooperatively activate the expression of several shared targets encoding transcription factors that control neurogenesis, neural plate patterning, and neuronal differentiation. We used these data to construct gene regulatory networks underlying neural fate acquisition. Establishment of this molecular program in nascent neuroectoderm directly links early neural cell fate acquisition with regulatory control of later neurodevelopment.
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Affiliation(s)
- Savita Sankar
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Avenue, Saint Louis, MO 63110, USA
| | - Dhananjay Yellajoshyula
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Avenue, Saint Louis, MO 63110, USA
| | - Bo Zhang
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Avenue, Saint Louis, MO 63110, USA
| | - Bryan Teets
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Avenue, Saint Louis, MO 63110, USA
| | - Nicole Rockweiler
- Department of Genetics, Washington University School of Medicine, 660 S. Euclid Avenue, Saint Louis, MO 63110, USA
| | - Kristen L Kroll
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Avenue, Saint Louis, MO 63110, USA
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16
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Patmanidi AL, Champeris Tsaniras S, Karamitros D, Kyrousi C, Lygerou Z, Taraviras S. Concise Review: Geminin-A Tale of Two Tails: DNA Replication and Transcriptional/Epigenetic Regulation in Stem Cells. Stem Cells 2016; 35:299-310. [DOI: 10.1002/stem.2529] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 09/18/2016] [Accepted: 10/01/2016] [Indexed: 12/14/2022]
Affiliation(s)
| | | | - Dimitris Karamitros
- Department of Physiology; Medical School, University of Patras; Rio Patras Greece
| | - Christina Kyrousi
- Department of Physiology; Medical School, University of Patras; Rio Patras Greece
| | - Zoi Lygerou
- Department of Biology; Medical School, University of Patras; Rio Patras Greece
| | - Stavros Taraviras
- Department of Physiology; Medical School, University of Patras; Rio Patras Greece
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17
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Lu F, Wu X, Yin F, Chia-Fang Lee C, Yu M, Mihaylov IS, Yu J, Sun H, Zhang H. Regulation of DNA replication and chromosomal polyploidy by the MLL-WDR5-RBBP5 methyltransferases. Biol Open 2016; 5:1449-1460. [PMID: 27744293 PMCID: PMC5087680 DOI: 10.1242/bio.019729] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
DNA replication licensing occurs on chromatin, but how the chromatin template is regulated for replication remains mostly unclear. Here, we have analyzed the requirement of histone methyltransferases for a specific type of replication: the DNA re-replication induced by the downregulation of either Geminin, an inhibitor of replication licensing protein CDT1, or the CRL4CDT2 ubiquitin E3 ligase. We found that siRNA-mediated reduction of essential components of the MLL-WDR5-RBBP5 methyltransferase complexes including WDR5 or RBBP5, which transfer methyl groups to histone H3 at K4 (H3K4), suppressed DNA re-replication and chromosomal polyploidy. Reduction of WDR5/RBBP5 also prevented the activation of H2AX checkpoint caused by re-replication, but not by ultraviolet or X-ray irradiation; and the components of MLL complexes co-localized with the origin recognition complex (ORC) and MCM2-7 replicative helicase complexes at replication origins to control the levels of methylated H3K4. Downregulation of WDR5 or RBBP5 reduced the methylated H3K4 and suppressed the recruitment of MCM2-7 complexes onto replication origins. Our studies indicate that the MLL complexes and H3K4 methylation are required for DNA replication but not for DNA damage repair. Summary: DNA replication or re-replication of DNA induced after loss of Geminin or CLR4CDT2 is regulated by the methylation activities of the MLL-WDR5-RBBP5 methyltransferases on histone H3 at lysine 4 (H3K4).
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Affiliation(s)
- Fei Lu
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, China Basic Science Division, Nevada Cancer Institute, Las Vegas, NV 89135, USA
| | - Xiaojun Wu
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, China
| | - Feng Yin
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, China
| | | | - Min Yu
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, Guangdong 518055, China
| | - Ivailo S Mihaylov
- Basic Science Division, Nevada Cancer Institute, Las Vegas, NV 89135, USA
| | - Jiekai Yu
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154, USA
| | - Hong Sun
- Basic Science Division, Nevada Cancer Institute, Las Vegas, NV 89135, USA Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154, USA
| | - Hui Zhang
- Basic Science Division, Nevada Cancer Institute, Las Vegas, NV 89135, USA Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV 89154, USA
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18
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Kushwaha PP, Rapalli KC, Kumar S. Geminin a multi task protein involved in cancer pathophysiology and developmental process: A review. Biochimie 2016; 131:115-127. [PMID: 27702582 DOI: 10.1016/j.biochi.2016.09.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 09/29/2016] [Indexed: 02/05/2023]
Abstract
DNA replicates in a timely manner with each cell division. Multiple proteins and factors are involved in the initiation of DNA replication including a dynamic interaction between Cdc10-dependent transcript (Cdt1) and Geminin (GMNN). A conformational change between GMNN-Cdt1 heterotrimer and heterohexamer complex is responsible for licensing or inhibition of the DNA replication. This molecular switch ensures a faithful DNA replication during each S phase of cell cycle. GMNN inhibits Cdt1-mediated minichromosome maintenance helicases (MCM) loading onto the chromatin-bound origin recognition complex (ORC) which results in the inhibition of pre-replication complex assembly. GMNN modulates DNA replication by direct binding to Cdt1, and thereby alters its stability and activity. GMNN is involved in various stages of development such as pre-implantation, germ layer formation, cell commitment and specification, maintenance of genome integrity at mid blastula transition, epithelial to mesenchymal transition during gastrulation, neural development, organogenesis and axis patterning. GMNN interacts with different proteins resulting in enhanced hematopoietic stem cell activity thereby activating the development-associated genes' transcription. GMNN expression is also associated with cancer pathophysiology and development. In this review we discussed the structure and function of GMNN in detail. Inhibitors of GMNN and their role in DNA replication, repair, cell cycle and apoptosis are reviewed. Further, we also discussed the role of GMNN in virus infected host cells.
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Affiliation(s)
- Prem Prakash Kushwaha
- School of Basic and Applied Sciences, Centre for Biochemistry and Microbial Sciences, Central University of Punjab, Bathinda, 151001, India
| | - Krishna Chaitanya Rapalli
- School of Basic and Applied Sciences, Centre for Animal Sciences, Central University of Punjab, Bathinda, 151001, India
| | - Shashank Kumar
- School of Basic and Applied Sciences, Centre for Biochemistry and Microbial Sciences, Central University of Punjab, Bathinda, 151001, India.
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19
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Role of Geminin in cell fate determination of hematopoietic stem cells (HSCs). Int J Hematol 2016; 104:324-9. [PMID: 27422432 DOI: 10.1007/s12185-016-2060-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 07/10/2016] [Accepted: 07/11/2016] [Indexed: 01/05/2023]
Abstract
Geminin exerts two distinct molecular roles. Geminin negatively regulates DNA replication licensing through the direct interaction with Cdt1 to prevent re-replication in proliferating cells. Geminin also regulates chromatin remodeling through the direct interaction with Brahma/Brg1 to maintain undifferentiated states of stem cells. We previously uncovered that Polycomb-group complex 1 and Hoxb4/Hoxa9, well-known intrinsic factors that are essential for maintaining the hematopoietic stem cell (HSC) activity, alternatively act as ubiquitin-proteasome systems for Geminin protein to reduce the protein expression level, and sustain the HSC activity. Thus, Geminin is presumed to play an important role in determining cell fate, i.e., turning on and off cellular quiescence and proliferation/differentiation, in HSCs. We recently generated recombinant cell-penetrating Geminin (CP-Geminin), enabling rapid incorporation and withdraw of Geminin protein in cells. CP-Geminin may be useful in regulating the cell cycle and chromatin configuration. In this article, we summarize current information on the molecular functions of Geminin and the regulatory system for Geminin protein expression, and argue for the molecular role of Geminin in cell fate determination of HSCs, and future perspective of a new technology for manipulating the activities of HSCs and cancer stem cells (CSCs).
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20
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Gaur S, Mandelbaum M, Herold M, Majumdar HD, Neilson KM, Maynard TM, Mood K, Daar IO, Moody SA. Neural transcription factors bias cleavage stage blastomeres to give rise to neural ectoderm. Genesis 2016; 54:334-49. [PMID: 27092474 PMCID: PMC4912902 DOI: 10.1002/dvg.22943] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/13/2016] [Accepted: 04/15/2016] [Indexed: 01/23/2023]
Abstract
The decision by embryonic ectoderm to give rise to epidermal versus neural derivatives is the result of signaling events during blastula and gastrula stages. However, there also is evidence in Xenopus that cleavage stage blastomeres contain maternally derived molecules that bias them toward a neural fate. We used a blastomere explant culture assay to test whether maternally deposited transcription factors bias 16-cell blastomere precursors of epidermal or neural ectoderm to express early zygotic neural genes in the absence of gastrulation interactions or exogenously supplied signaling factors. We found that Foxd4l1, Zic2, Gmnn, and Sox11 each induced explants made from ventral, epidermis-producing blastomeres to express early neural genes, and that at least some of the Foxd4l1 and Zic2 activities are required at cleavage stages. Similarly, providing extra Foxd4l1 or Zic2 to explants made from dorsal, neural plate-producing blastomeres significantly increased the expression of early neural genes, whereas knocking down either significantly reduced them. These results show that maternally delivered transcription factors bias cleavage stage blastomeres to a neural fate. We demonstrate that mouse and human homologs of Foxd4l1 have similar functional domains compared to the frog protein, as well as conserved transcriptional activities when expressed in Xenopus embryos and blastomere explants. genesis 54:334-349, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Shailly Gaur
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | - Max Mandelbaum
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | - Mona Herold
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | - Himani Datta Majumdar
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | - Karen M. Neilson
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
| | | | - Kathy Mood
- Laboratory of Cell and Developmental Signaling, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Ira O. Daar
- Laboratory of Cell and Developmental Signaling, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Sally A. Moody
- Department of Anatomy and Regenerative Biology, George Washington University, School of Medicine and Health Sciences, 2300 I Street, NW, Washington DC, USA
- George Washington University Institute for Neuroscience
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21
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Arbi M, Pefani DE, Kyrousi C, Lalioti ME, Kalogeropoulou A, Papanastasiou AD, Taraviras S, Lygerou Z. GemC1 controls multiciliogenesis in the airway epithelium. EMBO Rep 2016; 17:400-13. [PMID: 26882546 DOI: 10.15252/embr.201540882] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 01/04/2016] [Indexed: 12/20/2022] Open
Abstract
Multiciliated cells are terminally differentiated, post-mitotic cells that form hundreds of motile cilia on their apical surface. Defects in multiciliated cells lead to disease, including mucociliary clearance disorders that result from ciliated cell disfunction in airways. The pathway controlling multiciliogenesis, however, remains poorly characterized. We showed that GemC1, previously implicated in cell cycle control, is a central regulator of ciliogenesis. GemC1 is specifically expressed in ciliated epithelia. Ectopic expression of GemC1 is sufficient to induce early steps of multiciliogenesis in airway epithelial cells ex vivo, upregulating McIdas and FoxJ1, key transcriptional regulators of multiciliogenesis. GemC1 directly transactivates the McIdas and FoxJ1 upstream regulatory sequences, and its activity is enhanced by E2F5 and inhibited by Geminin. GemC1-knockout mice are born with airway epithelia devoid of multiciliated cells. Our results identify GemC1 as an essential regulator of ciliogenesis in the airway epithelium and a candidate gene for mucociliary disorders.
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Affiliation(s)
- Marina Arbi
- Laboratory of Biology, School of Medicine, University of Patras, Patras, Greece
| | | | - Christina Kyrousi
- Laboratory of Physiology, School of Medicine University of Patras, Patras, Greece
| | - Maria-Eleni Lalioti
- Laboratory of Physiology, School of Medicine University of Patras, Patras, Greece
| | | | | | - Stavros Taraviras
- Laboratory of Physiology, School of Medicine University of Patras, Patras, Greece
| | - Zoi Lygerou
- Laboratory of Biology, School of Medicine, University of Patras, Patras, Greece
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22
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Ma XS, Lin F, Wang ZW, Hu MW, Huang L, Meng TG, Jiang ZZ, Schatten H, Wang ZB, Sun QY. Geminin deletion in mouse oocytes results in impaired embryo development and reduced fertility. Mol Biol Cell 2016; 27:768-75. [PMID: 26764091 PMCID: PMC4803303 DOI: 10.1091/mbc.e15-06-0346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 01/06/2016] [Indexed: 12/28/2022] Open
Abstract
Geminin is an important regulator of DNA replication and cell differentiation, but its role in female reproduction remains uncertain. Maternal geminin does not regulate oocyte meiotic maturation but does control accurate DNA replication. Geminin deletion in oocytes results in impaired embryo development and reduced fertility. Geminin controls proper centrosome duplication, cell division, and differentiation. We investigated the function of geminin in oogenesis, fertilization, and early embryo development by deleting the geminin gene in oocytes from the primordial follicle stage. Oocyte-specific disruption of geminin results in low fertility in mice. Even though there was no evident anomaly of oogenesis, oocyte meiotic maturation, natural ovulation, or fertilization, early embryo development and implantation were impaired. The fertilized eggs derived from mutant mice showed developmental delay, and many were blocked at the late zygote stage. Cdt1 protein was decreased, whereas Chk1 and H2AX phosphorylation was increased, in fertilized eggs after geminin depletion. Our results suggest that disruption of maternal geminin may decrease Cdt1 expression and cause DNA rereplication, which then activates the cell cycle checkpoint and DNA damage repair and thus impairs early embryo development.
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Affiliation(s)
- Xue-Shan Ma
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Fei Lin
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhong-Wei Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Meng-Wen Hu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China University of Chinese Academy of Sciences, Beijing 100101, China
| | - Lin Huang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tie-Gang Meng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China University of Chinese Academy of Sciences, Beijing 100101, China
| | - Zong-Zhe Jiang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211
| | - Zhen-Bo Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qing-Yuan Sun
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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23
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Stathopoulou A, Natarajan D, Nikolopoulou P, Patmanidi AL, Lygerou Z, Pachnis V, Taraviras S. Inactivation of Geminin in neural crest cells affects the generation and maintenance of enteric progenitor cells, leading to enteric aganglionosis. Dev Biol 2015; 409:392-405. [PMID: 26658318 DOI: 10.1016/j.ydbio.2015.11.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 11/27/2015] [Accepted: 11/27/2015] [Indexed: 11/25/2022]
Abstract
Neural crest cells comprise a multipotent, migratory cell population that generates a diverse array of cell and tissue types, during vertebrate development. Enteric Nervous System controls the function of the gastrointestinal tract and is mainly derived from the vagal and sacral neural crest cells. Deregulation on self-renewal and differentiation of the enteric neural crest cells is evident in enteric nervous system disorders, such as Hirschsprung disease, characterized by the absence of ganglia in a variable length of the distal bowel. Here we show that Geminin is essential for Enteric Nervous System generation as mice that lacked Geminin expression specifically in neural crest cells revealed decreased generation of vagal neural crest cells, and enteric neural crest cells (ENCCs). Geminin-deficient ENCCs showed increased apoptosis and decreased cell proliferation during the early stages of gut colonization. Furthermore, decreased number of committed ENCCs in vivo and the decreased self-renewal capacity of enteric progenitor cells in vitro, resulted in almost total aganglionosis resembling a severe case of Hirschsprung disease. Our results suggest that Geminin is an important regulator of self-renewal and survival of enteric nervous system progenitor cells.
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Affiliation(s)
| | - Dipa Natarajan
- Division of Molecular Neurobiology, MRC/National Institute for Medical Research, London, United Kingdom
| | | | | | - Zoi Lygerou
- Department of Biology, Medical School, University of Patras, Patras, Greece
| | - Vassilis Pachnis
- Division of Molecular Neurobiology, MRC/National Institute for Medical Research, London, United Kingdom
| | - Stavros Taraviras
- Department of Physiology, Medical School, University of Patras, Patras, Greece.
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High proliferation index, as determined by immunohistochemical expression of Aurora kinase B and geminin, indicates poor prognosis in neuroblastomas. Virchows Arch 2015. [PMID: 26199132 DOI: 10.1007/s00428-015-1806-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Expression profile analysis of cell cycle biomarkers provides a powerful index of the proliferative state of tumors, which is linked to disease aggressiveness. We investigated the impact of the biomarkers of S-G2-M phases of cell cycle, Aurora kinase B (AURKB) and geminin (GMNN), on disease progression in neuroblastomas. The expression of AURKB and GMNN was studied by immunostaining 84 neuroblastomas. A proliferation index (PI) was obtained on scanned immunostained slides using image analysis software. The median PI was 8.5 % for AURKB- and 16.8 % for GMNN-stained slides with a high correlation between the two (r s = 0.72, P < 0.001). The PI for both markers was significantly higher in neuroblastomas from patients with unfavorable clinical (high-risk group, advanced stage, age ≥18 months at presentation, primary abdominal compared to extra-abdominal sites), biological (MYCN amplification, 1p deletion, 17q gain), and pathological (undifferentiated or poorly differentiated status, high mitosis-karyorrhexis index, [MKI], unfavorable histology) factors. Using Cox regression models, a higher-than-median AURKB and GMNN PI was associated with a significantly shorter overall survival (OS) and event-free survival (EFS) in univariable analysis. In multivariable analysis, a high AURKB PI was associated with significantly shorter OS and EFS, independent of MYCN amplification, and significantly shorter EFS, independent of MKI. High GMNN PI was also associated with significantly shorter OS and EFS after adjusting for MYCN amplification but failed to reach statistical significance after adjusting for MKI. Our study shows that in neuroblastomas, AURKB- or GMNN-based PI provides valuable prognostic information and high PI indicates aggressive disease.
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Huang YY, Kaneko KJ, Pan H, DePamphilis ML. Geminin is Essential to Prevent DNA Re-Replication-Dependent Apoptosis in Pluripotent Cells, but not in Differentiated Cells. Stem Cells 2015; 33:3239-53. [PMID: 26140583 DOI: 10.1002/stem.2092] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 06/11/2015] [Indexed: 01/17/2023]
Abstract
Geminin is a dual-function protein unique to multicellular animals with roles in modulating gene expression and preventing DNA re-replication. Here, we show that geminin is essential at the beginning of mammalian development to prevent DNA re-replication in pluripotent cells, exemplified by embryonic stem cells, as they undergo self-renewal and differentiation. Embryonic stem cells, embryonic fibroblasts, and immortalized fibroblasts were characterized before and after geminin was depleted either by gene ablation or siRNA. Depletion of geminin under conditions that promote either self-renewal or differentiation rapidly induced DNA re-replication, followed by DNA damage, then a DNA damage response, and finally apoptosis. Once differentiation had occurred, geminin was no longer essential for viability, although it continued to contribute to preventing DNA re-replication induced DNA damage. No relationship was detected between expression of geminin and genes associated with either pluripotency or differentiation. Thus, the primary role of geminin at the beginning of mammalian development is to prevent DNA re-replication-dependent apoptosis, a role previously believed essential only in cancer cells. These results suggest that regulation of gene expression by geminin occurs only after pluripotent cells differentiate into cells in which geminin is not essential for viability.
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Affiliation(s)
- Yi-Yuan Huang
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Kotaro J Kaneko
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Haiyan Pan
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Melvin L DePamphilis
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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26
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Klein SL, Moody SA. Early neural ectodermal genes are activated by siamois and twin during blastula stages. Genesis 2015; 53:308-20. [PMID: 25892704 DOI: 10.1002/dvg.22854] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/13/2015] [Accepted: 04/14/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Steven L. Klein
- Department of Anatomy and Regenerative Biology; George Washington University, School of Medicine and Health Sciences; 2300 I Street Northwest Washington DC
| | - Sally A. Moody
- Department of Anatomy and Regenerative Biology; George Washington University, School of Medicine and Health Sciences; 2300 I Street Northwest Washington DC
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27
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Karamitros D, Patmanidi AL, Kotantaki P, Potocnik AJ, Bähr-Ivacevic T, Benes V, Lygerou Z, Kioussis D, Taraviras S. Geminin deletion increases the number of fetal hematopoietic stem cells by affecting the expression of key transcription factors. Development 2015; 142:70-81. [PMID: 25516969 DOI: 10.1242/dev.109454] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Balancing stem cell self-renewal and initiation of lineage specification programs is essential for the development and homeostasis of the hematopoietic system. We have specifically ablated geminin in the developing murine hematopoietic system and observed profound defects in the generation of mature blood cells, leading to embryonic lethality. Hematopoietic stem cells (HSCs) accumulated in the fetal liver following geminin ablation, while committed progenitors were reduced. Genome-wide transcriptome analysis identified key HSC transcription factors as being upregulated upon geminin deletion, revealing a gene network linked with geminin that controls fetal hematopoiesis. In order to obtain mechanistic insight into the ability of geminin to regulate transcription, we examined Hoxa9 as an example of a key gene in definitive hematopoiesis. We demonstrate that in human K562 cells geminin is associated with HOXA9 regulatory elements and its absence increases HOXA9 transcription similarly to that observed in vivo. Moreover, silencing geminin reduced recruitment of the PRC2 component SUZ12 to the HOXA9 locus and resulted in an increase in RNA polymerase II recruitment and H3K4 trimethylation (H3K4me3), whereas the repressive marks H3K9me3 and H3K27me3 were reduced. The chromatin landscape was also modified at the regulatory regions of HOXA10 and GATA1. K562 cells showed a reduced ability to differentiate to erythrocytes and megakaryocytes upon geminin silencing. Our data suggest that geminin is indispensable for fetal hematopoiesis and regulates the generation of a physiological pool of stem and progenitor cells in the fetal hematopoietic system.
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Affiliation(s)
- Dimitris Karamitros
- Department of Physiology, Medical School, University of Patras, Rio, Patras 26504, Greece
| | - Alexandra L Patmanidi
- Department of Physiology, Medical School, University of Patras, Rio, Patras 26504, Greece
| | - Panoraia Kotantaki
- Department of Physiology, Medical School, University of Patras, Rio, Patras 26504, Greece
| | - Alexandre J Potocnik
- Division of Molecular Immunology, MRC/National Institute for Medical Research, The Ridgeway, London NW7 1AA, UK
| | - Tomi Bähr-Ivacevic
- European Molecular Biology Laboratory (EMBL), Core Facilities and Services, Meyerhofstraße 1, Heidelberg 69117, Germany
| | - Vladimir Benes
- European Molecular Biology Laboratory (EMBL), Core Facilities and Services, Meyerhofstraße 1, Heidelberg 69117, Germany
| | - Zoi Lygerou
- Department of Biology, Medical School, University of Patras, Rio, Patras 26504, Greece
| | - Dimitris Kioussis
- Division of Molecular Immunology, MRC/National Institute for Medical Research, The Ridgeway, London NW7 1AA, UK
| | - Stavros Taraviras
- Department of Physiology, Medical School, University of Patras, Rio, Patras 26504, Greece
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28
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Edlund RK, Birol O, Groves AK. The role of foxi family transcription factors in the development of the ear and jaw. Curr Top Dev Biol 2015; 111:461-95. [PMID: 25662269 DOI: 10.1016/bs.ctdb.2014.11.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mammalian outer, middle, and inner ears have different embryonic origins and evolved at different times in the vertebrate lineage. The outer ear is derived from first and second branchial arch ectoderm and mesoderm, the middle ear ossicles are derived from neural crest mesenchymal cells that invade the first and second branchial arches, whereas the inner ear and its associated vestibule-acoustic (VIIIth) ganglion are derived from the otic placode. In this chapter, we discuss recent findings in the development of these structures and describe the contributions of members of a Forkhead transcription factor family, the Foxi family to their formation. Foxi transcription factors are critical for formation of the otic placode, survival of the branchial arch neural crest, and developmental remodeling of the branchial arch ectoderm.
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Affiliation(s)
- Renée K Edlund
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Onur Birol
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA; Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA.
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29
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Lee HK, Lee HS, Moody SA. Neural transcription factors: from embryos to neural stem cells. Mol Cells 2014; 37:705-12. [PMID: 25234468 PMCID: PMC4213760 DOI: 10.14348/molcells.2014.0227] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 08/10/2014] [Indexed: 01/01/2023] Open
Abstract
The early steps of neural development in the vertebrate embryo are regulated by sets of transcription factors that control the induction of proliferative, pluripotent neural precursors, the expansion of neural plate stem cells, and their transition to differentiating neural progenitors. These early events are critical for producing a pool of multipotent cells capable of giving rise to the multitude of neurons and glia that form the central nervous system. In this review we summarize findings from gain- and loss-of-function studies in embryos that detail the gene regulatory network responsible for these early events. We discuss whether this information is likely to be similar in mammalian embryonic and induced pluripotent stem cells that are cultured according to protocols designed to produce neurons. The similarities and differences between the embryo and stem cells may provide important guidance to stem cell protocols designed to create immature neural cells for therapeutic uses.
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Affiliation(s)
- Hyun-Kyung Lee
- ABRC, School of Life Sciences, BK21 Plus KNU Creative BioReserach Group, Kyungpook National University, Daegu 702-702,
Korea
| | - Hyun-Shik Lee
- ABRC, School of Life Sciences, BK21 Plus KNU Creative BioReserach Group, Kyungpook National University, Daegu 702-702,
Korea
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30
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Sharaby Y, Lahmi R, Amar O, Elbaz I, Lerer-Goldshtein T, Weiss AM, Appelbaum L, Tzur A. Gas2l3 is essential for brain morphogenesis and development. Dev Biol 2014; 394:305-13. [PMID: 25131197 DOI: 10.1016/j.ydbio.2014.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/30/2014] [Accepted: 08/04/2014] [Indexed: 11/19/2022]
Abstract
Growth arrest-specific 2-like 3 (Gas2l3) is a newly discovered cell cycle protein and a cytoskeleton orchestrator that binds both actin filament and microtubule networks. Studies of cultured mammalian cells established Gas2l3 as a regulator of the cell division process, in particular cytokinesis and cell abscission. Thus far, the role of Gas2l3 in vivo remains entirely unknown. In order to investigate Gas2l3 in developing vertebrates, we cloned the zebrafish gene. Spatiotemporal analysis of gas2l3 expression revealed a ubiquitous maternal transcript as well as a zygotic transcript primarily restricted to brain tissues. We next conducted a series of loss-of-function experiments, and searched for developmental anomalies at the end of the segmentation period. Our analysis revealed abnormal brain morphogenesis and ventricle formation in gas2l3 knockdown embryos. This signature phenotype could be rescued by elevated levels of gas2l3 RNA. At the tissue level, gas2l3 downregulation interferes with cell proliferation, suggesting that the cell cycle activities of Gas2l3 are essential for brain tissue homeostasis. Altogether, this study provides the first insight into the function of gas2l3 in vivo, demonstrating its essential role in brain development.
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Affiliation(s)
- Yaara Sharaby
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Roxane Lahmi
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Omer Amar
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Idan Elbaz
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Tali Lerer-Goldshtein
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Aryeh M Weiss
- Faculty of Engineering, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Lior Appelbaum
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Amit Tzur
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel; Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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31
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Schlosser G. Early embryonic specification of vertebrate cranial placodes. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2014; 3:349-63. [PMID: 25124756 DOI: 10.1002/wdev.142] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/09/2014] [Accepted: 05/16/2014] [Indexed: 12/16/2022]
Abstract
UNLABELLED Cranial placodes contribute to many sensory organs and ganglia of the vertebrate head. The olfactory, otic, and lateral line placodes form the sensory receptor cells and neurons of the nose, ear, and lateral line system; the lens placode develops into the lens of the eye; epibranchial, profundal, and trigeminal placodes contribute sensory neurons to cranial nerve ganglia; and the adenohypophyseal placode gives rise to the anterior pituitary, a major endocrine control organ. Despite these differences in fate, all placodes are now known to originate from a common precursor, the preplacodal ectoderm (PPE). The latter is a horseshoe-shaped domain of ectoderm surrounding the anterior neural plate and neural crest and is defined by expression of transcription factor Six1, its cofactor Eya1, and other members of the Six and Eya families. Studies in zebrafish, Xenopus, and chick reveal that the PPE is specified together with other ectodermal territories (epidermis, neural crest, and neural plate) during early embryogenesis. During gastrulation, domains of ventrally (e.g., Dlx3/Dlx5, GATA2/GATA3, AP2, Msx1, FoxI1, and Vent1/Vent2) and dorsally (e.g., Zic1, Sox3, and Geminin) restricted transcription factors are established in response to a gradient of BMP and help to define non-neural and neural competence territories, respectively. At neural plate stages, the PPE is then induced in the non-neural competence territory by signals from the adjacent neural plate and mesoderm including FGF, BMP inhibitors, and Wnt inhibitors. Subsequently, signals from more localized signaling centers induce restricted expression domains of various transcription factors within the PPE, which specify multiplacodal areas and ultimately individual placodes. For further resources related to this article, please visit the WIREs website. CONFLICT OF INTEREST The author has declared no conflicts of interest for this article.
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Affiliation(s)
- Gerhard Schlosser
- Department of Zoology, School of Natural Sciences & Regenerative Medicine Institute (REMEDI), National University of Ireland, Galway, Galway, Ireland
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Patterson ES, Waller LE, Kroll KL. Geminin loss causes neural tube defects through disrupted progenitor specification and neuronal differentiation. Dev Biol 2014; 393:44-56. [PMID: 24995796 DOI: 10.1016/j.ydbio.2014.06.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 01/13/2023]
Abstract
Geminin is a nucleoprotein that can directly bind chromatin regulatory complexes to modulate gene expression during development. Geminin knockout mouse embryos are preimplantation lethal by the 32-cell stage, precluding in vivo study of Geminin's role in neural development. Therefore, here we used a conditional Geminin allele in combination with several Cre-driver lines to define an essential role for Geminin during mammalian neural tube (NT) formation and patterning. Geminin was required in the NT within a critical developmental time window (embryonic day 8.5-10.5), when NT patterning and closure occurs. Geminin excision at these stages resulted in strongly diminished expression of genes that mark and promote dorsal NT identities and decreased differentiation of ventral motor neurons, resulting in completely penetrant NT defects, while excision after embryonic day 10.5 did not result in NT defects. When Geminin was deleted specifically in the spinal NT, both NT defects and axial skeleton defects were observed, but neither defect occurred when Geminin was excised in paraxial mesenchyme, indicating a tissue autonomous requirement for Geminin in developing neuroectoderm. Despite a potential role for Geminin in cell cycle control, we found no evidence of proliferation defects or altered apoptosis. Comparisons of gene expression in the NT of Geminin mutant versus wild-type siblings at embryonic day 10.5 revealed decreased expression of key regulators of neurogenesis, including neurogenic bHLH transcription factors and dorsal interneuron progenitor markers. Together, these data demonstrate a requirement for Geminin for NT patterning and neuronal differentiation during mammalian neurulation in vivo.
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Affiliation(s)
- Ethan S Patterson
- Department of Developmental Biology, Washington University School of Medicine, 320 McDonnell Sciences Building, Campus Box 8103, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Laura E Waller
- Department of Developmental Biology, Washington University School of Medicine, 320 McDonnell Sciences Building, Campus Box 8103, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Kristen L Kroll
- Department of Developmental Biology, Washington University School of Medicine, 320 McDonnell Sciences Building, Campus Box 8103, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
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Caronna EA, Patterson ES, Hummert PM, Kroll KL. Geminin restrains mesendodermal fate acquisition of embryonic stem cells and is associated with antagonism of Wnt signaling and enhanced polycomb-mediated repression. Stem Cells 2014; 31:1477-87. [PMID: 23630199 DOI: 10.1002/stem.1410] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 04/04/2013] [Indexed: 11/07/2022]
Abstract
Embryonic cells use both growth factor signaling and cell intrinsic transcriptional and epigenetic regulation to acquire early cell fates. Underlying mechanisms that integrate these cues are poorly understood. Here, we investigated the role of Geminin, a nucleoprotein that interacts with both transcription factors and epigenetic regulatory complexes, during fate acquisition of mouse embryonic stem cells. In order to determine Geminin's role in mesendoderm formation, a process which occurs during embryonic gastrulation, we selectively over-expressed or knocked down Geminin in an in vitro model of differentiating mouse embryonic stem cells. We found that Geminin antagonizes mesendodermal fate acquisition, while these cells instead maintain elevated expression of genes associated with pluripotency of embryonic stem cells. During mesendodermal fate acquisition, Geminin knockdown promotes Wnt signaling, while Bmp, Fgf, and Nodal signaling are not affected. Moreover, we showed that Geminin facilitates the repression of mesendodermal genes that are regulated by the Polycomb repressor complex. Geminin directly binds several of these genes, while Geminin knockdown in mesendodermal cells reduces Polycomb repressor complex occupancy at these loci and increases trimethylation of histone H3 lysine 4, which correlates with active gene expression. Together, these results indicate that Geminin is required to restrain mesendodermal fate acquisition of early embryonic cells and that this is associated with both decreased Wnt signaling and enhanced Polycomb repressor complex retention at mesendodermal genes.
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Affiliation(s)
- Elizabeth A Caronna
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
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Hardwick LJA, Ali FR, Azzarelli R, Philpott A. Cell cycle regulation of proliferation versus differentiation in the central nervous system. Cell Tissue Res 2014; 359:187-200. [PMID: 24859217 PMCID: PMC4284380 DOI: 10.1007/s00441-014-1895-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 04/10/2014] [Indexed: 01/07/2023]
Abstract
Formation of the central nervous system requires a period of extensive progenitor cell proliferation, accompanied or closely followed by differentiation; the balance between these two processes in various regions of the central nervous system gives rise to differential growth and cellular diversity. The correlation between cell cycle lengthening and differentiation has been reported across several types of cell lineage and from diverse model organisms, both in vivo and in vitro. Furthermore, different cell fates might be determined during different phases of the preceding cell cycle, indicating direct cell cycle influences on both early lineage commitment and terminal cell fate decisions. Significant advances have been made in the last decade and have revealed multi-directional interactions between the molecular machinery regulating the processes of cell proliferation and neuronal differentiation. Here, we first introduce the modes of proliferation in neural progenitor cells and summarise evidence linking cell cycle length and neuronal differentiation. Second, we describe the manner in which components of the cell cycle machinery can have additional and, sometimes, cell-cycle-independent roles in directly regulating neurogenesis. Finally, we discuss the way that differentiation factors, such as proneural bHLH proteins, can promote either progenitor maintenance or differentiation according to the cellular environment. These intricate connections contribute to precise coordination and the ultimate division versus differentiation decision.
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Affiliation(s)
- Laura J A Hardwick
- Department of Oncology, Hutchison/MRC Research Centre, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XZ, UK
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Hardwick LJA, Philpott A. Nervous decision-making: to divide or differentiate. Trends Genet 2014; 30:254-61. [PMID: 24791612 PMCID: PMC4046230 DOI: 10.1016/j.tig.2014.04.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/31/2014] [Accepted: 04/01/2014] [Indexed: 01/07/2023]
Abstract
Multiple mechanisms coordinate the cell cycle and neuronal differentiation. Lengthening of G1 phase is functionally important for differentiation. Cell cycle components can directly and independently affect neurogenesis. Differentiation factors can directly affect the cell cycle structure and machinery.
The intricate balance between proliferation and differentiation is of fundamental importance in the development of the central nervous system (CNS). The division versus differentiation decision influences both the number and identity of daughter cells produced, thus critically shaping the overall microstructure and function of the CNS. During the past decade, significant advances have been made to characterise the changes in the cell cycle during differentiation, and to uncover the multiple bidirectional links that coordinate these two processes. Here, we explore the nature and mechanistic basis of these links in the context of the developing CNS, highlighting new insights into transcriptional, post-translational, and epigenetic levels of interaction.
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Affiliation(s)
- Laura J A Hardwick
- Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, Cambridge, CB2 0XZ, UK
| | - Anna Philpott
- Department of Oncology, University of Cambridge, Hutchison/MRC Research Centre, Cambridge Biomedical Campus, Cambridge, CB2 0XZ, UK.
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Blanchard Z, Mullins N, Ellipeddi P, Lage JM, McKinney S, El-Etriby R, Zhang X, Isokpehi R, Hernandez B, ElShamy WM. Geminin overexpression promotes imatinib sensitive breast cancer: a novel treatment approach for aggressive breast cancers, including a subset of triple negative. PLoS One 2014; 9:e95663. [PMID: 24789045 PMCID: PMC4005756 DOI: 10.1371/journal.pone.0095663] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 03/28/2014] [Indexed: 11/18/2022] Open
Abstract
Breast cancer is the second leading cause of cancer-related deaths in women. Triple negative breast cancer (TNBC) is an aggressive subtype that affects 10–25% mostly African American women. TNBC has the poorest prognosis of all subtypes with rapid progression leading to mortality in younger patients. So far, there is no targeted treatment for TNBC. To that end, here we show that c-Abl is one of several tyrosine kinases that phosphorylate and activate geminin’s ability to promote TNBC. Analysis of >800 breast tumor samples showed that geminin is overexpressed in ∼50% of all tumors. Although c-Abl is overexpressed in ∼90% of all tumors, it is only nuclear in geminin overexpressing tumors. In geminin-negative tumors, c-Abl is only cytoplasmic. Inhibiting c-Abl expression or activity (using imatinib or nilotinib) prevented geminin Y150 phosphorylation, inactivated the protein, and most importantly converted overexpressed geminin from an oncogene to an apoptosis inducer. In pre-clinical orthotopic breast tumor models, geminin-overexpressing cells developed aneuploid and invasive tumors, which were suppressed when c-Abl expression was blocked. Moreover, established geminin overexpressing orthotopic tumors regressed when treated with imatinib or nilotinib. Our studies support imatinib/nilotonib as a novel treatment option for patients with aggressive breast cancer (including a subset of TNBCs)-overexpressing geminin and nuclear c-Abl.
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Affiliation(s)
- Zannel Blanchard
- Cancer Institute, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Nicole Mullins
- Cancer Institute, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Pavani Ellipeddi
- Cancer Institute, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Janice M. Lage
- Department of Pathology, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Shawn McKinney
- Department of Surgery, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Rana El-Etriby
- Cancer Institute, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Xu Zhang
- Center of Biostatistics and Bioinformatics, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Raphael Isokpehi
- Center for Bioinformatics & Computational Biology, Department of Biology, Jackson State University, Jackson, Mississippi, United States of America
| | - Brenda Hernandez
- Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Wael M. ElShamy
- Cancer Institute, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi, United States of America
- * E-mail:
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Champeris Tsaniras S, Kanellakis N, Symeonidou IE, Nikolopoulou P, Lygerou Z, Taraviras S. Licensing of DNA replication, cancer, pluripotency and differentiation: an interlinked world? Semin Cell Dev Biol 2014; 30:174-80. [PMID: 24641889 DOI: 10.1016/j.semcdb.2014.03.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/10/2014] [Indexed: 01/06/2023]
Abstract
Recent findings provide evidence for a functional interplay between DNA replication and the seemingly distinct areas of cancer, development and pluripotency. Protein complexes participating in DNA replication origin licensing are now known to have roles in development, while their deregulation can lead to cancer. Moreover, transcription factors implicated in the maintenance of or reversal to the pluripotent state have links to the pre-replicative machinery. Several studies have shown that overexpression of these factors is associated to cancer.
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Affiliation(s)
- S Champeris Tsaniras
- Department of Physiology, Medical School, University of Patras, Rio, 26504 Patras, Greece.
| | - N Kanellakis
- Department of Physiology, Medical School, University of Patras, Rio, 26504 Patras, Greece.
| | - I E Symeonidou
- Department of Biology, Medical School, University of Patras, Rio, 26504 Patras, Greece.
| | - P Nikolopoulou
- Department of Physiology, Medical School, University of Patras, Rio, 26504 Patras, Greece.
| | - Z Lygerou
- Department of Biology, Medical School, University of Patras, Rio, 26504 Patras, Greece.
| | - S Taraviras
- Department of Physiology, Medical School, University of Patras, Rio, 26504 Patras, Greece.
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Ohno Y, Saeki K, Yasunaga S, Kurogi T, Suzuki-Takedachi K, Shirai M, Mihara K, Yoshida K, Voncken JW, Ohtsubo M, Takihara Y. Transcription of the Geminin gene is regulated by a negative-feedback loop. Mol Biol Cell 2014; 25:1374-83. [PMID: 24554762 PMCID: PMC3983001 DOI: 10.1091/mbc.e13-09-0534] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Geminin transcription, regulated by E2Fs, is negatively regulated by Geminin through the inhibition of chromatin remodeling. Geminin transcription is thus regulated by a negative-feedback loop through the chromatin configuration. Homeostatically regulated Geminin may help couple regulation of DNA replication and transcription. Geminin performs a central function in regulating cellular proliferation and differentiation in development and also in stem cells. Of interest, down-regulation of Geminin induces gene transcription regulated by E2F, indicating that Geminin is involved in regulation of E2F-mediated transcriptional activity. Because transcription of the Geminin gene is reportedly regulated via an E2F-responsive region (E2F-R) located in the first intron, we first used a reporter vector to examine the effect of Geminin on E2F-mediated transcriptional regulation. We found that Geminin transfection suppressed E2F1- and E2F2-mediated transcriptional activation and also mildly suppressed such activity in synergy with E2F5, 6, and 7, suggesting that Geminin constitutes a negative-feedback loop for the Geminin promoter. Of interest, Geminin also suppressed nuclease accessibility, acetylation of histone H3, and trimethylation of histone H3 at lysine 4, which were induced by E2F1 overexpression, and enhanced trimethylation of histone H3 at lysine 27 and monoubiquitination of histone H2A at lysine 119 in E2F-R. However, Geminin5EQ, which does not interact with Brahma or Brg1, did not suppress accessibility to nuclease digestion or transcription but had an overall dominant-negative effect. These findings suggest that E2F-mediated activation of Geminin transcription is negatively regulated by Geminin through the inhibition of chromatin remodeling.
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Affiliation(s)
- Yoshinori Ohno
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553, Japan Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center Research Institute, Suita 562-0025, Japan Department of Life Sciences, Meiji University School of Agriculture, Kawasaki 214-8571, Japan Department of Molecular Genetics, Maastricht University Medical Centre, 6229ER Maastricht, Netherlands Department of Food and Fermentation Science, Faculty of Food Science and Nutrition, Beppu University, Beppu 874-0915, Japan
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39
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The dual roles of geminin during trophoblast proliferation and differentiation. Dev Biol 2014; 387:49-63. [PMID: 24412371 DOI: 10.1016/j.ydbio.2013.12.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Revised: 12/11/2013] [Accepted: 12/22/2013] [Indexed: 11/21/2022]
Abstract
Geminin is a protein involved in both DNA replication and cell fate acquisition. Although it is essential for mammalian preimplantation development, its role remains unclear. In one study, ablation of the geminin gene (Gmnn) in mouse preimplantation embryos resulted in apoptosis, suggesting that geminin prevents DNA re-replication, whereas in another study it resulted in differentiation of blastomeres into trophoblast giant cells (TGCs), suggesting that geminin regulates trophoblast specification and differentiation. Other studies concluded that trophoblast differentiation into TGCs is regulated by fibroblast growth factor-4 (FGF4), and that geminin is required to maintain endocycles. Here we show that ablation of Gmnn in trophoblast stem cells (TSCs) proliferating in the presence of FGF4 closely mimics the events triggered by FGF4 deprivation: arrest of cell proliferation, formation of giant cells, excessive DNA replication in the absence of DNA damage and apoptosis, and changes in gene expression that include loss of Chk1 with up-regulation of p57 and p21. Moreover, FGF4 deprivation of TSCs reduces geminin to a basal level that is required for maintaining endocycles in TGCs. Thus, geminin acts both like a component of the FGF4 signal transduction pathway that governs trophoblast proliferation and differentiation, and geminin is required to maintain endocycles.
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40
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Setting appropriate boundaries: fate, patterning and competence at the neural plate border. Dev Biol 2013; 389:2-12. [PMID: 24321819 DOI: 10.1016/j.ydbio.2013.11.027] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 11/20/2022]
Abstract
The neural crest and craniofacial placodes are two distinct progenitor populations that arise at the border of the vertebrate neural plate. This border region develops through a series of inductive interactions that begins before gastrulation and progressively divide embryonic ectoderm into neural and non-neural regions, followed by the emergence of neural crest and placodal progenitors. In this review, we describe how a limited repertoire of inductive signals-principally FGFs, Wnts and BMPs-set up domains of transcription factors in the border region which establish these progenitor territories by both cross-inhibitory and cross-autoregulatory interactions. The gradual assembly of different cohorts of transcription factors that results from these interactions is one mechanism to provide the competence to respond to inductive signals in different ways, ultimately generating the neural crest and cranial placodes.
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41
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Caillat C, Pefani DE, Gillespie PJ, Taraviras S, Blow JJ, Lygerou Z, Perrakis A. The Geminin and Idas coiled coils preferentially form a heterodimer that inhibits Geminin function in DNA replication licensing. J Biol Chem 2013; 288:31624-34. [PMID: 24064211 PMCID: PMC3814758 DOI: 10.1074/jbc.m113.491928] [Citation(s) in RCA: 17] [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: 06/06/2013] [Revised: 08/28/2013] [Indexed: 01/03/2023] Open
Abstract
Geminin is an important regulator of proliferation and differentiation in metazoans, which predominantly inhibits the DNA replication licensing factor Cdt1, preventing genome over-replication. We show that Geminin preferentially forms stable coiled-coil heterodimers with its homologue, Idas. In contrast to Idas-Geminin heterodimers, Idas homodimers are thermodynamically unstable and are unlikely to exist as a stable macromolecule under physiological conditions. The crystal structure of the homology regions of Idas in complex with Geminin showed a tight head-to-head heterodimeric coiled-coil. This Idas-Geminin heterodimer binds Cdt1 less strongly than Geminin-Geminin, still with high affinity (∼30 nm), but with notably different thermodynamic properties. Consistently, in Xenopus egg extracts, Idas-Geminin is less active in licensing inhibition compared with a Geminin-Geminin homodimer. In human cultured cells, ectopic expression of Idas leads to limited over-replication, which is counteracted by Geminin co-expression. The properties of the Idas-Geminin complex suggest it as the functional form of Idas and provide a possible mechanism to modulate Geminin activity.
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Affiliation(s)
- Christophe Caillat
- From the Division of Biochemistry, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | | | - Peter J. Gillespie
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom, and
| | - Stavros Taraviras
- Laboratory of Physiology, School of Medicine, University of Patras, 26505 Rio, Patras, Greece
| | - J. Julian Blow
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom, and
| | - Zoi Lygerou
- Laboratory of Biology, School of Medicine, University of Patras, 26505 Rio, Patras, Greece
| | - Anastassis Perrakis
- From the Division of Biochemistry, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
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42
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Tabrizi GA, Böse K, Reimann Y, Kessel M. Geminin is required for the maintenance of pluripotency. PLoS One 2013; 8:e73826. [PMID: 24069236 PMCID: PMC3777968 DOI: 10.1371/journal.pone.0073826] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 07/23/2013] [Indexed: 12/28/2022] Open
Abstract
Pluripotency requires the expression of the three core transcriptions factors Oct4, Sox2 and Nanog, as well as further, complementary proteins. The geminin protein is part of this network, and was shown to play a role in the regulation of DNA replication, the control of the cell cycle, and the acquisition of neural fate. It is highly expressed in the early embryo, in particular the epiblast and the early neural ectoderm, and also in pluripotent embryonic stem cells. The genetic inactivation of geminin resulted in lethality after the first few cell divisions, and thus prohibited the outgrowth of pluripotent cells. We established embryonic stem cells allowing the deletion of the geminin gene by induction of of Cre-recombinase with tamoxifen. Here, we show that geminin deficiency quickly leads to a loss of pluripotency, and to differentiation into the mesendodermal direction with high Oct4/low Sox2 levels. Simultaneous loss of geminin and induction of the neural lineage resulted in immediate apoptosis. These results suggested that in early development geminin functions via the co-expressed Sox2 gene. We found that the stem cell enhancer SRR2 of Sox2 is occupied by the activating esBAF complex in the presence of geminin, but becomes epigenetically repressed in its absence by the Polycomb repressive complex PRC2. The importance of geminin for Sox2 expression also explains the absolute requirement for geminin during the induction of pluripotency by OSKM viruses. In summary, geminin is required for Sox2 expression, and thus for the maintenance of totipotency, pluripotency and the early neural lineage.
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Affiliation(s)
| | - Kerstin Böse
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Yvonne Reimann
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Michael Kessel
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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43
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Fukushima H, Ogura K, Wan L, Lu Y, Li V, Gao D, Liu P, Lau AW, Wu T, Kirschner MW, Inuzuka H, Wei W. SCF-mediated Cdh1 degradation defines a negative feedback system that coordinates cell-cycle progression. Cell Rep 2013; 4:803-16. [PMID: 23972993 PMCID: PMC3839583 DOI: 10.1016/j.celrep.2013.07.031] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 06/18/2013] [Accepted: 07/19/2013] [Indexed: 12/31/2022] Open
Abstract
Proper cell-cycle transitions are driven by waves of ubiquitin-dependent degradation of key regulators by the anaphase-promoting complex (APC) and Skp1-Cullin1-F-box (SCF) E3 ubiquitin ligase complexes. But precisely how APC and SCF activities are coordinated to regulate cell-cycle progression remains largely unclear. We previously showed that APC/Cdh1 earmarks the SCF component Skp2 for degradation. Here, we continue to report that SCF(β-TRCP) reciprocally controls APC/Cdh1 activity by governing Cdh1 ubiquitination and subsequent degradation. Furthermore, we define both cyclin A and Plk1, two well-known Cdh1 substrates, as upstream modifying enzymes that promote Cdh1 phosphorylation to trigger Cdh1 ubiquitination and subsequent degradation by SCF(β-TRCP). Thus, our work reveals a negative repression mechanism for SCF to control APC, thereby illustrating an elegant dual repression system between these two E3 ligase complexes to create the ordered cascade of APC and SCF activities governing timely cell-cycle transitions.
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Affiliation(s)
- Hidefumi Fukushima
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Kohei Ogura
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Lixin Wan
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Ying Lu
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Victor Li
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Daming Gao
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Pengda Liu
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Alan W. Lau
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Tao Wu
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Marc W. Kirschner
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Hiroyuki Inuzuka
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Wenyi Wei
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Shu J, Wu C, Wu Y, Li Z, Shao S, Zhao W, Tang X, Yang H, Shen L, Zuo X, Yang W, Shi Y, Chi X, Zhang H, Gao G, Shu Y, Yuan K, He W, Tang C, Zhao Y, Deng H. Induction of pluripotency in mouse somatic cells with lineage specifiers. Cell 2013; 153:963-75. [PMID: 23706735 DOI: 10.1016/j.cell.2013.05.001] [Citation(s) in RCA: 214] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 02/13/2013] [Accepted: 04/15/2013] [Indexed: 11/15/2022]
Abstract
The reprogramming factors that induce pluripotency have been identified primarily from embryonic stem cell (ESC)-enriched, pluripotency-associated factors. Here, we report that, during mouse somatic cell reprogramming, pluripotency can be induced with lineage specifiers that are pluripotency rivals to suppress ESC identity, most of which are not enriched in ESCs. We found that OCT4 and SOX2, the core regulators of pluripotency, can be replaced by lineage specifiers that are involved in mesendodermal (ME) specification and in ectodermal (ECT) specification, respectively. OCT4 and its substitutes attenuated the elevated expression of a group of ECT genes, whereas SOX2 and its substitutes curtailed a group of ME genes during reprogramming. Surprisingly, the two counteracting lineage specifiers can synergistically induce pluripotency in the absence of both OCT4 and SOX2. Our study suggests a "seesaw model" in which a balance that is established using pluripotency factors and/or counteracting lineage specifiers can facilitate reprogramming.
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Affiliation(s)
- Jian Shu
- MOE Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China
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45
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Janesick A, Abbey R, Chung C, Liu S, Taketani M, Blumberg B. ERF and ETV3L are retinoic acid-inducible repressors required for primary neurogenesis. Development 2013; 140:3095-106. [PMID: 23824578 DOI: 10.1242/dev.093716] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cells in the developing neural tissue demonstrate an exquisite balance between proliferation and differentiation. Retinoic acid (RA) is required for neuronal differentiation by promoting expression of proneural and neurogenic genes. We show that RA acts early in the neurogenic pathway by inhibiting expression of neural progenitor markers Geminin and Foxd4l1, thereby promoting differentiation. Our screen for RA target genes in early Xenopus development identified Ets2 Repressor Factor (Erf) and the closely related ETS repressors Etv3 and Etv3-like (Etv3l). Erf and Etv3l are RA responsive and inhibit the action of ETS genes downstream of FGF signaling, placing them at the intersection of RA and growth factor signaling. We hypothesized that RA regulates primary neurogenesis by inducing Erf and Etv3l to antagonize proliferative signals. Loss-of-function analysis showed that Erf and Etv3l are required to inhibit proliferation of neural progenitors to allow differentiation, whereas overexpression of Erf led to an increase in the number of primary neurons. Therefore, these RA-induced ETS repressors are key components of the proliferation-differentiation switch during primary neurogenesis in vivo.
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Affiliation(s)
- Amanda Janesick
- Department of Developmental and Cell Biology, 2011 Biological Sciences 3, University of California, Irvine, CA 92697-2300, USA
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46
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Slawny N, O'Shea KS. Geminin promotes an epithelial-to-mesenchymal transition in an embryonic stem cell model of gastrulation. Stem Cells Dev 2013; 22:1177-89. [PMID: 23249188 DOI: 10.1089/scd.2012.0050] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Geminin is a nuclear protein that performs the related functions of modulating cell cycle progression by binding Cdt1, and controlling differentiation by binding transcription factors. Since embryonic stem cells (ESC) and the epiblast share a similar gene expression profile and an attenuated cell cycle, ESC form an accessible and tractable model system to study lineage choice at gastrulation. We derived several ESC lines in which Geminin can be inducibly expressed, and employed short hairpin RNAs targeting Geminin. As in the embryo, a lack of Geminin protein resulted in DNA damage and cell death. In monolayer culture, in defined medium, Geminin supported neural differentiation; however, in three-dimensional culture, overexpression of Geminin promoted mesendodermal differentiation and epithelial-to-mesenchymal transition. In vitro, ESC overexpressing Geminin rapidly recolonized a wound, downregulated E-cadherin expression, and activated Wnt signaling. We suggest that Geminin may promote differentiation via binding Groucho/TLE proteins and upregulating canonical Wnt signaling.
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Affiliation(s)
- Nicole Slawny
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-2200, USA
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47
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ZEB1 imposes a temporary stage-dependent inhibition of muscle gene expression and differentiation via CtBP-mediated transcriptional repression. Mol Cell Biol 2013; 33:1368-82. [PMID: 23339872 DOI: 10.1128/mcb.01259-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Skeletal muscle development is orchestrated by the myogenic regulatory factor MyoD, whose activity is blocked in myoblasts by proteins preventing its nuclear translocation and/or binding to G/C-centered E-boxes in target genes. Recent evidence indicates that muscle gene expression is also regulated at the cis level by differential affinity for DNA between MyoD and other E-box binding proteins during myogenesis. MyoD binds to G/C-centered E-boxes, enriched in muscle differentiation genes, in myotubes but not in myoblasts. Here, we used cell-based and in vivo Drosophila, Xenopus laevis, and mouse models to show that ZEB1, a G/C-centered E-box binding transcriptional repressor, imposes a temporary stage-dependent inhibition of muscle gene expression and differentiation via CtBP-mediated transcriptional repression. We found that, contrary to MyoD, ZEB1 binds to G/C-centered E-boxes in muscle differentiation genes at the myoblast stage but not in myotubes. Its knockdown results in precocious expression of muscle differentiation genes and acceleration of myotube formation. Inhibition of muscle genes by ZEB1 occurs via transcriptional repression and involves recruitment of the CtBP corepressor. Lastly, we show that the pattern of gene expression associated with muscle differentiation is accelerated in ZEB1(-/-) mouse embryos. These results set ZEB1 as an important regulator of the temporal pattern of gene expression controlling muscle differentiation.
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48
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Ohno Y, Yasunaga S, Janmohamed S, Ohtsubo M, Saeki K, Kurogi T, Mihara K, Iscove NN, Takihara Y. Hoxa9 transduction induces hematopoietic stem and progenitor cell activity through direct down-regulation of geminin protein. PLoS One 2013; 8:e53161. [PMID: 23326393 PMCID: PMC3543444 DOI: 10.1371/journal.pone.0053161] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 11/26/2012] [Indexed: 12/11/2022] Open
Abstract
Hoxb4, a 3′-located Hox gene, enhances hematopoietic stem cell (HSC) activity, while a subset of 5′-located Hox genes is involved in hematopoiesis and leukemogenesis, and some of them are common translocation partners for Nucleoporin 98 (Nup98) in patients with leukemia. Although these Hox gene derivatives are believed to act as transcription regulators, the molecular involvement of the Hox gene derivatives in hematopoiesis and leukemogenesis remains largely elusive. Since we previously showed that Hoxb4 forms a complex with a Roc1-Ddb1-Cul4a ubiquitin ligase core component and functions as an E3 ubiquitin ligase activator for Geminin, we here examined the E3 ubiquitin ligase activities of the 5′-located Hox genes, Hoxa9 and Hoxc13, and Nup98-Hoxa9. Hoxa9 formed a similar complex with the Roc1-Ddb1-Cul4a component to induce ubiquitination of Geminin, but the others did not. Retroviral transduction-mediated overexpression or siRNA-mediated knock-down of Hoxa9 respectively down-regulated or up-regulated Geminin in hematopoietic cells. And Hoxa9 transduction-induced repopulating and clonogenic activities were suppressed by Geminin supertransduction. These findings suggest that Hoxa9 and Hoxb4 differ from Hoxc13 and Nup98-Hoxa9 in their molecular role in hematopoiesis, and that Hoxa9 induces the activity of HSCs and hematopoietic progenitors at least in part through direct down-regulation of Geminin.
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Affiliation(s)
- Yoshinori Ohno
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Shin'ichiro Yasunaga
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Salima Janmohamed
- Ontario Cancer Institute, McEwen Centre for Regenerative Medicine, Departments of Medical Biophysics and Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Motoaki Ohtsubo
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
- Department of Food and Fermentation Science, Faculty of Food Science and Nutrition, Beppu University, Beppu, Oita, Japan
| | - Keita Saeki
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Toshiaki Kurogi
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Keichiro Mihara
- Department of Hematology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Norman N. Iscove
- Ontario Cancer Institute, McEwen Centre for Regenerative Medicine, Departments of Medical Biophysics and Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Yoshihiro Takihara
- Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
- * E-mail:
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49
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Geminin regulates the transcriptional and epigenetic status of neuronal fate-promoting genes during mammalian neurogenesis. Mol Cell Biol 2012; 32:4549-60. [PMID: 22949506 DOI: 10.1128/mcb.00737-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Regulating the transition from lineage-restricted progenitors to terminally differentiated cells is a central aspect of nervous system development. Here, we investigated the role of the nucleoprotein geminin in regulating neurogenesis at a mechanistic level during both Xenopus primary neurogenesis and mammalian neuronal differentiation in vitro. The latter work utilized neural cells derived from embryonic stem and embryonal carcinoma cells in vitro and neural stem cells from mouse forebrain. In all of these contexts, geminin antagonized the ability of neural basic helix-loop-helix (bHLH) transcription factors to activate transcriptional programs promoting neurogenesis. Furthermore, geminin promoted a bivalent chromatin state, characterized by the presence of both activating and repressive histone modifications, at genes encoding transcription factors that promote neurogenesis. This epigenetic state restrains the expression of genes that regulate commitment of undifferentiated stem and neuronal precursor cells to neuronal lineages. However, maintaining geminin at high levels was not sufficient to prevent terminal neuronal differentiation. Therefore, these data support a model whereby geminin promotes the neuronal precursor cell state by modulating both the epigenetic status and expression of genes encoding neurogenesis-promoting factors. Additional developmental signals acting in these cells can then control their transition toward terminal neuronal or glial differentiation during mammalian neurogenesis.
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50
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Barry KA, Schultz KM, Payne CJ, McGarry TJ. Geminin is required for mitotic proliferation of spermatogonia. Dev Biol 2012; 371:35-46. [PMID: 22898305 DOI: 10.1016/j.ydbio.2012.07.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 07/24/2012] [Accepted: 07/31/2012] [Indexed: 12/22/2022]
Abstract
Spermatogonial stem cells divide throughout life, maintaining their own population and giving rise to differentiated gametes. The unstable regulatory protein Geminin is thought to be one of the factors that determine whether stem cells continue to divide or terminally differentiate. Geminin regulates the extent of DNA replication and is thought to maintain cells in an undifferentiated state by inhibiting various transcription factors and chromatin remodeling proteins. To examine how Geminin might regulate spermatogenesis, we developed two conditional mouse models in which the Geminin gene (Gmnn) is deleted from either spermatogonia or meiotic spermatocytes. Deleting Geminin from spermatogonia causes complete sterility in male mice. Gmnn(-/-) spermatogonia disappear during the initial wave of mitotic proliferation that occurs during the first week of life. Gmnn(-/-) spermatogonia exhibit more double-stranded DNA breaks than control cells, consistent with a defect in DNA replication. They maintain expression of genes associated with the undifferentiated state and do not prematurely express genes characteristic of more differentiated spermatogonia. In contrast, deleting Geminin from spermatocytes does not disrupt meiosis or the differentiation of spermatids into mature sperm. In females, Geminin is not required for meiosis, oocyte differentiation, or fertility after the embryonic period of mitotic proliferation has ceased. We conclude that Geminin is absolutely required for mitotic proliferation of spermatogonia but does not regulate their differentiation. Our results suggest that Geminin maintains replication fidelity during the mitotic phase of spermatogenesis, ensuring the precise duplication of genetic information for transmission to the next generation.
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Affiliation(s)
- Kelly A Barry
- Feinberg Cardiovascular Research Institute, Department of Medicine, and Department of Cell and Molecular Biology, Northwestern University, Chicago, IL 60611, USA
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